The Danger of Low Iron in Runners in the Summer

I’ve seen it time and again, mother runners suffering from low iron. It’s really common among female endurance athletes. In fact, one study found that it impacts about half of them.

The issue is becoming more well-known, thankfully. But a lot of runners are suffering from poor performance, fatigue, and other symptoms due to an iron deficiency–especially in the summer months when we lose iron through sweat. And, these runners are quick to blame temperatures or lack of sleep when the culprit lies inside. 

I was one of them. 

My experience with an iron deficiency

I realized I had low iron soon after becoming more competitive with my running. I finished a track workout in the mid-morning heat and my paces for mile repeats were about a minute off. I could barely jog my two-mile cool-down home.  My coach called right away when he saw my splits on Strava and suggested I get some bloodwork done.

I got a blood test which most doctors will easily perform to illuminate my iron stores number, also known as ferritin. Most running coaches and health professionals agree that a level lower than 30 for women is likely to affect performance. The optimal ferritin range for female endurance runners is 50-100. My level was 14. 

Are women more likely to have low iron?

About one in two female endurance athletes are low in iron. Why? There are four main reasons.

  • For one, premenopausal women lose iron during their periods as blood is rich in iron.
  • They also lose iron every time their feet strike the ground as the pounding destroys red blood cells.
  • Also, sweating depletes your iron as you sweat out the mineral. Therefore, you’re more likely to lose iron in the summer months, studies find.
  • Finally, running can cause a hormone spike post-workout that inhibits iron absorption. Adding insult to injury is your diet. If you’re a vegetarian, plant-based iron is absorbed less by the body than animal-based iron.
signs of iron deficiency in female runners
Pin these tips for fixing low iron for later.

Related: RED-S: Signs & treatment

Can low iron affect your running?

Yes. Being low in iron can be detrimental to the way you feel and how you perform. My coach was shocked that I was able to get out of bed with my low iron because an iron deficiency in runners can lead to extreme fatigue.

Iron is part of the protein hemoglobin which plays a starring role in supplying your muscles and organs with oxygen. Iron is also found in muscles in the form of myoglobin, the protein that extracts oxygen from hemoglobin molecules. There must be enough iron for the metabolism and transport of oxygen to function properly–particularly during exercise. Iron also works to convert carbs and fat into energy.

So, if you’re low in iron, you’re likely feeling low in energy.

Here are signs of iron deficiency:

  • Not recovering well after runs
  • Frequent injury
  • Frequent illness
  • Tired all the time
  • Irritable
  • High exercise heart rate
  • Fatigue early on in a workout

Related: Hidden health benefits of running

So how can you fix low iron? Here are 6 ways to increase your iron levels.

6 Ways to Fix Low Iron in Runners

signs of low iron in runners
Pin these tips to fix your low iron for later.

Eat iron right foods.

Eat iron-rich foods like beef, eggs, chickpeas, and dark chocolate. Reminder, iron from animal-based products have a higher rate of absorption than those from plants. 

Take an iron supplement.

I take MegaFood’s Blood Builder which has been a gamechanger and moved my numbers better than any other supplement. It’s all-natural, can be taken on an empty stomach, has vitamin C to help with absorption, and also B12 and folic acid which women tend to be low in any way. Also, you can double up on the supplement if your levels are low enough (and your doctor says it is okay). I take two per day if I am running a lot in the summer.

Pair Vitamin C with iron.

Speaking of vitamin C, I aim follow any iron intake with vitamin C like by drinking a glass of orange juice. Moisture-rich foods like applesauce or spaghetti sauce can also aid in intake. Bonus points if you drink a smoothie that has OJ in it.

Avoid taking iron with caffeine, calcium, and zinc.

Do not take your iron supplement with caffeine, calcium, and zinc which can interfere with absorption. Thus, I do not take my supplement in the morning with my coffee. I wait until several hours later.

Cook with cast iron skillets.

I use my Le Creuset cast-iron skillet as much as I can which can add iron to the food you cook. 


Planned breaks after a training block are beneficial to your mental and physical health in so many ways, including allowing your iron levels to regulate. Aim to take at least a week or two off in between training cycles. 

Related: Why You Need to Take a Planned Break

It can take about a month of these measures before you notice an improvement. But, it is kind of amazing. Simply by ingesting more iron, you will notice more energy and better running performance. 

We would love to help you with your running goals. Check out our coaching services for mother runners.

2 thoughts on “The Danger of Low Iron in Runners in the Summer”

  1. Oh my gosh thank you for this iron information. I have been back into running for a few years. My dr tested my iron among other things at a physical 2 years ago and my iron level was a 7. I had a colonoscopy, endoscopy and other tests to try to figure out why it was so low. They still don’t know after 2 years. This could help explain it too! I’ve been taking supplements and luckily they’re enough where I don’t need an IV bag of iron every so often. I was SO tired! It’s amazing how the body works. Thank you for this information!!

    • Hey Katie! Thanks for reading & sharing. I am so sorry about your iron issues! Is it back up again? I still take a supplement even though my levels have been normal. Did you happen to get your gut checked to make sure all the bacteria are balanced?


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