If you’re training consistently but still feeling sluggish, short of breath, or like your legs just can’t keep up — it could be your iron levels, not your fitness, that are holding you back.
Iron is one of the most important minerals for runners. It helps your body carry and use oxygen, giving your muscles the fuel they need to keep going. Without enough iron, your body tires faster and recovers slower — even if your training plan is perfect.
How Iron Powers Your Runs
When you breathe, oxygen enters your lungs and gets passed into your blood. But oxygen doesn’t move on its own — it needs a ride. That’s where iron comes in.
Iron is a key part of two important proteins:
• Haemoglobin, found in red blood cells, acts like a delivery van. It picks up oxygen in your lungs and drops it off at your muscles.
• Myoglobin, found in muscle cells, is like a storage tank. It holds onto oxygen so your muscles can use it immediately during exercise.
Without enough iron, your body struggles to get oxygen to your muscles — and that’s when fatigue, dizziness, and slower performance set in (Hinton, 2014).
Why Runners Lose More Iron Than Most
Running increases, your body’s iron needs, and at the same time, it increases how much iron you lose.
Here’s how:
• Sweating: You lose small amounts of iron through sweat.
• Foot-strike haemolysis: Repeated impact from your feet hitting the ground can damage red blood cells.
• Intestinal bleeding: Intense exercise can cause tiny bleeds in the digestive tract — especially if you’re running long distances.
• Menstruation: Women naturally lose iron through their menstrual cycle.
• Low-iron diets: Not eating enough iron-rich foods — like red meat, beans, or spinach — makes it harder to keep up.
This makes iron deficiency one of the most common nutrient gaps in endurance athletes — especially in women. One study found that 20–50% of female runners have low iron stores without even realising it (Deldicque & Francaux, 2015).
What Does Low Iron Feel Like?
Low iron doesn’t always show up in blood tests right away. Many athletes are in a state called “non-anaemic iron deficiency” — where they feel the effects of low iron before it meets the clinical definition of anaemia.
Symptoms to look out for include:
• Constant fatigue or heavy legs
• Feeling breathless during runs
• Brain fog or lack of focus
• Slower race times, even with training
• More frequent illness or infections
A 2019 scientific review showed that even mild iron deficiency can hurt endurance, recovery, and mood (Sim et al., 2019).
How Food Can Help (and What Might Block Iron)
There are two types of iron in food:
• Heme iron: Found in meat and absorbed easily by the body.
• Non-heme iron: Found in plants (like spinach or lentils) and absorbed less easily.
For plant-based athletes, pairing iron-rich foods with vitamin C (like oranges or peppers) can help boost absorption. But watch out for tea, coffee, and dairy, which can block it.
A study by Burke et al. (n.d.) found that distance runners who added lean beef to their diets improved their iron levels and body composition — helping them run stronger.
When to Test Iron — And What to Look For
At Epicentre, our Runner’s Performance & Recovery Blood Test Panel includes iron markers that help you see the full picture:
• Ferritin (your iron storage)
• Serum iron (how much is in your blood now)
• Transferrin saturation (how much iron your body is ready to use)
Most doctors only check haemoglobin, but runners need to see all four to truly understand their iron status.
Research shows that runners may need ferritin levels above 30 µg/L to maintain peak performance — even if this level is considered “normal” by general health standards (Sim et al., 2019).
Take Control: Get Tested, Eat Smart, Run Better
You don’t need a referral to check your iron levels. Just walk into any Epicentre branch and ask for the Runner’s Performance panel.
Whether you’re a seasoned marathoner or a weekend 10K warrior, understanding your iron status can help you:
• Boost your energy
• Improve your endurance
• Prevent injury
• Recover faster
📚 References
Burke, D. E., Johnson, J. V., Vukovich, M. D., & Kattelmann, K. K. (n.d.). Effects of lean beef supplementation on iron status, body composition and performance of collegiate distance runners. South Dakota State University. https://openprairie.sdstate.edu/cgi/viewcontent.cgi?article=6884&context=etd
Deldicque, L., & Francaux, M. (2015). Recommendations for healthy nutrition in female endurance runners: An update. Frontiers in Nutrition, 2, Article 17. https://doi.org/10.3389/fnut.2015.00017
Hinton, P. S. (2014). Iron and the endurance athlete. Applied Physiology, Nutrition, and Metabolism, 39(9), 1012–1018. https://www.fortifiedricebybrowns.com/research-articles/iron/iron-and-the-endurance-athlete
Latunde-Dada, G. O. (2013). Iron metabolism in athletes—Achieving a gold standard. European Journal of Haematology, 90(1), 10–15. https://doi.org/10.1111/ejh.12026
Sim, M., Garvican-Lewis, L. A., Cox, G. R., Govus, A., McKay, A. K. A., Stellingwerff, T., & Peeling, P. (2019). Iron considerations for the athlete: A narrative review. European Journal of Applied Physiology, 119, 1463–1478. https://doi.org/10.1007/s00421-019-04157-y
Meet The Author
Loryn Smith is a compassionate Research Assistant at Epicentre Health Research with a Master’s degree in Psychology focused on research methodology and community health.
She has a passion for supporting disadvantaged populations and addressing social inequalities. Loryn combines her research expertise with hands-on fieldwork coordination to help improve health outcomes and empower communities.
