Jeff Gaudette

Written by Jeff Gaudette


Are you Putting Your Body in Danger by Running While Sick?

Sneezing, coughing, congestion, and achy muscles. No, you did not stumble onto a Nyquil commercial. Unfortunately, hard training increases your susceptibility to getting sick, especially if you have children at home.

When you are in the middle of a big training segment, it’s important to know what to do when those symptoms do arise, and you are faced with the question of whether to run or not. To make the decision easy, this article will give you a clear idea of what to run through, and when to rest up.

The most important thing to remember about running when sick is that you should always err on the side of caution if given the choice.

You are not going to ruin your fitness by pushing your workout back a day, or even by taking a few days completely off from running. Yes, runners are obsessive creatures, but two or three days off will not negatively impact your fitness. We looked into this in great detail for our post on How Long Does it Take to Lose your Running Fitness post. Be smart and be patient, and your body will thank you in the long run, pun intended 🙂

Helpful article on when you are safe to run when sick and what symptoms indicate a need to take a day off. Learn how to return to training after sickness.

Running when Congested

If your symptoms are congestion related – runny nose, chest congestion or coughing – you are usually safe to run.

In fact, an easy run, followed by a nice hot shower may help clear your congestion, and give you a few hours of feeling back to normal.

How to adjust your training

Reduce the speed or intensity of your workouts, or  ideally, replace a hard run with an easy day. Being congested and stuffy will make it harder to perform to breathe in and out of your nose, which will limit your ability to run your best.

Instead of setting yourself up for disappointment, have the courage to move your workout backwards. In the words of 2014 US Marathon Champion, Esther Erb, “it takes more confidence to run slowly than it does to run fast.”

If you still plan to workout, start your intervals or tempo run 10-15 seconds per mile slower than you initially intended. If you feel good as the workout progresses, pick up the pace and finish strong. If the workout is harder than expected, keep the paces as you adjusted, and perform the best you can on the day.

Remember, your goal workout paces are merely an estimation of the effort it will take to run that time given your current fitness. So, if you’re congested, you’ll still benefit from the workout, even if it is slightly slower based on conditions.

Running with the Flu

If you have flu like symptoms, especially achy muscles or a fever, you should not run. Running with a fever is not only dangerous, but will significantly increase the time it will take you to get back to 100%.

A fever, by definition, is a rise in the body’s internal temperature in response to bacterial or viral infections. Running also increases your internal temperature, which will make your fever symptoms even worse and could result in dangerous and long-term health consequences.

Likewise, running compromises the immune system, particularly in the first 20 hours after strenuous exercise. Therefore, your body will be more susceptible to the bacteria and viruses already making you unwell, which increases the likelihood of your symptoms taking a turn for the worse.

Furthermore, running siphons away critical energy, nutrients, and resources that could be used to help fight the virus, thereby lengthening the amount of time it takes you to return to full health.

How to adjust your training

You should not run if you have the flu or a fever. Take as many days as you need to feel back to normal with your everyday activities. Remember, it takes at least 10 days to lose significant running fitness, so don’t be worried that a few days off to get healthy will ruin your training.

You should start running again the day after you are able to return to normal day-to-day activities. For example, if you first get sick on Monday, and start feeling normal on Thursday, you should begin running again on Friday. Here is a more detailed look at how you can return to training after getting sick.

Do not try to “make up” missed training in the few days after you return to to running. Your immune system likely still fragile, and your body probably isn’t ready for maximum effort. Spend the first two days running easy mileage with a few strides at the end to snap the legs back into gear. After 2-3 days of easy running, you can attempt a workout.

Be Patient when Sick

No one wants to get sick and lose training time. However, by listening to your body, and being patient in your approach, you can avoid the flu setting you back for weeks instead of days. You will be back to normal training before you know it. Likewise, setting realistic expectations when suffering from a cold or other illness will enable you to adapt and keep your training progressing smoothly.

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30 Responses on “Are you Putting Your Body in Danger by Running While Sick?

  1. Pingback: Running while sick… « Life's Run

  2. My only question is what about taper deadlines?

    While I wouldn’t run a final pre-marathon long run with the flu, would it be alright with a cold? More specifically, is it worse to punt the final long run, and have a two week taper, or to run 20-miles with a cold, but have a three-week taper?

    • Hi Juliet, that is a great question. I think the exact answer would depend on your training. If you’ve had a long build-up; specifically, you’ve had 3-4 really solid long runs, I would skip the long run all together and just focus on resting. This is more insurance that you won’t get any sicker and linger into race day. If your build-up has been shorter and the cold isn’t too bad (meaning you feel 85% or better) go ahead and run easy, but really focus on getting your sleep and fluids the rest of the week. Hope that helps.

  3. Pingback: (Cough) Drop Some Knowledge | chocolate milk and cherry juice

  4. Really? Running is OK with mild productive chest congestion? I hope your right but your the only one saying this. Everywhere else it’s the above the head rule. Any more thoughts on this?

    • As long as you stick to our suggestion of only easy running during that time, you will be okay. If you take it easy, and push your hard workouts back until the congestion has gone, you should not prolong your sickness any further. Everyone is different though, if your gut feeling is telling you to rest, then you are best to listen. Hopefully you never have to come across that situation anyway….we can only hope 🙂

  5. I have a low grade fever, sinus congestion, runny nose and a half marathon tomorrow. I’m on the fence as to whether I should run. I just picked up my race packet but can’t imagine the extra effort it will take to finish strong since I’m feeling crappy. Any advice?

    • Hi Janee, it really is up to you if you want to race or not. You could follow our guidelines about running hard, that would probably be your best bet. Your body would probably appreciate just resting, as there will always be other races, but if you really want to race, then just take it a little easy. Hope you feel better!

  6. I had flu like symptoms yesterday: achy muscles, fever, and just generally feeling really crappy and weak. I convinced myself to do the workout (I’m a high school track runner btw) and it ended up being one of our more intense ones- 4 1000’s at 3:20 pace. Anyways, I’m always one of the first to finish on or faster than the pace our coach sets, but this time I was 30 or so seconds behind and I could barely finish. I skipped the cool down And went straight home. I felt ten times worst than I initially did before the workout- super weak, lightheaded, and an even higher fever and chills. I feel pretty dumb about running after reading this article. We have our second most important meet and one of our most competitive on Thursday and I’m supposed to be running three events: 4×800, 800, and 4×400 and I/we usually at least place in all three. Any advice? Is 2 and 1/2 days of rest in best case scenario enough to fully recover?

  7. Hello,

    I am training for Boston and was supposed to do 21 miles today. Woke up with diarrhea and a slight fever. Went for he run anyways but called it quits at 6.11. I was too tired and felt horrible. It was also snowing and I was getting the chills from being wet with a fever. I also couldn’t fuel properly.
    My question is should I make up the run on Tuesday or Wednesday this week? It would still give me about 17-18 day taper? I haven’t missed any long runs up until now. Last week though was a dial back week. I’ve done a 19, 18, 17 and 2 16s though before that. Training plan has been about 20 weeks.
    Any guidance would be great!
    Thank you,

    • Hi Jenn, sounds like you did the right thing. Your best bet would be to just do a shorter long run if you are going to do it on tuesday or wednesday. It would be cutting it a little close. However, as you have done other long runs like you mentioned, you are probably safe enough to just do another 19-20 depending on how you feel. You are not going to lose anything by missing this one run, even if you do not make up the run at all. Make sure you are getting enough fuel in over the next few days, or you will put your body at risk of burning out and overtraining. Hope this helps. You may find this post puts your mind at ease a little 🙂 Feel better, and good luck!

  8. I am so gutted! I have been training for a half marathon on Sunday and I have come down with a virus. I ache, have swollen glands, sore throat and a temperature. If I feel better by Sunday am I able to run? Or do you have to wait a specific amount of time post virus?? Louise x

  9. I will be running 50km on Saturday and I am having a flu that has started on Tuesday, I wen to Pharmacist and he gave be Flu pack, taking 1 tablet plus 2 capsules three times a day. He told me by Thursday I will be 100% okay.

    Will I be able to make it for ultra marathon on Saturday?

    • Hi Eric, thanks fore reaching out. It would be impossible for us to tell you, your best bet is to truly listen to your heart, as you will know what the right decision is based on how you are feeling. Be very conservative for the majority of the race if you do to make sure you are okay. Good luck!

  10. Hi, question. I came down with a pretty bad flu bug on Sunday and was in bed the whole day. I am not 100% yet but feeling better. I missed my 10 mile long run on Sunday because of it. I’m training for a half marathon and have one more long run of 11 miles this weekend. Should I skip the shorter runs this week and squeeze in the 10 mile run or just forget about it all together?

    • Hi Jason, just forget about last weeks long run, but maybe go for 10-11 this weekend. It is not worth pushing it now, better to get there slightly less fit, but make it to the start line, than not at all 🙂 Make sure you are resting up!

  11. I just learned this lesson the hard way. I had been training 18 weeks to PR my half marathon time and came down with a head cold a couple of days before the half, but I decided I’d take decongestants (which I don’t usually take) and still try (with 80% humidity on race day). I got to mile 11 struggling basically the whole race and suddenly felt like I was going to pass out. I managed to collect myself and zombie walk the last 2 miles and when the finish was in sight I felt like I’d either collapse on the course or walk off and ask someone for help. I did the latter and didn’t finish: If I would have run it easy (for fun) I probably would have been ok.

    • Hi Heather, sorry to hear you had a rough experience in your goal race. There will always be other races, and the hard work you have already put in will still be there, just means next time you have the opportunity, you will have an extra strength! What would you have changed if you could have gone back?

  12. Hi Coach

    i have a sports conditioning course coming on Saturday. i have a cold ie runny nose, and a slight cough but nothing heavy. Part of my course revolves around SAQ so there will be quick movements, jumping and so on, so no marathon like runs etc.

    would i be able to get into this by resting for the this week?

    • Hi Isgak, you are best off resting for a few days, and then doing some light work towards the end of the week. The type of exercises you will be doing should be fine with your symptoms.

  13. Great article. I had taken 3 days off because my knee was bothering me and then I came down with a fever, aches, coughing…..ugh. So now it has been 5 days since a run and I was supposed to run 10 or 11 miles today. (training for a half marathon in three weeks. It is frustrating but I have decided to just not run for a few more days and try for an easy run later this week and then go for a long run next weekend. Does this make sense?

  14. I am supposed to run my final long run of my marathon training tomorrow (20 miles). I have had a cold for about 4 days. If I do not feel up to the run tomorrow should I replace my first weekend taper in with this missed long run? I am just nervous about missing my final long run.

  15. Pingback: Running when sick…Do or Don’t? – run with me

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