Iron deficiency in athletes: why endurance athletes are most at risk

Iron deficiency is one of the most commonly missed causes of fatigue and declining performance in athletes. Endurance athletes, women and young athletes are most at risk, because they lose more iron and often take in less. The earliest clue is in your ferritin, often before your haemoglobin drops.

Many people only think about iron once they are already wrecked. By then the simplest clue is months old.

Why are athletes at risk of iron deficiency?

Sport raises both your iron loss and your iron need. You lose iron through sweat, footstrike impact while running and small bleeds in the gut, while training demands new red blood cells. Mild inflammation from exertion also blunts iron absorption (Peeling, 2008).

In female athletes, menstrual blood loss adds to that. As a result low iron in this group is more the rule than the exception (DellaValle, 2013).

What are the symptoms of iron deficiency?

The symptoms are vague and resemble ordinary tiredness, which delays the diagnosis. Think of unusual fatigue, breathlessness on exertion, cold hands and feet, and recovery that keeps taking longer. Your pace drops without your training having changed.

Because iron is needed for oxygen transport, a deficiency hits your endurance directly (Sim, 2019).

Which blood values should you test?

Ferritin is the key marker, because it reflects your iron stores and falls first. Haemoglobin only drops later, so a normal blood count does not rule out a deficiency. A combination gives the most to hold on to.

Note: inflammation can raise ferritin artificially. So test at rest and, if needed, alongside CRP to spot any distortion (Peeling, 2008).

How do you address low iron?

Start with food and leave supplementation to a professional, because too much iron is not harmless. Iron-rich food such as red meat, legumes and green vegetables helps, and vitamin C improves absorption. Supplementation can be useful, but only guided by your values and your doctor (DellaValle, 2013).

To track your iron status on purpose, compose a panel through our custom blood test. See also the overview blood values for endurance athletes and tired despite training.

My advice: do not wait until you collapse. A falling ferritin shows months before the wall, and you best discuss supplementation with your GP.

References

1. Sim M, Garvican-Lewis LA, Cox GR, et al. Iron considerations for the athlete: a narrative review. European Journal of Applied Physiology. 2019. PMID: 31055680.
2. DellaValle DM. Iron supplementation for female athletes: effects on iron status and performance outcomes. Current Sports Medicine Reports. 2013. PMID: 23851410.
3. Peeling P, Dawson B, Goodman C, et al. Athletic induced iron deficiency: new insights into the role of inflammation, cytokines and hormones. European Journal of Applied Physiology. 2008. PMID: 18365240.

Disclaimer

Every blood test result includes a professional assessment by a BIG-registered doctor. This article gives general information and is not a substitute for medical advice. A blood test is a tool to walk into the conversation with your GP better informed, not a diagnosis in itself. For treatment decisions, discuss your results with your GP.