Iron Deficiency in Runners
Outside of training deficiencies, low iron levels in runners is one of the most common reasons for poor results during workouts and races. Recent research indicates that almost 56% percent of joggers and competitive runners suffer from an iron deficiency that severely hampers performance. By closely monitoring iron intake and supplementing if needed, you can quickly boost performance and prevent lulls in your training.
Symptoms of Iron Deficiency in Runners
Determining if you have an iron deficiency can be somewhat difficult if you’re a runner. The main symptom of low iron levels is fatigue and a slight shortness of breath. You can appreciate the dilemma here if you’re a runner – you’re always tired after a workout and shortness of breath defines our preferred mode of transportation.
If you are worried that you might be iron deficient, you should schedule an appointment with your physician for a blood test. It’s a simple test that most doctors would be willing to provide if you tell them you’re running a lot of miles and feeling more fatigued than usual. Even if you are not iron deficient, you can establish a good baseline for your iron levels, which could help you identify an iron problem down the road.
The major results of interest to runners are: hemoglobin (Hg), hematocrit (Hct), iron (Fe), total iron binding capacity (TIBC), and ferritin. In anemia, your hemoglobin and hematocrit, which are a measure of your red blood cell count, are low. In iron deficiency, your iron is low, your total iron binding capacity is high (meaning there is lots of extra room to bind more iron), and your ferritin (a measure of your iron stores) is low. In my experience coaching elite runners, a ferritin level less than 30 ng/ml in women and less than 40 ng/ml in men is often enough to reduce performance and impact your running.
Why is Iron Important for Runners
Red blood cells, which contain hemoglobin (an iron-containing protein), transport oxygen to your working muscles when you run. If you have low iron levels, you will generate fewer red blood cells and your hemoglobin levels will decline. Therefore, less oxygen will be transported to your muscles, and running performance will suffer.
How Runners Lose Iron
Runners lose more iron than non-runners for a multitude of reasons.
Through your feet – First, a process called foot strike hemolysis occurs in runners, especially those who run high mileage. Foot strike hemolysis is a process where red blood cells are damaged when the foot hits the ground, thus reducing your hemoglobin levels.
Through sweat – Iron is lost through sweating. While the amount of iron loss isn’t staggering, for a runner working out in hot and humid conditions, the losses can easily add up.
Through the intestines – Loss of iron through the GI tract (primarily the stomach or large intestine) is a problem for some athletes. Iron loss through the GI tract is fairly minor, but there may be a cumulative effect over months of running that leads to iron deficiency.
Female runners – Finally, female runners have an especially difficult time maintaining proper iron levels since they also lose iron during menstruation.
How to Supplement
As you can see, the cards are stacked against you as a runner when it comes to maintaining your iron levels. Therefore, it is important that you consciously monitor your iron intake through your diet and with supplements, if you already have low levels.
Iron rich foods
Good food sources of iron include: lean meat, oysters, egg yolk, dark green leafy vegetables, legumes, dried fruit, and whole grain or enriched cereals and bread. If you are worried about your iron levels, avoid drinking coffee, milk, or tea with iron-rich meals, as calcium inhibits iron absorption. In addition, you should drink vitamin C with your iron rich foods since vitamin C aids in absorption.
Supplementation
I suggest most runners be on an iron supplement unless their iron levels have tested high in the past.
- When you go to buy an iron supplement, make sure it’s in the form of ferrous sulfate. Usually, you can find iron at a health store like vitamin world or a GNC. You can take iron in a pill or liquid form, whichever works best for you. Pills are often easier to find, but liquid absorbs better.
- Like when you’re eating, avoid calcium an hour before and an hour after taking your iron. Likewise, take with vitamin B (a pill or orange juice) and a B-complex supplement to aid absorption.
- I suggest taking your supplement before bed. Iron supplements can sometimes cause minor stomach issues and gas. If you take them at night, it probably won’t bother you. If your stomach does bother you, taking ferrous gluconate rather than ferrous sulfate can be easier on your stomach. Iron supplements can also cause constipation, so you could consider a stool softener if needed.
- If you’re just looking to maintain your iron levels, supplement with 30mg of elemental iron. If you are iron deficient, supplement with 60mg of elemental iron.
By paying attention to your iron levels, getting tested if you think you may be low, and increasing your iron intake through diet or supplements, you can avoid lulls in your training and boost performance.
Coach Melanie
is instrumental in helping the coaches at RunnersConnect develop safe and progressive training plans for you. Dr. Schorr was a Division-I All-American runner while at Dartmouth College. After graduation, she attended medical school at Johns Hopkins, where she continued to train and compete in marathons and half marathons. Dr. Schorr is now in her residency program at Harvard’s BWH in Boston and she strives to be a model for those who balance their professional lives with their training and racing goals. Learn more about Coach Melanie and all our 
How about using cast iron cookware – some of the iron is supposed to leach into your foods.
Yes, cast iron cookware will leech iron into your foods. Good suggestion, Stephen. While cast iron cookware won’t provide you with a ton of iron, it can help boost your intake up a little bit, especially for vegan runners who don’t eat red meat. Thanks for the suggestion!
THANK YOU, THANK YOU, THANK YOU for this post!!!!! I’ve been trying to find answers about iron deficiency for awhile. I’ve been tested and had super low iron levels. I took a supplement prescribed by my doctor but it wreaked havoc on my stomach. It’s important so now I know how to make smarter choices. I appreciated this article so much!
I am very happy the article helped you so much, Samantha. If you have any other questions about iron or have trouble finding a good supplement, don’t hesitate to let me know. Happy running!
Hi Melanie this is a great article. What are your thoughts on taking black strap molasses to get your iron? I’ve heard it’s more absorbable than supplements but I don’t know. And are there any potential side effects from taking iron supplements when you don’t need it?
You’re welcome, Daniel.
I’ve never heard of black stap molasses in general. After looking it up, it does appear to be a good source of iron, but it also has a lot of calcium, which hinders absorbtion. It’s certainly a good natural way to increase iron stores, but I don’t know exactly how effective it is.
As for the potetial side effects, taking too much iron can be toxic. The main synptoms would be nausea, vommiting, and major constipation. However, it does take a lot of iron to over supplement and if you stick with the guidelines provided above, you shouldn’t have any issues.
Good luck!
I have been having a huge struggle training for my marathon in June. I just got my ferritin checked, it was an 8. Not one of my long runs have been good, they are a fight to finish. I’ve read so much information and learned so much, but I can’t seem to find anything about weather or not I should continue to train and if it’s realistic to have a good marathon come June.
I am taking an iron supplements, I have surgery in mid May to correct my long and heavy menstrual cycles. I’m a fighter so it’s hard for me to know whether I should continue to push training or not. I know it takes 4 months to completely rebuild iron stores, does that mean that you cannot (should not) run long distance until then?
I would be so grateful for any advise or help. Thank you!
Sorry to hear your training has been such a struggle, Pam. With a ferritin of 8, I don’t recommend you continue to train hard and push for the marathon. You’re correct, it takes about 4 months of heavy and focused supplementation to get the needle moving when it comes to ferritin and hemoglobin levels. Therefore, I think you’ll continue to struggle with the training, which won’t result in you having a performance you will be happy with. In addition, training hard is at odds with building iron stores, so it’s going to take longer for you to make significant gains in your blood profile. In my opinion, it would be better to scale your training back to a maintenance level that will allow you to keep fit, but won’t interfere with iron absorption. While it means you’ll miss your short-term goal, it will allow you to comeback for a great race faster. Best of luck and I hope that helps.
Thank you so much for your response. I appreciate your advice taking time to explain. It will take some time to absorb but, deep inside I know this is the right decision in the long run. I kept thinking I’d turn a corner in how I felt but rest and maintenance will win out. Thank you 100 x over!
Does this information pertain entirely to teens as well or only somewhat ?
Yes, this information pertains to teens as well. If you’re a female teenage runner, it’s important you eat healthy sources of iron to keep your stores up. Many HS and college female athletes suffer from anemia and low iron levels.
Very informative article. I never paid attention to my iron levels. After reading this article I will get a blood test done and start using iron supplements.
I have just read your article and now everything makes sense. For the last six months I have struggle to run distances that where absolutely no problem to me a year ago! At Easter I had routine blood tests that showed that my iron was low. It was actually only mid June before I felt that I could increase my runs and I feel stronger by the day. Thanks for putting some meat on the bones.
Thank you SO much for this awesome article! Sorry, I have so many questions…I just got tested last week and found out I have a ferritin level of 10.7. Given my low level, do you suggest taking more than the 60mg of iron supplement (that was recommended above)? How mg can I take without overdosing on iron? I read online iron injections are one treatment…is this the fastest way to increase ferritin levels? I started taking the supplements in the form of Hydrolyzed Protein Chelate (but with no direction, at <60mg/day) and have already started feeling better. I took a few days off and have started running easy, but is it ok to resume my training and racing schedule despite being iron deficient? Dying to get back on the road here! Any guidance would be greatly appreciated!!
Hi Eva, I am glad you enjoyed the article and had your blood work tested. To answer your iron related questions, I would take two 60mg supplements of ferrous sulfate per day (one in the morning, one at night). You can take it in pill or liquid form (liquid is absorbed easier and should be taken with orange juice to prevent teeth staining). The other forms of iron are not readily absorbed. Iron injections are really only for individuals who are severely anemic (which you are not) and who cannot take an oral supplement.
As for training, I would defer to coach Blake as I think he has a better long-term view of your training and racing plans. He is very experienced working with runners who have iron issues and will make sure your training coincides with getting your levels up.
Hope that helps!
Hi Eva –
I’m glad the article helped and I see that Coach Melanie has already helped with a great response.
As far as training goes, the real question that any runner in your position wants to know is – how long until I feel like myself again… Unfortunately, there is no formula that applies universally. I’ve read that it takes three months to return to normal ferritin and activity levels but with rest and supplementation I think that two weeks is a very realistic expectation. Obviously that’s a wide range but I expect for you to be on the low end of that.
I’m familiar with your circumstances and your training so I’m confident in saying that you can do a workout this week and you’ll be feeling fit and ready in time for your marathon training to start in August.
Talk to you soon!
Blake
Thank you for the article, Coach Melanie!
I never thought to seek so many parameters for iron levels. I am a first-year graduate student getting immunizations for school on Monday, so I will ask if they can perform this blood test for me!
Unfortunately, almost all the high-iron foods you mentioned I do not enjoy. This is with the exception of fortified cereal (I do eat Total Cereal), but I have not considered until now that eating it with milk (calcium) would decrease the iron absorption!
I thought of a few questions:
1) What would be a good substitute for milk that I could use so that the iron could be absorbed readily by Total Cereal? I might have to resort to eating the cereal plain (from a Ziploc bag or something!)
2) I do like to sprinkle Lemon Pepper on my vegetables. Do you think if I sprinkle this onto Spinach and Tomatoes, that it could have the same effect of increased absorption that you said Vitamin B/C can provide?
3) I tend to lean toward “natural” intake of nutrients and vitamins. However, I am still keen to read your advice regarding supplements. What are potential dangers of liquid iron supplements? In your article and comments, you mentioned teeth staining, “stomach problems”, and iron overdose leading to vomiting, constipation, and fatigue. What are the long-term effects of iron overdoes, and what are the chances of iron poisoning? Also, could you elaborate more on what “stomach problems” could occur?
4) I am considering iron supplementation. You suggest supplementation in the form of “ferrous sulfate”. Will this be clearly labeled, and what other forms of supplementation are there (so that I can know to avoid those other forms).
5) Does your suggestion for liquid ferrous sulfate iron supplementation come not only from scientific/physiological knowledge, but also from application? That is, do you personally, or do you personally know other successful runners who, follow this suggestion?
Thanks again!
Hi Lin,
I am glad the article helped so much. Lot’s of tough questions, I’ll do my best:
1. Soy milk and rice milk with have less calcium. However, fortified cereals are not a good choice for iron. For example, iron fortified cereals can contain actual iron filings, which is a far cry from the bioavailable iron you get from iron-rich vegetables like spinach.
2. I am not sure why it would? I don’t have an ingredients label, but does lemon pepper have B-complex or Vitamin C?
3. Stomach problems would be generally upset stomach and constipation. Iron over-dosing is the most common issue, but if you follow the guidelines in the article, that shouldn’t be a problem. Iron-over dosing is something that is far too complex to cover in a comment. I will write an article about it.
4. Yes, it will be clearly labeled on the package or in the ingredients list. the other common forms are iron fumarate or iron chelate.
5. Yes, these guidelines are both from my experience as a physician and from my time spent as an elite runner.
Best of luck!
Thanks so much for this information. My son is a X-country/Track coach and we’ve discovered that quite a few of his runners are quite likely anemic. The one runner who was tested for ferritin serum came back with a count of 4!! It’s a wonder he’s walking around let alone running. I’m a midwife and will be helping parents get the blood work they need to test their own children and then will recommend nutritional sources as well as supplemental iron to build their kids up. One thing that I would recommend that you NOT recommend is ferrous sulfate. It’s very toxic and the cause of digestive upsets and constipation. There are many natural herbal iron tinctures and liquids that are a much better source of easily absorbed iron. Thanks for all the tips on how and when to take it.
Thanks for commenting, Judith and I am glad the article helped you and your son. However, ferrous sulfate is NOT toxic (not sure where you’re getting that info) when taken in the recommended dose. More importantly, it is the most readily absorbed type of iron, which is why it is the number one doctor recommended iron supplement to treat iron deficiency.
Hi,
I am due to run a marathon in 10 days and have just found out that I have a low iron level. Having not taken iron tablets before, is it worth beginning the supplements now as I know it takes 3 months to really increase your iron level properly? I don’t want any side effects to affect my marathon?
Thanks
Hmm, that’s actually a tough question, Charlotte. I think I would do this – take a liquid iron supplement for the next 6-7 days. It should upset your stomach too much and you’re not training hard, so even if it does bother you a bit during a run, it won’t compromise and important workout. Then, about 4 days from the race, stop taking the supplement to allow everything to get back to normal. this should get your iron levels up a bit while leaving your stomach fine for race day. Hope that helps and good luck!
I have a half marathon in 5 days and recently found out (through a blood donation) that my Ferretin level in 10, which explains so problems
What can I do to help myself out?? I really still want to run!!
Sorry to hear about the low levels, Jen. You can still run, just be aware that you might not have your best performance. You can start supplementing right away with the liquid iron and adding more iron-rich foods to your diet. It will take about three weeks to see changes in your blood profile, but the sooner you get started, the quicker you’ll start feeling better.
Hi there,
This article is great and the Q+A at the end is extremely useful. I’ve had low iron in the past and think I’m suffering the same thing again after I really dragged in a marathon last week, coming in 25minutes over my predicted race time for no good reason. I’m waiting on my blood results but expecting a low ferritin. I’m supposed to be running a 40mile race (my first) in 4 months time and training starts now, pretty much. Most weekends I’ll be covering upwards of 26miles over 2days, plus running midweek as well. Is this a really daft idea? I’ve already run two marathons and a half marathon this year but I really don’t want to pull out of the ultra as I’ve told everyone I’m doing it!
Sorry to hear about your iron issues, Kitty. Hopefully, you’ll be able to get your numbers up quickly and glad the info helped.
If you’re training for an Ultra, I would say every other weekend should be a back-to-back long run. That is how I coach for the Ultra. Just make sure your blood work looks good!
Hi. I have a question regarding supplementing with iron. I have run 6 marathons (so I know what the training is like) and am currently in training for another marathon in late June. Two years ago I was found to be “slightly” anemic (hemoglobin level was low) and at that point I was COMPLETELY fatigued all the time with significant hair loss and brittle nails. Per doctor instructions I supplemented with iron for several months and felt much better.
Fast forward to now. I’m feeling fatigued again with more hair loss and brittle nails. I was feeling quite happy that I seemed to have caught it earlier this time and have just had an appointment with the doctor. I got my bloodwork results back and my hemoglobin was in the normal range but my ferritin was 14. This doctor told me NOT to take an iron supplement (we have moved since my anemia 2 years ago and have a new physician now). I have a follow-up appointment with her next week where I will discuss this with her further but I have actually been taking an iron supplement for 3 weeks already (because I felt I knew the symptoms and also knew that it takes quite some time to get back to normal). I had told the doctor that at my appointment and she told me to stop taking them. Considering my poor running performance, fatigue and the fact that she and I are seriously discussing that I get a uterine ablation to control my extremely heavy periods….is there any harm in my continuing to supplement with iron? Just FYI she had my thyroid function checked as well and everything came back normal there.
Again running off past experience from training cycles I cannot pinpoint another reason (I’m sleeping plenty, eating very well, my weight is stable to what it has been for my other training cycles) for my fatigue and poor running and everything I have read indicates that a ferritin level of 14 is too low for an endurance runner.
Thank you for your time.
Hi Jaci,
Sorry you’re having issues. While I agree that 14 ferritin is low and should be supplemented, I would still wait to listen to your doctor and/or get a second opinion. Ferritin guidelines are different for runners and “normal” people, so while 14 might be within normal range, it’s perhaps not what your number should be. I would ask if that us how he/she is basing their decision to not supplement. If so, seek the consultation of a doctor more familiar with runners. However, it’s possible he/she has another reason, based on medical data I don’t know, about the reason for not supplementing. Hope that helps.
Thank you for your reply. I followed up with my doctor and apparently the person who called with my lab results gave me the wrong information when telling me not to supplement. My doctor DOES want me to continue with 325mg ferrous sulfate tablets per day for 3 months and then get bloodwork rechecked. She said a ferritin level of 14 is quite low considering I’d already been supplementing for almost 3 weeks prior to my bloodwork.
Now to get the heavy periods taken care of so hopefully this low iron issue can be resolved for good.
Thankfully I’m starting to feel a bit better AND the weather is finally supposed to take a turn toward spring-like. Hoping that means I can get out and actually enjoy running again.
I have a high school daughter who runs xc and track. How do you balance getting enough calcium and iron? Both being an issue with teen girls who run. I was having her take a calcium supplement with her meals, but now I’m not so sure seeing that the calcium may inhibit the iron absorption.
Great question. Just separate the times you take both supplements. have calcium in the morning and then iron at night. That should be prevent any potential interaction with the two.
Hello,
Thank you so much in advance for your help. I found out that my iron level is not measurable (less than 5), but I am planning to run a 50K May 25th. I was already taking 150 mg Feramax, and my doctor has told me to double up on it. I have been doing that for about a week already. I am trying to eat iron-rich foods, e.g. liver. I am going to start taking the iron at night so my coffee in the morning won’t interfere with absorption. My question is whether you think that will be sufficient to run on race day?
I really appreciate anything you can tell me.
Hard to say since iron levels don’t increase at a predictable rate. However, your numbers probably won’t be in the normal range by race day judging by your currently very low numbers. Does that mean you can’t race? No. But, I would definitely be prepared to slow your pace down and run less for time and more for fun.