Coach Jeff

Written by Coach Jeff


Losing Running Fitness: A Scientific Look at How Much You’ll Slow Down When Not Able to Run

How much will taking a few days off from running hurt my fitness?

It’s one of the most common questions I get from runners struggling with an injury, fighting the flu, or hesitant to take a much needed rest from training. As runners, we are all paranoid about taking a few days off, generally thinking it will ruin our months of meticulous training.

As a coach, I am not immune to being frightened by this irrational fear.

While I was training for the NCAA championships while in college, I had a swimming accident that left my left shoulder separated and required a visit to the hospital to get it back in place. The doctors told me I needed to take a few days off to let the shoulder heal.

Not wanting lose any precious training time, I strapped my left arm tight across my body using a combination of saran wrap and duct tape and went on a 12-mile run the next morning. Luckily, I didn’t suffer any lingering affects from the imbalances I created by running with one arm.

However, I wanted to share this story with you to demonstrate that I write this article with the deepest understanding of how hard it can be to listen to science and understand that a day off isn’t going to end your hopes of running as fast as you’ve dreamed.

When we look at the effects of taking time off from running, we have to analyze the detraining from two perspectives: (1) your metabolic systems such as aerobic fitness, threshold and VO2 max; and (2) your structural systems such as your muscles and neuromuscular coordination (how fast and efficiently your brain can tell your body to perform and execute a specific movement).

Learn exactly how much fitness and conditioning you'll lose from missing running due to injury or sickness.

Effect of detraining on the aerobic system

Because VO2 max is one of the best measurements of a runners physical fitness, I will use it as the baseline to compare the effects of detraining on your aerobic system. To be brief, VO2 max is an individual’s maximum ability to transport and use oxygen during exercise (here’s more information if you need).

Recent studies show that there is little reduction in VO2max for the first 10 days following inactivity in well-trained athletes. It is prudent here to mention that all of these guidelines assume you are a decently trained runner, having trained consistently for a 4-6 month period. Beginner runners will lose fitness at a slightly faster rate since they have a smaller base of fitness.

After two weeks of not running, studies show that VO2 max decreases by 6%. After 9 weeks VO2 max drops by 19% (sorry, I couldn’t find any data on 3-8 weeks post inactivity). After 11 weeks of no running, Studies demonstrate that VO2 max falls by 25.7% from peak physical fitness.

So, as you can see, from an aerobic standpoint, you have very little to worry about if you have to take a break from running for two weeks or less.

This is very important for those runners that need to take a hiatus because of a small injury or are nervous about taking downtime after a long training segment. A 6% decline in VO2 max can be made up with one or two weeks of solid training.

While percentages are fantastic, what do those numbers really mean for runners?

Let’s use an example of a 20 minute 5k runner. A 20 minute 5k runner has a VO2max of roughly 49.81 ml/kg/min (estimated using a formula). After 2 weeks of no running, the 5k runner would lose 6% of his VO2 max, which would be 46.83 and would now be in 21:05 shape, according to most estimates.

After 9 weeks of no running, the same 20-minute 5k runner would now be in 24:00 minute 5k shape. After 11 weeks of no running, our poor running friend would be in 25:30 shape.

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Effect of detraining on the structural system

While the reduction in aerobic fitness has been tolerably studied in an applicable manner, the effect of detraining on specific running muscles has been harder to find.

However, the little research that does exist about detraining in general proposes that the most dramatic reduction in fitness occurs within a 10-28 day window. Before and after this window, detraining from a structural perspective isn’t severe.

Also, there is some research on how quickly use benefits from strength training (see our full write-up here). In short, most of the research shows muscle power declines significantly slower than metabolic factors.

What does this mean? After 7-10 days of not running, you will lose some muscle power and coordination, but not enough to totally derail your goals.

With a few specific workouts such as hill sprints, you’ll be back to your pre-detraining levels before you know it. If your break from training is longer than two weeks, than you’ll have a little bit to make up before you can get back to personal best shape.

What does it all mean?

Research shows you shouldn’t be too worried about losing significant fitness if your break from running is less than two weeks.

You’ll lose some conditioning in your aerobic system and muscles, but pre-inactivity fitness will return quickly. Again, this assumes that you have built a healthy and consistent base of training of 4-6 months prior to taking time off. It’s not the end of your career if you haven’t been training for this long; it simply means that the reduction in fitness will be slightly more pronounced.

After two weeks of not training, significant reductions in fitness begin to occur and you’ll have about 2-8 weeks of training (depending on the length of inactivity) ahead of you to get back to your previous level of fitness.

Basically, here is an easy to follow form chart:

Days of not running Reduction in fitness What this means for a 20 minute 5k runner
1-7 days Negligible reduction in VO2 max and muscle power Now running 20:10
10-14 days 6% reduction in VO2 max and minimal reductions in muscle power Now in 21:05 shape
14-30 days Estimated 12% reduction in VO2 max and decrease in muscle power Now in 23:00 shape
30-63 days 19% reduction in VO2 max and significant decrease in muscle power Now in 24:00 shape
63 days or more 25.7% reduction in V02 max and significant decrease in muscle power Now in 25:30 shape

RunnersConnect Master Extra

Had to take some time off recently? Download our one-of-a-kind Performance Decline Calculator to find out what your estimated performance decline would be for any race distance in your members-only download section.

Click here to access

Not a RunnersConnect Master member? Click here to learn more

By no means am I suggesting that taking time off from running is an enjoyable experience. However, sometimes it’s inevitable or for the best in the long-term. I hope this article answers all your questions in a practical yet scientifically supported way. Please feel free to comment and share with your running friends.

Now that you know that a few days off, how do you adjust your training when you need to take time off? Here’s an exact outline on how to return to running after injury, sickness or missing training.

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185 Responses on “Losing Running Fitness: A Scientific Look at How Much You’ll Slow Down When Not Able to Run

  1. So, I had to take 5 days off right before my half marathon this weekend and instead of working I decided to freak out that I had lost all my fitness so started going on a google spree to get some reassurance. Ended up at your article and started reading and was like, huh, this sounds like something Jeff did (12 miler with saran wrap). All of a sudden I look up and see your name and picture! So, thanks for the reassurance 😉 Hope all is well with you!

    • I either have a torn rotator cuff or it’s just sprang really badly since last wed. I have a half marathon with hills in Atlanta ga on thanksgiving. I’m nervous to start running again in fear that I will cause more pain to my shoulder and more time out of work and less time running. Any suggestions? Should I just go for it? I’m a 26 year old female that has been running for years and this is my first injury that had stopped me from running

        • Hi there, the participants in this study didn’t run, but did they engage in any other physical activity during this period? I ran my first half marathon on Saturday. I’ve been running for two years and four months now. I completed the race without any problems, but developed severe pain in my left ankle and sole of my foot that afternoon. I haven’t run since and I’m not really motivated to get on a bike or do any other exercise. Typical injury blues… Anyway, would my fitness take a severe blow if I take off an entire week, entirely without any form of exercise? Thanks so much for a great article!

    • I love running even though I feel then pain but it never stops me from trying
      I’ll prove all I can to do track I would get first and second in track it’s just a great sport to me

    • Glad the article helped, Eric. A few days off won’t do any damage to your fitness, but it should help get you healthy and ready to keep training consistently week after week. That consistency is much more important than a few missed days here or there. Good luck!

  2. Thank you so much! This makes me feel so much better! I am going to Hawaii during spring break, which I an still planning to run but I won’t have my rigorous track training! Thank you!!!

  3. Thank you so much, this helped me feel better as well- I’m taking a full week off in hopes my shin splints will heal and my marathon is 5 weeks away. I just hope a week off is enough to heal!

    • I am glad the article helped, Ellen. Hopefully, it puts some of those fears to rest. I have coached a lot of runners who have had some issue come up within the last 5 weeks and the race always seems to go pretty well once they get back on track. I’ll cross my fingers for your shins – best of luck!

  4. I’ll add my voice to the chorus, Jeff. This couldn’t come at a better time for me. I’m on my 6th, and final, rest day after a SERIOUS sunburn on an 18 miler last Saturday—ended up with pretty serious fatigue and nausea for the first part of the week. Now that I feel up to running again, I was starting to feel like I was losing fitness by taking this final day off. Glad to see that all the advice I had received from other is backed by science.

    I still wanna run today, though. 🙂

    • Thanks for chiming in, Mike. The urge to run never goes away no matter how well-informed we are. I am glad the article could help you feel a little more comfortable with the smart decision you made. Good luck with the comeback over the next few days!

  5. Thank you so much! I haven’t ran in 5 days due to exams and started feeling REALLY guilty. I am getting back into running tomorrow so I really want to thank you. Really well written out article (:

  6. Thanks for your advice, it was good to read your article. I have been training for Edinburgh marathon, My training was going great but then I had to go away with work for two and a half weeks. I did a very active trip to Everest base camp so lots of long days walking. I got back and had a chest infection so all in all not ran for about 3 and a half weeks 🙁 I am back running now but it feels do hard, I have the marathon in 4 weeks! Will my fitness come back? This is my 4th marathon so I run a lot 🙂 thanks zoe

    • Hi Zoe. Well, the trip to Everest, while you weren’t running, was probably fairly neutral in terms of fitness lost. Basically, the walking and the altitude probably kept your fitness stable – you didn’t gain anything but you probably didn’t lose much either because of the stimuli. That said, you’re probably a week behind. In my experience, you’ll feel pretty bad for 3-4 days and then you’ll have one workout in the 5-8 day range that finally feels like it clicks. At this point, you’ll feel back to normal and have plenty of time to put the finishing touches on your marathon fitness. To sum up, give it about 10 days I think you’ll be feeling back to normal. Best of luck at your race, I hope it goes well!

  7. ive gotten a knee injury and have already taken a 7 days off, and im dead in the middle of cross country season. Physio says it could be another 3 or 4 days.. so im looking at possibly two weeks no running, after running consistantly for about 6 months on high training. my regional trial dates are only 4 weeks away aswell! so even though this is reassuring that it wont screw me over too much, i will still have to work damn hard now to get where i want to be. Not sure if its like this for other people, but after 7 days of not running, my body is literally screaming for me to go for a run! cant wait to get back into it! thanks for this information.

    • Sorry to hear about your knee injury, Jordan. I know how frustrating it is to be right in the middle of the season and comedown with an injury. Hopefully, you’re back up and running in two to three days as the doctor seems to think. I went through a similar situation (my injury was closer to the big race) and things turned out ok: As I pointed out to a commenter before you, I think you’ll struggle for about 6-7 days and then you’ll have that one workout that really feels good and gets you back in rhythm. From there, hopefully you can build on your 6 months of good training and have a successful regional race. Best of luck!

      • Dear Jeff, your wise words are truly what so many of us hard-driving, super-expectation-holding, running-lovin’ competitors need to hear every once in a while. I am awfully glad to be reading not only your posts but also the posts of the other readers, with whom I share several traits. Thank you for your calm approach to what, for us, sometimes and illogically seems like the end of the world. 🙂

  8. Great information, Jeff – very encouraging to realize that one week off due to illness or work is not going to sabotage the training season!

  9. I love, love, love this article! One of the best articles I have read on the topic of detraining! Thanks for sharing your wisdom with us!

  10. Thanks for this article. I remember seeing it a couple of weeks ago when I first discovered your terrific blog and came back to it today because I have come down with some sort of upper respitory tract infection 2 weeks away from my second HM. I am becoming increasingly distressed at how this will affect my ability to run it at all let alone acheive my goal. I gather from the article and your post that the reason for the running break doesn’t seem to affect the performance reduction much – its the break itself (I hope so anyway)..

    • Hi Sam,

      Thanks for the compliments on the blog, I am glad you enjoy reading. I am really sorry to hear about the recent respiratory infection. Getting sick is no fun, regardless of the impact on your running. You are correct, the reason behind the break isn’t a factor in fitness reduction. The only caveat is that being able to cross train can take some of the edge off (Cross training vs. not cross training for 14 days results in a 1-2% difference: I don’t suggest you do any cross training with the infection, but just something to keep in mind should you run into the situation again. Best of luck and get better soon!

  11. I am so glad to have found this article! Three weeks ago I developed posterior tibial tendonitis, four weeks out from running the Gold Coast Marathon (now in 10 days time!). In order to ensure I make it to the start line, I have had to slash my running kms from 50-80kms a week, running 5 times a week for the last 5 months, to only running once in every 3 days, maybe 2-3 times a week max. I’ve made up the difference cycling and on the rower, also in the pool (I am also a triathlete), trying to replicate the missed running workouts, so both long, steady state and high intensity intervals, but the last few runs I have done I have felt Soooooo unfit. My HR has been averaging about 10bpm higher on my last couple of standard 10km runs at a pace which really should be fairly comfortable and now I am stressed I have lost all my fitness, with only 10 days until the marathon (my first). I had been feeling calm and confident about running a 3:30 marathon (my 1/2 mara PB is under 95 minutes) and now I am super stressed!

    • Hi Nicola, I am glad you enjoyed the article and do sorry to hear about your injury problem. Struggling the first few days back (up to a week) after an injury is normal as your body gets readjusted to running. However, you didn’t lose significant aerobic fitness, which is a big component of the marathon distance. While your build-up wasn’t perfect, I think you put in enough training to still run well. I have seen and worked with many marathoners who have had more severe cuts to their training in the weeks before a race run well. It won’t be easy, but hopefully the body of work you put in before the injury will carry you through. Best of luck!

  12. Finding this article has been such a relief.

    I am training for the Gold Coast Marathon. I had been training consistently for 17.5 weeks, and bam – hip injury. I went to the physio last week, who performed some miracles and the pain was gone by the time I hopped off his table. But the pain has returned (moreso when I walk than run, but it’s affecting my running gait), and as such in this last fornight I have slashed my training from 5-6 runs per week, to 2-3 per week.

    It is my first marathon, and I will be running it in five days. I am seeing the physio again tonight and I’m hoping I can get a couple of runs in before Sunday 1 July.

    I am quite devastated that four months of solid training, where it was really feeling like it had all come together beautifully, could come to such a screeching halt.

    I will be running the race, but am very concerned that I have lost fitness and muscle over the last couple of weeks. It was always going to be a challenge, but now it will be even more so with a sore hip and decreased fitness.

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  15. I found this article quite reassuring. I typically run 7 or 8 miles 4 times a week and have recently been sent out of town for work that requires me to be gone for 2 weeks at a time. Luckily this work shouldn’t exceed 3 months.

    I have to admit that I thought my fitness level was going to severely suffer. After I was gone for the first two weeks I decided to just do an easy 4 miles when I got home, 5 the next day, and then I kicked it up to 7 every other day from then on. Like you mentioned earlier, it seemed as though I had to get through 2 uncomfortable runs and by day 4 I was back on track. Muscle soreness for the first couple of days was the biggest issue. Does this sound typical?

    • Hi Dan,

      Thanks for sharing your experience. Muscle soreness and a little lethargy are common in the first few days after a brief time off from running. You should feel back to normal after that last harder run and be ready to start making positive fitness gains again.

  16. Thanks for the awesome article Jeff! Just curious, do you have a sense of how that reduction in fitness chart goes for runners that stop doing speed/tempo workouts (but still run easily almost everyday)? Or complementary to the article you sent out today, how fitness changes for a runner that stops running but instead picks up other cardio / sports / exercises? I’m assuming when the chart says no running it assumes no other activity as well…thanks so much!!

    • I’ve never seen any research that could answer this question, which isn’t surprising considering you can’t control the variables. In my experience, doing running or good cross training basically eliminates the performance decline. You won’t gain fitness if you do good cross training or easy runs, but you won’t really “lose” it either – it will just take a few runs to get a good feel back.

  17. Nice article Jeff, enjoyed reading it, i have a couple of questions if you don’t mind, ii haven’t been training for around 16 months due to traveling around for work (And smoking lightly at the same time), i built up a decent fitness before that by doing some 2 to 4 mile jogs and mostly interval training over 6 to 8 months, longest run was 10 mile, these days (Just started back 2 weeks ago) jogging around 1.5 to 2 miles in 15/16 mins and im still feeling as if im struggling after 2 weeks of running nearly everyday to do this 1.5/2 mile run – i guess it’s gonna take me much longer to get in the swing of things ? i had a glimpse of my old fitness 1 jog last week when i done 3.5 mile with ease but this little jog still feels pretty tiring :/ Thanks

    • Hi Keith, 16 months is a long time off/down – enough to bring your fitness back to 0 (meaning at not trained levels). In my experience, it takes about 1 month of running at about 25% of your normal volume to start feeling good again after that amount of time off. Given that, I think 1.5-2 mile runs will probably remain “difficult” for another week or two.

      My advice would be to start doing a lot of core, leg strength and hip strength work. This will speed the development of your running muscles. Then, you can push it on a few runs and try to go 3-4 miles at once every other day. It will suck and be very tiring/painful, but it will break you through the plateau and the strength work will keep you healthy.

      Good luck!

      • Thanks for your answer Jeff

        Yeah i just started some core training actually, will keep at it and dig in. hopefully see some light in the next 2 to 3 weeks 🙂


  18. Im panicked about running a relay next week because I have done more strength training than running. (Minor Injury) I have participated in Bootcamp which incoporates running including hill sprints. I ran my third Marathon at the end of may and am wondering I should take a pass. Its been 10 weeks since the Marathon. Any thoughts or advice for this week?
    Your article was really terrific but I wasn’t sure how much you would loose if you consistently did some of these other activities.


    • Tough question, Gina. There isn’t an “exact” amount of fitness you can calculate being lost when you’re doing other activities. Second, it all depends on what your goal for the relay is and how far the race is. If it’s 10k or less and you just want to finish, you should be ok. If it’s longer than 10 miles or you want to run a PR, I suggest you skip it. Also, make sure running won’t aggravate your injury. Hope that helps.

  19. Brilliant article, incredibly interesting stuff.
    As a 400m/800m runner, I heavily rely on track speed work.
    On the 16th of this month I suffered a hamstring strain and have required heavy physiotherapy over the course of the past two weeks. Its now getting to the stage I’ve been advised to start light jogging. My question however… It will be realistically 2.5/3 weeks before I’m able to start training properly again. Over this period of time, how will my speed/speed endurance have been affected?

    • Hi Ross,

      Sorry to hear about your injury. Unfortunately, the speed, speed endurance, and neuromuscular training is the first to go and most difficult to get back when you’re not running. I can’t pinpoint exactly how long it will take to regain your old form, but it won’t be quite as quick as it would be if you were training for a marathon. Good luck with the rehab!

  20. Hey Coach Jeff,

    My son is 15, ran 17:31 for CC last year in his first year as a freshman, and was doing well in track last year (4:45 1600 M, 10:15 3200 M by mid season) until a girl accidentally kicked his bare foot at the beach and broke his 5th metacarpal on March 23rd. Had to wear a boot for 10 weeks, was not allowed to do any type of cross training, so all he did was some core exercises. Finally allowed to start running June 4th after 2 weeks of walking without the boot. Was off for 12 1/2 weeks.

    Gradually built up his mileage doing slow easy runs and had the various aches/pains/stiffness that goes with being immobilized for so long. Worked back up to hitting 43 miles this week and feels well. Easy runs and long runs (8 – 8.5 miles) are pretty comfortable at 7:40 pace now (was at 7:05 when got hurt) and has been doing some hill work once a week, Tempo Runs, and strides. Started doing some good VO2 max Interval work at Vdot of about 56-57 past couple weeks and did first time trial on home cross country course today. Hasn’t run on course since last year so it will take him a little time to get used to the terrain again and times were a little slower than we expected based on training, but came in at 19:00 on the course (was shooting for 18:30 today)

    Plan on continuing to work his total mileage up to 50 miles/week with 10 mile long runs by mid September and maintain that mileage up until end of October when we’ll taper back about 30% and increase the intensity to prepare for 3 weeks of Championship meets.

    He’s still not back to his previous baseline fitness level and I know it will still take a little more time. Do you see anything that we could be doing differently to speed up the process a little without over stressing and causing injury? He really wants to set the school record as a sophomore as he goes to a small private school and the CC 5K record is only 16:34.



    • Hi Todd,

      First, I think you have a great long-term approach for your son. He’s very talented and your focus on mileage and building up his aerobic base is going to pay huge dividends down the road.

      As for when he will start to feel back in peak, baseline fitness, I think that will happen when his mileage stabilizes and he gets one or two more hard tests like the time trial. That, along with the workouts, should build him back to where he was before.

      As for helping the process along, one of the first areas to deteriorate when not running is the neuromuscular system. So, I would give him some explosive hill sprints 2-3 times per week after his easy runs. He can also start doing some drills and light speed development work to help along. If he takes enough rest after the speed development work, it won’t make him tired or peak too early. Here are some links that explain those concepts a bit further:

      Hope that helps and best of luck to your son this season!

      • Thanks for the helpful recommendations. I sent you an e-mail inquiring about personal training and look forward to hearing back from you

  21. Hi.. great article. I am training for Athens mararthon which is in 27 days. I have been diagnosed with FAI on MRI. I have not run for 2 weeks and after gaining as much infomation as I can, I have decided to run it anyway. I fear I have lost 2 weeks training at a crucial time and now have to plan how to tackle my milage most efficiently with the 4 weeks remaining. My last run was 20 miles – 2 weeks ago, which I felt great after – just a clicking right hip at times. It was many hours later that the pain set in, this was relieved with ice.
    Anyway thanks again, really informative.

  22. Hi Jeff,

    I have been training for a half marathon for a few months and had upto the 18k mark and was on plan to do it in uder 2 hours which is my goal. Went to a running shop for new footwear and got sold the wrong shoes. Long story short, very bad blistering consistantly after a few runs, and out of action for a while.Got the footwear changed and although things improved i had a holiday to go on and then a very busy period with work and a new born to deal with.

    I hadnt ran for around 3 weeks then got a 10k in (still on track for 2hr) and had another 2-3 weeks not running.

    The half marathon is in 4 days and I am really not sure if i should be doing it in fear of causing any damage due to lack of training, so would welcome any advice you could offer?

    After reading your article im feeling like I should be ok?

    Many Thanks oh and you are now bookmarked, great site 🙂


    • Thanks for the compliments on the site!

      My advice would be to focus on doing no harm. Meaning, you don’t want to do something to injure yourself during the race that forces you to miss running for time after the race. Start at an easier pace and then if you feel good the last 10-12k, pick it up and see if you can get under 2 hours. Listen to your body and if it starts hurting, slow down. Remember, there are always other races. If you can’t do it this weekend, you can get in consistent training and do it a month or two from now instead.

  23. Hi Jeff, thanks for the time and effort to post the information on detraining.

    I have been running consistently for two years with an average mileage of 30mpw this year. I started training for the Dublin marathon (takes place on the 29th October 2012) in June following the P&D training schedule from the book Advanced Marathoning. I damaged my rectus abdominis (lifting my 5 year old son) and as a result have not been able to run for three weeks (this is the forth). The injury is healing and I intend running this week end.
    I had been aiming for a 3:45 finish time, is this totally unlikely now? I’m 44 years old.



    • Tough to say, David because I don’t know your ability level. If 3:45 would have been a good run when fit, I think it’s unlikely coming off 4 weeks of no running. My advice would be to either defer to next year so you can properly train or just start and run easy so it’s not too much of a struggle and you hurt yourself more.

      Good luck!

  24. Hey Jeff
    Great Article, it was very informative. I am a junior in high school and recently I suffered a injury to my foot that has kept me from running for 4 weeks. Finally I ran in a 5k race today, and my breathing felt absolutely terrible throughout. I am a runner year round, my pr in the mile is 4:40 and I probably run around 30 miles a week on average. How long do you think it will take me to get back into good-pr shape.

    • Sorry to hear about your injury, Sean. I think it will take about 4 weeks to get back into PR shape. Two weeks will be a bit of a struggle and then things will start to click again. After that, you should start to feel normal and make progress back to PR fitness. Good luck!

  25. This is a very good read! Thank you for posting this. I will now be a follower.

    I have stopped running for 12 days now, coming from a flu. I’m no hard-core runner – trying to squeeze in my home-office schedule. I started running 5 months ago ( 2 weekday runs @ 5k each day; weekend long run @ 8-10k) and I’m 34. I did my first 5k last September 23 at 30 minutes, and 10k run last September 30 at 1:03. I continued my usual 5k run twice after that.

    The flu got me last October 9, and the effect lasted until yesterday (was a bit long as I still wasn’t able to eat well). Now I can be able to run again this Saturday, and this article gave me enough confidence, knowing that the 12-day setback will not hit me hard.

    I have a schedule 10k run this October 28, barely a week to prepare for it. This article gave me an overview on what to expect coming from a 2-week slump. After reading this, now I don’t plan on getting a PR for it, I just want to be able to finish it without getting hurt, and eventually get back to my pre-sickness training.

  26. Thanks for your article! Though I am at two weeks today with no running. 🙁 I did my 2nd marathon 2 weeks ago (3:45) and after, my right foot has kept me from running. I am working with a physical therapist. But I have been able to road bike and swim. 3 days of biking 1.5 hrs- 3 hrs and swimming for an hour twice a week. This should help me with getting my running conditioning back I hope. I had a 1/2 marathon that I wanted to PR (1:40) in two weeks, but I’m going to cancel that and hopefully be ready for the Vegas 1/2 in 6 weeks. I also have a Sprint Tri in 3 weeks that I am going to do, but not kill myself. Do you think getting my running conditioning back will be easier with my other sports? This is my first ever injury and its killing me not running. Thanks!

    • The cross training absolutely helps. These figures were for people who did nothing during those periods of time off. Studies have shown that aqua jogging can enable a well-trained runner to maintain running fitness for up to 4-6 weeks.

      In one study, a group of ten runners trained exclusively with deep water running for four weeks and compared 5km race times pre deep water running and post deep water running. The researchers found no statistical difference in 5k time or other markers for performance, such as submaximal oxygen consumption or lactate threshold.

      In a second study, researchers measured the effects of aqua jogging over a six week period. This time, 16 runners were separated into two groups – one who did aqua jogging workouts and the other who did over land running. Using the same training intensities and durations, the researchers found no difference between the groups in maximal blood glucose, blood lactate, and body composition.

      Good luck at your races!

  27. Hi Jeff –

    This is a great article and made me feel more comfortable about my training. I’m running the NYC Marathon in 2 weeks. It’s my first marathon. My training has been great up until two weeks ago after I ran my 18 mile long run. I finished the 18 fine, at my marathon pace, but the next day felt the effects of ITBS. Since that 18 miles run, I was only able to run 5 miles on Monday and 2 miles on Wednesday. The pain on the outside of my left knee was so bad that I’ve had to take a week and a half off. I tried to run twice between then and now but haven’t been able to make it past 2 miles without the same pain coming back.

    I’ve gone to my physio and he told me that with an 18 under my belt, I’ll be okay to run the marathon with some low mileage between now and then. But being my first marathon and my typical dedication to my training schedule, I’m so upset and am afraid that I’ll never see the Finish line.

    Any other thoughts/advice on this?

    Thank you!!

  28. very useful article, i was just looking for something like this to read.

    my fitness was at its best but at the start of october i ran myself into a triple stress fracture (sacrum and left and right pubic bones). so i cant even cross train. i am told it should completely heal by the end of the year which is a 3 month break. so now i know how much i will lose but it would be great if you had a table to show how much time it might take to regain the fitness.

    i am supposed to be running a huge multi day ultra at the start of march.this would leave me 60 days to get back to full fitness and have a quick taper. can it be done?

  29. I have been training for 22 weeks for the Dallas Marathon (December 9th), which is now 10 days away. Today is my 5th day off and I still have some slight pain in my knee (towards the front on the patella tendon), due to a 30 mile run last weekend. My most recent race was a 5k on November 3rd in which I ran 18:23. My plan during training had been to run 6:29 pace and finish in 2:50:00. I am curious your opinion if I should change my goal to something like 6:45 (assuming I can get a couple runs in next week to feel sharp) or still try for my goal 6:29 pace? I worry that going out at 6:29 may kill me in the end if I have lost any endurance during my time off. I’ve always heard that for every second under your ideal pace you run on the first half of a race, you will add 3 seconds above ideal pace on the second half. I do think 6:29 was my ideal pace before my 5 days off, but losing confidence the longer I sit on my butt. Your opinion would be greatly appreciated. Thanks.

    • Hi Joe,

      Sorry to hear about your injury. I would definitely slow your initial goal pace (6:45 sounds reasonable). If you get to half way and still feel strong, you can push hard and see if you can’t get very close to 6:30 average. By racing this way, you set yourself up for a better race and the opportunity to finish strong. You are correct, by starting too fast, you put yourself in high probability that the last 10k will be disastrous.

      Also, I would consider checking out this interview about why 30 mile long runs are definitely not needed (and often harmful):

      Best of luck and hope that helps!

      • Coach Jeff,

        Thanks for the quick reply and the good advice. The video was a helpful reminder that progress will not always be linear and that every marathon will not be a PR. My last marathon was in April at the Illinois Marathon where I set a PR of 3:04:35 to qualify for Boston. It’s possible I bit off more than I could chew trying to do enough speed work to drop my time to 2:50:00 and at the same time (neglected to mention this earlier) add enough distance to run my first ultra marathon (50 miles) on February 2nd in Huntsville, TX. The plan I’m following called for a 24 mile run, but since I was feeling good at that point and knew I needed to hit 30-35 sometime before my ultra I elected to keep going. It’s very possible I’ve ruined my chances for a good marathon with this dumb decision, but something I will learn from going forward. I’ve emailed my mom a link to the Hansons Marathon Method for a Christmas idea so hopefully I can use their program to get ready for Boston on April 15th and have a better build up.

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  31. Hi Jeff,

    Excellent article indeed, thank you! I’ve been running 4-5 times a week for the past year and half, pretty much non-stop (45-50 miles in the summer-fall, and 20-30 miles during winter-spring). I have/had been in very good running shape indeed. About two and a half weeks ago, I pulled my hamstring -a level one injury it seems. I took 3 days off running and then went out for 5 miles at a slower pace, it felt tight at mile one but I kept running through the tightness. I rested from running for another 3 days and then went running at a similar slow pace for 5 miles again, this time the tightness kicked in at around 2.5 miles. I have been keeping this same on and off system until two days ago and the tightness is still there, so I have decided to give it a rest and not run for 1-2 weeks. After reading a bit of literature on the subject, I am concerned that I may have delayed the healing process by being so stupidly stubborn. I am also concerned about losing running fitness by having limited my runs in the first two weeks after the injury to suspending it completely in the next two weeks. Do you think the combination of a badly rested injury plus limited or no running for a period of a month will have a very adverse effect on my running fitness? Either way, how long should I expect before regaining my pre-injury fitness -and will I achieve that given that I have not rested when I should have? Many thanks!!

    • Hi Diana,

      Yes, I would have to agree that you probably delayed the healing process a bit and extended the time away from running so that it impacted your fitness. I would expect about 3-4 weeks before you’re back feeling at your pre-fitness level. The first 3-5 days will be rough, days 6-12 are usually decent and you start feeling back to normal. Sometime between 12 and 21 days you’ll start to notice things click again and you’ll be right back where you were pre-injury. Best of luck with the rehab and comeback!

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  33. Coach Jeff,

    Great article … thank you for sharing.

    Question about coming back after time-off. To keep it simple, say one had consistently been running 1 hour 4x a week with alternative (non-running) activity on the off days.

    Due to injury, running ceased for 3 weeks but other activites continued while the injury settled-down.

    Now it is time to start back … how long and at what intensity is the first run and what would you propose as a rational build in hopes of getting back to regular running as noted above without significant risk of reinjury?

    Look forward to your thoughts to make the most of the time-off without going immediately back on the DL,


    • Good question, Steve. Always hard to suggest training when only looking at a glimpse of training, but I would do a week of easy running at about 50-60% of your normal volume. The next week you can get back to running full mileage. If you’re doing workouts, you can do something like 5x 3 minutes at 10k pace w/2 minutes running for your first workout back the third week.

      Best of luck!

  34. Coach Jeff,

    Thanks for writing such a great article! I’ve been out from running the past 3 days or so due to a stomach illness (tried to stupidly make up my 10mi long run tonight and almost got sick by mi1 hehe) and i was starting to get anxious. I had 2 coaches in HS for cross country that always guilted everyone if they took a few days off due to illness or injury, stating that all out hard work was gonna be gone, so old ideas were stuck! Thanks for clearing so many misconceptions up. It really helped.

    Hope you’ve been having a great start to the year!!


  35. I am 16 and I usually run 2 miles every day for fun, not for anything specific like a sport or anything. I also lift weights. If I take two days off in a row every now and then will that ruin my conditioning? I keep stressing because I am trying to put on muscle but I want to keep my conditioning too.

  36. Hey, I like the article but I’m one of those irrational freaks who can’t stop no matter what. I am 10 days away from a half marathon that I’ve been training pretty hard all winter for. The damn flu got me over the weekend and, since this is my peak training week before a short taper I ran 11 miles in the cold anyway..I managed and then took my normal Monday off..Tuesday early morning when the flu was probably at its worst I forced myself up 5 miles of mostly hills, running slower than I thought I was even capable stupid as it sounds, I was humiliated…Tonight was my last speed workout and I managed to nail 10 x 400’s at 5k pace, but I puked in the parking lot afterwards…due for a 3 mile pace run and a 12 mile long run this weekend…at this point I’m mostly concerned with getting my energy back as the actual flu seems to be receding a bit but my usual crazy metabolism seems shot…what do you recommend moving forward? I want to pr next weekend (half marathon)

    • You’re not going to like this solution, but I suggest you take a few extra easy days and maybe even a day off. Running hard isn’t making you fitter right now, it’s actually making you a slower runner. You’re not recovering and thus you’re not making progress. The best thing you can do is rest. If you want to PR next weekend, run short and easy through the weekend and do a moderate/easy workout next Tuesday. Have the courage to give your body what it needs to race well, not have an impressive training log.

  37. I had to take a week off because of dengue fever, for who doesn’t know it’s a third world country disease caused by a mosquito bite. Aside from the fever and headaches you get real bad muscle a joint pains…It was the worst 7 days of my life…but today is my 5th day back and I’m already up to 13km, I started back by running 9km and a a km a day…I’m slowly getting my resistance back up as for speed I know that will take a bit longer…

  38. I was worried when I got injured as I had to take 6 weeks off with no exercise. When I started back I was amazed how much of my fitness remained. I was running 6:20 pace over 6 miles before injury, first run back after 6 weeks off I was running 6:50 pace. I would have thought the fitness levels would have been much worse. I had been running for 2 years continous before injury.

  39. Super worried about my highschool runner. She was in great shape for the 2012 XC season, ran all summer and looked really strong. However, when the season started she kept losing ground, said that “she felt that her legs were heavy”. We had her iron checked and it was really low. Finally by the end of the XC season she was coming back and did very well at State Finals. However, over the winter she really lost interest in running all together, I could not encourage her at all to run to stay in shape for track season. Track season is now here and her 5:10 mile time has increased to 5:45. Will she bounce back to her 5:10 time for State Finals? She seems to have no desire to run at all anymore. Ugh..I don’t know what to do to encourage her anymore. Any suggestions?

    • Sounds like your runner might be overtrained, in addition to low iron. You definitely can’t force someone to have passion and desire. Sounds like she could really use some downtime to refresh and recharge her batteries. My advice would be to make running fun again and forget about performance. She is very talented, so the performance piece will always be there. Here are some good resources on overtraining and low iron.

  40. I have been training for half marathon for the last five months. The race is in three weeks I run 30 miles a week. I have not been able to run for six days due to injury in my calf muscle not sure what happen. I did 11 miles on Saturday and Sunday during my run my left calf started hurting so bad I could not finish my run. I am 54 years old and have been running for 35 years need some advice.

    • Sorry to hear about your injury, Dusty. My recommendation would be to take this next week entirely cross training and working to get the calf 100%. If you can start running and still have 10-14 days to get your legs under you, the half marathon should be ok. However, the most important thing is long-term health. If you take the time off and the calf doesn’t improve, my suggestion is to forgo the race, continue to cross training/therapy until you are 100% and then slowly get back into training. Hope that helps.

  41. Hi-
    Thanks for the helpful info in this article. I am 36 yrs old & have been a runner for over 20 yrs. I have recently been diagnosed with Lyme’s disease and was told that I should not run for at least the next month. (Supposedly my body can heal faster & fight the infection more efficiently if I decrease the intensity of exercise. ) I have the green light for walking & yoga. That’s it. I’m only a week & a half in & I’m going a little crazy, both physically & mentally. Your article has helped, but I’m still worried about losing the fitness I now have. Can you suggest any good, efficient walking workouts? Or other low pact workout so I can maintain some level of fitness? Thanks again for the insightful article.

    • Hmm, I don’t know any more efficient walking workouts – there is sort of only one intensity for walking. However, your main concern should not be on losing fitness right now. The faster you can recover from the Lyme’s disease, the faster you can ultimately get back to training and running well. The very slight fitness you can get from doing intense walking or low impact workouts is not worth the potential time it may setback your recovery. Hope that makes sense.

  42. Hey Coach Jeff! I just ran a 50 mile race 5 days ago. Unfortunately, I did something to the outer ligament of my foot either during or after the race. I took 2 days off and then tried short runs, in which I experienced intermittent pain. I guess I’m wondering how to know if you can run through pain. Should you never run through pain? Or is it okay, if the pain subsides at some point during the run?

    I am running (well, I’ll be walking a lot too!) a 24 hour race in 3 weeks. I’m afraid if I cut back too much, I will have a hard time completing it. But I’m also afraid if I run on an injury, it won’t get better by race day.


    • Generally, you should never run through pain. Sometimes, you’ll have tightness when you start a run, which is ok to work through if it gets better as the miles go on. However, pain will almost always get worse as you go. I know it’s hard to cutback and get healthy, but the long-term benefits pay off more than the small amount of fitness you might lose. It’s better to take a week off and be 100% healthy and get back to hard training than try and run through something and needing 3 weeks off later. Best of luck!

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  44. Jeff, I ran a 1:33 hm 5 weeks ago. After that my calf/achilied got real sore. I continued to train until last week where I was only able to get 10 miles in. I haven’t ran in 5 days. Today is wed and another HM in my town is Sat. Thinking of going for easy run tonight and if all feels well try it on Sat. Will I see major effects on my time. I normally run 35 miles a week for last year 10 miles 2 weeks before race only 5 race week…been running for years though.

  45. Hi Coach Jeff,

    My daughter had a hamstring injury during track and took 2 weeks off running, but swam to keep cardio up. She was able to finish the last half of the season and trained hard. Do you think she should take any more time off before beginning training for cross country?


  46. One also has to address the age factor. Right now, I’m 64 years of age and have been running for more than 48 years. I have raced from 1 mile to 50 miles and trail runs to mountain runs. Throughout my years I have had a lot of injuries and learned well by them. I have had long layoffs and short ones to, but because of my love for running, I’m still running to this day. When I was 61, I was still covering 5k runs under 20 minutes, but because of the training it takes to maintain that speed injuries became a big issue with me and I had to back off the speed work and tempo training and in doing so I lost my sharpness. Since then its been all up hill for me and getting tougher and all those injuries I had reappears and keep me from the training I would like to do. As we get older the body parts get harder to recoup and mend and I’m in that stage right now.

    What am I doing about this problem? I’m reducing the mileage and not running speed work or even tempo pace and allowing the races to be my speed work. I do try to work on a steady pace training. For example, 3 miles at 8 min pace 4-5 miles at 8:15 pace and I’m trying to get myself down to down slowly by work on my pace effort .

    Right now my Achilles Tendon (both) have been treated in the past 4 times and there will probably go for the 5th time. So its a never ending story as you get older, but if you run a lifetime like I have then you have to adapt or stop running and I hope you have a high tolerance for pain as you will need it as you continue to run and age with grace.

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  48. This article has put my mind at ease about taking a much needed 8 days off of running. It works out to be four days because I’m in the last to weeks of marathon training.

  49. Firstly I´d like to say what an excellent article!

    Secondly I hope you can give me some advice please…

    I´m preparing for a 1.5 mile run test.
    My time was 9:30 for the full 1.5 miles (after a 1.5 mile warm-up that normally took about 12:00 mins)
    Ive been working on this specifically for about 9 months, doing the test every 2 months sometimes more.

    Running only 3 times a week to allow muscle strength to build I did:

    0.5 mile intervals at my fastest pace reducing the rest period each week
    6 x 1:30 hill sprints with 2 min rests
    50 minute run at a steady pace/165bpm average HR (6.5 miles)
    I did hill walking with a pack, swimming, boxing and circuits on my days off from running (I need to be good at multiple disciplines for the army)
    I always warm up and cool down, stretch with all of the above.

    I know 9:30 for 1.5 miles isnt that fast but short distances arent really my thing. Fortunately for me that time was good enough.

    Unfortunately I bruised my ribs sparring and I´m now on week 3 of recovery.

    Ive did a couple of technical boxing sessions on pads etc around 145bpm for an hour each 2 to 4 times a week for the first two weeks. Only certain movements cause it to hurt, unfortunately all my other activitied caused it to hurt, particularly running.

    Ive finally accepted that its not going to heal properly unless i take time off completely from all training as I was advised initially! (well… it is a bitter pill to swallow!)
    I think I will be able to run again at the end of next week.

    My question is if i have only two weeks to prepare for the real test what is the best plan to follow? Any ideas please?


  50. Thank you for this article – I have a nagging hip flexor injury that I have been trying to run through. I’m going to take a week off (family vacation) and then ramp back up.

  51. This is very interesting! I have been down to running just once or twice a week(generally a ten mile run), due to work, for the last eight weeks and have been very concerned about my fitness level.

    When I do run, I don’t notice much of a difference in endurance, however, I do feel as if my body has gone to mush!

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  53. Hi Jeff,
    I’m a senior in highschool and have been running for four years now. This summer I received the opportunity to go volunteer abroad for 16 days but looking at the schedule there is little to no free time to go running. Although we will be doing many active things there, I’m afraid of losing years of hard work considering I’m not a “natural” runner. Are there any quick exercises or short workouts that you recomend that I do there to minimize the lost of fitness? Also so body type play into the amount of time it takes to regain fitness? I only have 4 weeks after the trip to get back into shape before school sports start up.

  54. Hello Jeff, Great article. Questions for you.
    I ran a marathon in May 2013. Ended up with a minor calf strain a week later. I am taking 6 weeks off to make sure its healed up. I have another marathon in January 2014 6 months away. I start running again in August and my marathon program starts in Sept. How long do you think it would take me to get back into my pr shape before I start my training? And should I go with a lower volume plan this time coming off an injury or can I resume my same plan?

  55. Hey Jeff,

    I’d be interested to read a similar article look at the decrease in MLSS. VO2 max is all well and good, but we know it’s not the ultimate measure of endurance fitness. I would wager that there’s a much more significant decrease in the Maximum Lactate Steady State. But thats total speculation, i’d certainly be interested to read anything you’d have to say on the topic.


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  58. I am 19 years old and have been running for 30 to sixty minutes nearly every day for the past 4 years. I have been hospitalized to gain weight and break bad habits as I have anorexia. I am confined to almost bed rest but have been doing as much muscle stretching and body weight exercise (plus jumping jacks, burpee’s etc).
    Firstly, I am concerned at how much running fitness I’ll lose, particularly cardiovascular and am I at risk of injury upon returning? Are there any beneficial exercises I can do to maintain my running fitness as much as possible?
    Any other relevant advice would be appreciated! Thanks!

  59. Hi Jeff,
    I’m a 15 yr old boy and I’ve been running for about 3 yrs, 2 of which I’ve done cross country and track. I’ve recently gotten the opportunity to go to Australia as part of a student program. I’m looking at the schedule (2 weeks) and I don’t have any time to get in a run. I’m worried that this is going to affect me more than you said because I’ve worked extremely hard to get into the form I’m in now (4 yrs ago I was kinda fat and didnt run at all, now I’m really skinny and can run pretty well for a 15 yr old) cross country season is a month away and I’m worried about how this trip is going to affect my fitness.

  60. Dear Coach Jeff

    Excellent article. I have been trying to improve my pace and thereby PR (current PR -3:50 April, 10K 45:30 in July 31) and have been working with a plan that peaks me at 65miles/week with appropriate speed and tempo works. I have been clocking 57m for the last 4 week and have developed a slight soreness in the left foot upper ankle and this week have lost it mentally to put in the hard yards this week.. your article is reassuring in that I may not lose much fitness, but nevertheless do you have experience with this upper ankle soreness with your trainees and what are the issues with a 50%drop in mileage? Advice greatly appreciated and thanks to you for serving the running community with such great passion and insightful blogs

  61. Thank you. I found this article made me relax, I did a half marathon race last weekend and have an old achilles problem come back. I’ve been in pain just to run 6 miles and have pushed myself all week to the point of tears. I have Blackmoors Sydney Marathon in 3 weeks and all I’ve thought about is I wont be able to run. This is my 15 th marathon, Im used to odd knee pain but achilles tendonitis is one of the most awful injuries I’ve had to endure. Im going to take road bike out, relax and get back out again once the swelling and pain has gone down. Thank you again. Kath

  62. I have been training for my first marathon and got the flu, unfortunately I also picked up a chesty cough which has impacted my breathing. I haven’t run for 16 days but had been running 40 + kms a week for at least a month before that. With 5 weeks before my marathon I’m very concerned I would have lost too much to get back to training and finish the marathon. Have I lost too much to continue?

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  65. Hi Jeff! Quick question– so I strained my hip rotator cuff which is preventing me from running for the next few days, but I am able to bike and presumably swim with no pain. However, my physical strength is much weaker than my cardio in those activities (i.e. my legs start burning way earlier before I even get out of breath when I’m biking). Do you have a suggestion on how to maintain cardio shape, or am I just being a wimp and should push through the burn? Brent said running in the pool, but I have never done that before!

    Any advice would be so greatly appreciated!!

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  67. I’ve was injured for 3 months. My best 5k was 20:12 and after 3 months of not running my best dropped to 25:10!! My 20 min run was achieved after 6 months of interval and speed training. Will it take another six months to get my VO2 back to normal? am I starting from scratch again?

  68. Jeff,

    I have my first half marathon coming up a week from Sunday (9 days away). I have been running 4 days a week since July 1 and just ran 12 miles over the weekend. I have developed what a PT told me is “Runner’s Knee” in both legs (because of weak quads) and am worried about the injury keeping me from finishing the race. At this point, with the goal of just finishing, would I be better to run a few 3-milers next week to maintain cardio and muscle or completely take the week off and let my legs heal?

  69. Im due to run my first marathon in 8 days and have a sore calf – getting better after a couple of no run days. Should I wait till next Sunday to race rather than risk further injury? The guilt of being inactive is a hard one.

  70. Hey Jeff-
    I’m coming off race season, beginning my fall fun runs and winter taper. I typically log 20mpw and after a bout of PT last spring related to a baker’s cyst, I significantly improved my gait and speed. I came off this season high on speed & competition, feeling confident in my plans for next year (a few halves, a Ragnar in June, a Sprint tri) by working on muscle imbalances and swimming this winter, reducing running to 3x per week. I am working with a wonderful team of orthos & chiros, but I have either sustained an adductor or biceps femoris strain, possibly even a stress fracture mid-run during a 7mi fartlek last week. I’m freaking out. I worked so hard over the last 10mos to get to a place I didn’t know I was capable of at 33 & 2 kids. I want to be ready for my Ragnar in June 14 most of all… can you give me hope?

  71. I have to rest for 3 days after my cross country season ended but I am continuing to run after that to stay in basketball condition. Is taking 3 days off from running going to affect my anerobic and arobic conditiong?

  72. Hi Jeff,

    I’m a 7 time marathoner (3:18 average) and train with a coach running 60-70 miles per week on average. I did Boston and San Francisco this year and was training for Philly (next weekend) when I came down with a nasty case of PNF/Runner’s Knee in early September. Other than a week of running in between when things were slightly better (but then it came back), I had to take a break and very begrudgingly table Philly Marathon. I have, however, been cross training every day. I swim between 5-7,500 yards/day, aqua job, as well as lots of agility exercises, muscular-neuro firing to help equalize strength out on both sides (left side being weaker than right seems to have caused imbalances which leads to injuries), tons of core work, flexibility work, and light light weights. I was a competitive swimmer for 10 years so I train doing all the interval sets I used to do and alternate strokes as well. Now that I’m feeling better and ready to start training again, can you give me an estimate as to how much fitness I lost and if you think I can come back relatively quickly, assuming that I’ve worked so hard to stay in shape and have years of experience and training under my belt? I have Miami ING Marathon on Feb. 2nd and am still hoping for a fast and strong race. Thanks so much,

  73. Hi Jeff, thank you for the great article. I’m doing my second HM in 3 days. I had been training nicely for about 5 months, and about a week ago I came down with the flu. I thought this was going to last only 7 days and that I was going to be back on running this week, however, I’m still feeling sick. Because I was freaking out that I was not trainining in my tapering week, I did a 5 miler 3 days ago, and some hills today. Is this wrong? Should I be resting instead of forcing my body to get it ready for race day? Now that I read your article I think it’s better to rest than force it. Is that correct? Thank you much!

  74. Hi Jeff,
    I’ve read this article in the past, but came across it again today while reassuring myself that I can take a week off. I have an inner-side-of-the-foot soft tissue injury and against my better judgement, ran 19 miles on it a couple of days ago. Of course things got much worse… but I was worried because I am 5 weeks out from my next marathon. I have my last 20+ mile run scheduled in 5 days, but I may have to skip it. I wasn’t starting from scratch, but “jumping off” from my last marathon in December. I hope I can still take a week or two off and be fit enough to run on March 9. I am a 30 minute 5k runner (5 hour marathoner), so I hope this information still applies to me. I run 30-40 miles a week. Thank you for the article.

  75. Hi Coach Jeff!

    Thanks for the article, great read. I have my first half marathon in three days. I injured my knee about 5 weeks ago on a 9-mile, long run. As a result, I was only able to run 20% of my training runs since the injury, with no long runs. During the most recent runs, I’ll have some slight pain during the first mile and it kind of works itself out. I’m doing this last week’s 2-mile training runs and it pains me that I’m not running them as effortlessly as I did prior to the injury. Overall, I would obviously have a better fitness level if I trained the last 5-weeks, but I’d say I’m in decent physical shape. Prior to the energy, I trained for 10 weeks.

    My initial goal was to finish the race in 2-hours. My confidence goes back and forth every other day. At this point, I have every intention of running the race and am strongly considering attempting my original goal of 2-hours. Is this unreasonable?

    Thanks in advance!

  76. Hi Jeff
    I run 1.4 mile every day and I will be going on holiday for 7 days and will not be able to run, I was just wondering how this would effect my fitness when I return from holiday and start running again?

  77. Hi, i’ve been training pretty solidly for a marathon which is in 16 days. Due to some unfroseen circumstances, after running my last long run of my training (20 miles) exactly two weeks ago, ive not been able to do any more runs. I will be doing a 16 miler tomorrow, but im worried ive damaged my fitness too much for the real thing in two weeks. What do you think?

  78. Very helpful article, but I do have a question. How easy is it to maintain fitness? I’ve been out for about a month, but I haven’t been completely “inactive”. Before getting hurt, I would be running 6 days a week. When I was “on the bench”, I would bike 3-4 days a week for 1-2 hours. Did I lose any fitness? If so, how much? Thanks for your help!

  79. Hey, this was a very helpful article, thank you! I recently tore my plantar fascias in both my feet and have been advised by a physio not to run until my next race, which means about two weeks of inactivity. Its just a simple 2km race, do you think my time will be significantly affected? Sorry I was just a bit concerned because my closest competitor is pretty close to me in terms of fitness so every minute counts. Thank you!

  80. Thanks so much for this post. I’m a sprinter and I had to take a day of because my shins were sore. I had some paranoia that I would loose some of my fitness level. So thanks again 🙂

  81. Hi, I have been running 2 long runs of 9-11 miles a month now for about 7 months with mini runs in between… My last long run was March 29(11miles) I hurt my ankle/calf. They say posterior tibial tendinitis but not sure… I ran a few 6 milers in between until two weeks ago.. I have done no running just swimming and biking… I have a half marathon in a week….what are your thoughts… still hurts when I run but I am still going to run it…. My goal was a 9:18 min mile….. What do you think I will end up Nd will it be tough for me to just finish

  82. I also have a case of tendonitis on the inside of my left ankle which popped up about 5 days ago. I have been training for my first marathon which is 20 weeks away. I started running 2 months ago and feel I may have went overboard and pushed up my mileage too quick (I was up to 27 miles per week when this condition occurred). I have not ran now for two days and have been doing ice, stretching and strengthening excercises. Im 42 and am worried that if I take a week off I am really setting myself back. Whats frustrating with this injury is that it doesn’t hurt when I run! Only when I am walking or standing after a run. What is your opinion, do you think i should I be running thru this to keep fitness up due to my age worried im losing my aerobic level. Your article is great and would love to hear further thoughts. Thank you!

  83. A good article, I started a dose of patella pain 2 weeks ago. I am supposed to be doing the Gold coast Marathon on 6 July but this is now in contention. I tried a run two days ago but knee said Nooo! so after 450m i turned back for a total of 890m. I was doing some DWR and swimming but after a trip to the Physio yesterday he advised me to give it total rest for a week keep swimming using a leg float for fitness. I have just under 3 weeks before the Marathon so if it comes good with rest in the next week two or so i think I will still have the fitness to run with all the swimming im crazly doing. My only concern is the deconditioning from not running… any thoughts on this Jeff?

  84. From my experience, sometimes nearly a full week off can actually help in the long run. Your body is able to recover from all the little things we learn to ignore when we first start distance training and no longer notice. In a week a person who was putting in even twenty miles a week before will not notice a significant drop in fitness and within a couple weeks may actually see a gain from it if it’s been a while since they have given their body a rest.

    I’ve recovered from a few injuries and a few just let my mileage drop for quite a time. Thing is, after training for years, your body has a base that decreases gradually. You will have to build back slowly, but it won’t be like you’re starting over. Your body will remember what it takes and it comes faster than when you first started.

  85. I’m so glad I found your article, thank you so much! My 4th marathon is coming up in 10 days and now I got hit by whatever the virus that’s going on!! I’m in the tapering period, but even so I’m freaking out from not be able to get those final stages of running in. I was thinking about pushing in 6 miles this morning but I just couldn’t, and trying to find the justification that it was okay to miss the run. Now I feel tremendously better that it was fine to take a day off, and maybe anther couple of days off .. hopefully no more than that!

  86. I’m a beginner, this will be my 1st race, been training for weeks for a 10k (absolutely loving it), the race is in 5 days, but I’m suffering from pain in my Achilles. I have one training session which consists of a 5k run left before my race, should I continue with the training or rest up for my race? I’m paranoid about missing my training in case it effects my race. Thanks.

  87. You’re article did not completely answer my question I quit running for a few days while before that I was training a little bit lighter than normal and I would normally run 5 miles and before that I was running 2 miles and now I can’t even run a mile and I run pretty slow now! So do I just need a few weeks of hardcore training or did I just mess up those 7 months of my life?

  88. Hi I ran The Chicago Marathon (3h: 16m: 37s), since then I have been training fore another marathon on the 16th November (5 weeks apart).
    My training schedule has been light: a couple o 6 milers during the week and moderate long runs (10 miles, 12 miles, 10 miles), on the weekends.
    What can I expect of my performance on marathon day.
    Thank you

    Rogério Calvo

  89. I don’t agree with the time off affecting your running. I ran my 1st 5k Oct 4th 2014. I got a time of 22 minutes. That is 7:09 min. miles. I did not run at all 10 days before the race. I don’t remember but I think I rode a stationary bike 2 or 3 times at a moderate pace for 30 min. I had been running constantly every day to few days depending in my schedule well over a year before this time off. I usually run between a 7:30 to 8 min. mile usually around a 7:30 min. mile. So at 7:30 min miles my 5k time is 22:63. Take into account a 6% reduction so my 5k time should have been in the very high 23 min. range almost 24 min. Instead I gained time. I think the fact it was my 1st race got me running faster due to the excitement. All said taking time off every now and then is a good thing. Keep in mind I am 27 years old. Might not work for someone older than me (someone past their 20’s).

    • That is true Kurt. Thank you for your input, and your body is most likely able to handle adversity more than others due to your age. We definitely agree that time off is a good thing, especially after a big race. We have posted about this in the past, and I think you would enjoy reading about it. Congratulations on your time though, that is a great result, and yes, the adrenaline on race day will definitely allow you to run a lot faster than you usually are able to, even in workouts. That is the beauty of racing! Keep up the good work, and thank you for your thoughts!

  90. Thanks for the article. I’m entering the final stages of Jeff’s sub 3:30 marathon training plan, and I’m a pretty structured individual. As such, I hate to miss workouts. But training in the winter is making the mid week runs tough because of how long they take (like tomorrow’s 2x5mi run). Between work, picking up the kids, and everything else, it’s tough to run during the daylight hours. It’s comforting to know that I can miss a workout here and there and not see a loss in training.

    That being said, my question is in regards to the type of workout missed. I’m in week 13 of the 16 week training plan, so I’m almost in the taper phase. If I’m missing the 2x5mi workout (an interval workout), should I just skip it or try to do it later in the week? My legs could use the rest, but I don’t want to lost the benefits of interval training. I guess my question boils down to whether or not it really makes a difference if I miss this one run in particular? Thanks

    • Hi Jeff, it is nice to hear you enjoyed the article, and you are enjoying the training. If your legs are really fatigued, to the point of where you are concerned that you could be close to an injury, it would be better to skip the workout. You could push it back a day or two, but if you are still not feeling any better, it is safer to make sure you get to the start line healthy by being a little conservative. Hope this helps! We will be behind you all the way!

  91. Hi there, thank you for the article. I have been going through this fear of losing running fitness and this article is so timely.

    It does make me feel more worried about my situation: I am a long distance runner and early October I developed shin splints on the left leg. I stopped running altogether and did pool running, elliptical and weights and lots of stretching. I have a very good sports doc and the xray did not show any fractures. It has been more than 2 months and i still have not run because theres still some discomfort in my shin and also in my glute – if it does not go away i will be getting another MRI to see whats going on. Basically it’s been 10 or more weeks from no running.

    I have to say that it’s been very very hard. I really dont enjoy any other sports than running. I live in NYC and its making it so hard not to run (i have been running about ~60+ mpw for a long time)…
    Today i did 1 hour light elliptical (the workout of choice for a while to ensure no other injuries) and i realized that “ive had it.” I am very scared of losing all of the running fitness altogether.

    I qualified to run Boston in April and it makes me so sad to be in this situation….Thanks for reading my ramblings.

    • Hi Nino, of course. It feels good to get it out sometimes, and there is nothing wrong with that. It is one of the best ways to come to terms with what is going on. It is good you are on top of your therapy and seeing doctors. It is never easy to take time off, especially when you do not know when it will be ready to run again. However, your perseverance, and listening to your body will pay off in the long run. You will have an extra determination when you are able to run and race again. Do not get discouraged. This post may also make you feel better

      There will always be another race, and if you qualified once, you can do it again! Stay positive! Hope this helps!

      • Hi Coach Tina,

        Thank you for your response, it makes a difference to share it with fellow runners, especially you guys on runnersconnect.

        I think i am losing hope that i will ever run again. It’s been too long and it’s tough. I will try my very best to get through it.

        Thanks again and happy running!

  92. Interesting and informative article. One thing I didn’t see touched on is anything about how age might affect these various percennt losses due to ‘detraining.’ Should us old coots (let’s just say on the generous side of 50 🙂 ) look at this differently at all? I have been delaing with runner’s knee for months, with various breaks in running of weeks. Currently going thru a fairly concentrated chrioppractic regimen to break up some calcifications in the patellar tendon. Chrio said for best benefit no running or cross training. So will end up having taken about 2 weeks off. And my ‘base’ prior to that was impacted by running with the soreness and having to skip sometimes due to work. thx.

  93. For periodization in training, I haven’t run since November 1 as I am focusing on strength until March 1. About how long will it take for me to regain my 100% VO2 Max once I begin running/conditioning again?

    • Eric, it would be impossible for us to give you an exact number, as it will depend on your individual differences, but the chart in this post should give you some indication, hopefully that helps!

  94. Hello, one thing I have been doing for a couple of years now, is taking 30 days off in the winter (mid Dec to mid Jan) after the fall marathon season and then another month off at the beginning of summer (june-ish) after spring marathon season. I have not been injured in a while but I am wondering if this is too much time off. I am trying to BQ. I have made progress over the years. Going from a 4;32 marathoner in Oct 2010 to a 3:42 in Oct 2014. I need to get below 3:30. Still I am wondering if the 2 months off which I do to mentally & physically rest hold me back as well. Thanks.

    • 30 days may be a little too long each time, maybe you could try 10-14 days instead. You have made huge jumps, so if you feel like it works for you, then stick with it, especially if you need the break mentally. You will probably find that 2 weeks is enough time to recover, especially if you take the first few weeks returning to running as easy, base building. The faster you get, the more difficult it is to improve, so that extended time off may begin to hinder you. Hope this was helpful! Congratulations on all your accomplishments!

  95. Hi I’ve been training very hard , every day for the last few months to get a new pb at the national indoor rowing championships. I need a good time to get on the national squad but a week and 5 days before the race I caught a flu. I’m now a week and 2 days out and symptoms are nearly gone just a bit of a pain in my stomach. Should I get back into training hard tomorrow? And will I have lost strength and fitmess because of the illness and few days off that will stop me from getting a pb?

    • Daire, that would not be a very good idea so close to your competition. Your best bet would be to take it easy for a few days, with one harder workout about 5 days out, nothing too strenuous, but to get your heart going. You will not have lost all your strength, as this article shows, but if you jump back in too quickly, you will put your body back in a bad place. Good luck!

  96. Hi, i have not ran since late november, early december. i was running for my college and my fitness level was at its peak, i was able to run a 4:30 mile. however i got injured in late november and when it came time to come back to running i was very demotivated. it has been a good 5-6 weeks since i ran seriously, i say seriously because i ran a few times but just couldnt manage to keep a consistent schedule. However i have been running now for 1 week straight, i was wondering how long do you think it would take me to get back into the shape i was in before. or atleast close to my peak form.

    • Hi Harold. Your coach is probably the best person to talk to about this, as he/she likely knows you and how you are able to bounce back after time off. It is difficult for us to calculate it for you as an individual as we do not know enough information about you. You are best to follow your coaches instructions (being honest with him/her) and you should be able to come close to your fitness in the outdoor track season.

  97. Hi – I am running a marathon this coming Saturday and I haven’t run since 2/22/15 when I experienced extreme knee soreness on a 4m run the day after my last long run (16m) before tapering. I cross trained vigorously (via HRM) for the equivalent duration that I would’ve normally been running (treadmill incline, waterjogging, elliptical, some cycling).

    Now, I’ve been given the clear from the doctor to give the marathon a shot. I plan to run a short one tomorrow (Thurs), and then rest the following day before the race.

    Originally, my goal was sub 3:10, but now I don’t know how to adjust my goal, if any. Should I back the pace off due to loss of fitness, or since I did all that cross training, should I still go for my goal?

    This page (and all the comments/responses) has been very encouraging, thanks in advance!

    • Hi Brian, sorry to hear about your knee soreness. It would definitely be a good idea for you to readjust your goal, it is great you did the cross training, and that will certainly help, but it is the pounding and the impact that your body will be a little unprepared for. You would be better off going off extremely conservative. If you feel great around 20 miles, then by all means work your pace down, but at this point it would be best to just approach it that you are happy you can even run it at all. Hope this helps! Best of luck!

      • Thanks, Tina. I guess I was hoping for better news than that. After reading Jeff’s article I was encouraged, but I didn’t realize I would lose so much in less than 2 weeks to the point that I should just turn it into an easy run.

        • Sorry if I confused you Brian, I was not meaning it should be an easy run, just to be conservative the first half to see how you feel. Especially if you are still being cautious with it. You have not lost your fitness, that is definitely still there, just want to make sure your body can handle the pounding and the intensity. It is your choice, but that is my best recommendation. It would be better to stay controlled the first half, then work your way down if everything feels okay, rather than going from it from the start, and as your body fatigues, your pain comes back, and you are not able to finish. We wish you every luck!

  98. I had a low back/butt injury that left me out from running for 4 weeks then I slowly got back into. I was able to start a 12 week marathon training program leading up to Boston and all was going well until Saturday when I woke up and the injury was back, not as serious but still hurt to bend. I went out for my 22km run and I was fine and then did an 8km run on Wednesday but have rested since then. My question is should I be running or resting for the next week? Since Boston is in 8 days and then I have the Big Sur marathon 6 days later. It seems fine once I get going but it’s more after. Is it better for me to rest or maybe go on a couple short runs? Thanks

    • Hi Jenn, thanks for reaching out. Sorry to hear about your injury troubles. You are probably best to just rest for at least a few more days, then maybe run (lightly!) in the 3 days prior to the race, you are unlikely to lose any fitness. You may want to reconsider doing the second marathon though. i know that is not what you will want to hear, but if your pain came back that quickly, it is unlikely to heal completely before the race, and therefore you will probably do more damage during the race. At this point it may be better to pick which is more important to you. We have an article about this here: Hope this helps! Good luck!

  99. Started trying to run in feb this year after no running for 30 years (i’m 48) 4 days before a 5 mile mud run i developed what i believe plantar fashyitis in my left foot. I ran the race breaking the mark I had set for myself. My question is this. Are inserts necessary or should I spend the money for really good fitted running shoes?

  100. Thanks for the article. It was very helpful to me. I have recently been training very hard for an upcoming physical test in about 6 days. The test requires a 300m sprint (under 43 seconds) with a 1.5 mile run (under 9:30) with about 5 minutes in between events. I feel that recently my performance has been declining and I have quickly run to absolute exhaustion in runs that should not effect me in this way. Would you recommend taking a few days off cardio to repair for this test or to push through? Some advice would be greatly appreciated on how long to take off (if you agree) and how to workout in my last few days. I just want to do whatever is best for my performance. Thanks for any help in advance!

    • Hi Jared, thanks for reaching out. We are happy to hear that you enjoyed the article and found it helpful. Hopefully the fitness test went well, and I apologize I was not able to respond before your test. Hopefully you completed the test!

  101. Some people run every day but the majority of people take some time off running every week. What this article failed to mention is the minimum amount of running needed to maintain your running fitness. Everybody is different but I a, sure there are studies out there on this.

  102. I am looking for some input from either coach Tina or Jeff. I am a 37 year old male who has been running for roughly five years. I run year around and average between 40-50 miles a week. My 5k time ranges from mid-18 to 20 minutes and my half time ranges from 1:28 to 1:33. Unfortunately I was diagnosed with pneumonia today and ordered bed rest for the next week. I know pneumonia attacks the lungs, vital organs for the runner. Although I have been prescribed a week of bed rest I am considering one full week off and the second week very easy and light runs. My other consideration is to give the body a full two weeks to heal. Admittedly I am scared. I am nervous of having to start from scratch. I have read your article many times and recognize that there is a very negligible loss of Vo2 capacity and I am still looking for some feedback. Any advise would be greatly appreciated as I have a tendency to push my body to the limits and sometimes beyond.
    Thank you

    • Hi Jason, thanks for reaching out. Sorry to hear about your pneumonia, and rest was probably the best idea for you, especially as you are risking your long term healing. As we stated in this post, you are really not going to lose too much in the few weeks. Hopefully by now you have taken that rest, and you are easing back slowly. This is a time you really need to ensure that you listen to what your body is telling you. It might be a good idea to wear a heart rate monitor on your return, and keep your heart rate in your easy zone. We have a calculator for that (link above) which should help you. What else can we help you with?

  103. hey, ive just started runnin the in the last months. i run about 6k a day 5- 6 days a week.. this week i have pushed it to almost 7 and my legs are slightly sore in places so i took today the 5th day off.. i cant help but feel guilty or like im letting my progress down. but it feels like some days rest could be good for me.. how
    many days a week would you reccomend runnign and resting??

    • Hi Jarrod, thanks for reaching out. It is good that you are listening to your body when you feel tired and resting. This is a good idea, and what you should continue to use as you move forward with your running. Rest days are good for your body to recover and adapt, so we would recommend that you continue doing them. As you have listened to your body this time around with taking that 5th day off, it means you are naturally good at trusting your judgement, it would be best for you if you continued to trust those gut instincts on your days off!

  104. Here’s MY dilemma: I ran a full 3 weeks ago. I was fully trained for it, but 4 days after the race, when I went to go for a little run, my knee was in serious pain and I only made it .31. I did a little bit of cross training the next 2 weeks. I did a 2 mile run this past Sunday (5 days ago) and it was a tiny bit sore, but nothing bad. However, I am signed up for another full NEXT WEEKEND, and I’m fighting myself whether or not I can/should do it, or maybe just do half? Or none? I was SUPPOSED to get a 12 miler in, and an 8 miler this weekend, but of course neither of those happened – or will happen. OR! SHOULD I try to do the 8 miles this weekend to see how my knee is?

    • Hi Nikki, my best recommendation would be to rest up and chose another race in the future. You are putting your long term running at risk, and it could mean you are out for a long time if you do this. At the end of the day, it is your choice, but we would recommend getting your knee taken care of and fully healthy, then looking for another race. Try to get in to see a physical therapist if you can, or let us know what your doctor says your knee pain is so we can suggest how to rehab it. Thanks for reaching out!

  105. I am a competitive long distance runner. I have developed a hip flexor injury back in august this year and it is still on going till today. I have been doing cross training or light jogging for the past 3 months. Does the 3 months of crosstraining/light jogging help to maintain my fitness just before my injury?

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  107. I am so glad I found this article! This is my fourth day missed but now I am safe to run later in the day. According to your reasoning, I have not lost much fitness and am safe to run at the speed and endurance I am used to.
    I hope this is the case! Thanks so much 🙂

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  112. I mad it through 20 weeks of marathon training with zero setbacks. I peaked at 18 miles. However, the last 6 weeks have been a struggle with a nagging knee injury. Rest does seem to help my knee. I haven’t missed any of my weekend long runs but I have missed most of the weekly runs. Last weekend I ran 20 miles and now I’m into my taper. Before my marathon training I had 18 weeks of training for a half marathon. Essentially, from January – October I ran with no issues. However, now as the marathon approaches I’ve been missing weekly workouts. In your experience, am I prepared enough to finish? At this point, I’ve given up on any time goals. As it is my first one, I just want to finish.

    • First and foremost, having you been wearing the same should throughout training? They may be beyond their life causing some of those aches and pains. And of course the miles are catching up. It’s normal to go into taper “beaten up” slightly. From the miles. Now you rest and recover. Sounds like you’ve done plenty of training and mileage. And I wouldn’t be so quick to give up on time goals. Best to take a step back for a few days. Try not to think about the race upcoming. Just enjoy life and I bet in a few days you’ll have a new perspective of the upcoming race. Keep us posted and good luck!

      • I have changed shoes but I think I probably did so a little too late. I’m concerned about missing the runs during the week over the last few weeks. Hoping that taking the time off to get healed won’t hurt me too much. Going into the marathon I will have missed about 4 weeks of weekly runs but none of my weekend long runs. Since this is my first one I’m not sure what to expect from my body on race day. Just worried that too many weekly misses will catch up to me.

        • I think you’ll do better than you think right now. Stay in the new shoes, don’t use the old until after the race if even then. Cut the grass with the old ones! The key runs are the long runs, not the weekly, sometimes called garbage miles (loosely defined). The long runs is the key especially for your first marathon. The marathon is another long run. Respect the distance but don’t fear it. Treat it like another long run. Good luck!

  113. Hi Jeff,

    Thanks for the article! I’m scheduled to run my first marathon in less than 2 weeks. Training has been great and I’ve been feeling amazingly strong, except after my final long run about a week ago I’ve had a dull pain and tightness on the outside of my hip down to the knee. I’ve been foam rolling and icing pretty religiously, but still had pain on an easy run today. Would it be detrimental to my overall fitness to take the remaining time leading up to the marathon off from running? Should I even attempt the marathon? The thought of posting a DNF is heartbreaking after all the training I’ve put in!

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