Athletes and Iron

Why Do Athletes Need Iron?

Adequate levels of iron in the blood are critical for athletes because of the role iron plays in binding oxygen, which must circulate throughout the lungs and muscles in the body.  Vigorous training stimulates an increase in the number of red blood cells and small blood vessels, increasing the physiological demand for iron.  As muscle mass grows, there is a corresponding increase in red blood cells and blood vessels, thereby increasing iron intake needs.[1]

Blood, Sweat & Tears

Athletes are at risk of iron depletion for several reasons. Initially, iron is lost through sweat.  The more an athlete sweats, the greater the risk of iron loss. Iron can also be lost through blood loss.  Strenuous exercise can affect the stomach and intestinal lining, causing gastrointestinal bleeding.  The habitual use of anti-inflammatory drugs by athletes throughout training can also cause gastrointestinal bleeding. Exercise-induced hematuria (blood in the urine) is also a concern after strenuous exercise.

Mechanical trauma, such as foot strike hemolysis, which is the repeated pounding of the feet on hard surfaces, can destroy red blood cells during activities such as running.  Athletes also experience blood loss due to injury, bloody nose, or even menstruation.  Additionally, endurance training can cause rhabdomyolysis, which further depeletes iron stores.


Meanwhile, iron intake through diet is often sub-optimal, due to food regimen during training.  Consuming enough of the right nutrients is rarely enough to meet the recommended daily allowance for iron. Demanding training schedules regularly prevent athletes from consuming regular meals.

Many athletes increase their carbohydrate intake prior to a race, unintentionally reducing their meat intake, further impacting iron levels. Coupled with a reliance on snack and convenience foods (even if they are healthy ones), athletes may not consume enough of the right nutrients to meet the recommended daily allowance for iron. Vegetarian and vegan athletes are at even greater risk for iron deficiency, particularly if they don’t substitute with sources rich in heme iron, the most readily absorbed form of iron.[2]


  1. Mairbäurl, Heimo. “Red blood cells in sports: effects of exercise and training on oxygen supply by red blood cells.” Frontiers in physiology vol. 4 332. 12 Nov. 2013, doi:10.3389/fphys.2013.00332
  2. Uzel, C, Conrad, ME. Absorption of heme iron. Seminars in Hematology. 1998;35(1):27-34.


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