Cookies on this website

We use cookies to ensure that we give you the best experience on our website. If you click 'Accept all cookies' we'll assume that you are happy to receive all cookies and you won't see this message again. If you click 'Reject all non-essential cookies' only necessary cookies providing core functionality such as security, network management, and accessibility will be enabled. Click 'Find out more' for information on how to change your cookie settings.

PURPOSE: We examined iron absorption and its regulation during two common scenarios experienced by endurance athletes. Our aims were to: (i) compare the effects of preexercise versus postexercise iron intake on iron absorption; and (ii) compare the impact of training at altitude (1800 m) on iron absorption preexercise. METHODS: Male runners (n = 18) completed three exercise trials over a 5-wk period, each preceded by 24 h of standardized low-iron diets. First, athletes completed two 60-min treadmill running trials at 65% V̇O2max at near sea-level (580 m). In a randomized order, preexercise and postexercise test meals labeled with 4 mg of 57Fe or 58Fe were consumed 30 min before or 30 min after exercise. Then, the same exercise trial was performed after living and training at altitude (~1800 m) for 7 d, with the labeled test meal consumed 30 min preexercise. We collected venous blood samples preexercise and postexercise for markers of iron status and regulation, and 14 d later to measure erythrocyte isotope incorporation. RESULTS: No differences in fractional iron absorption were evident when test meals were consumed preexercise (7.3% [4.4, 12.1]) or postexercise (6.2% [3.1, 12.5]) (n = 18; P = 0.058). Iron absorption preexercise was greater at altitude (18.4% [10.6, 32.0]) than at near sea-level (n = 17; P < 0.001) and hepcidin concentrations at altitude were lower at rest and 3 h postexercise compared with near sea level (P < 0.001). CONCLUSIONS: In an acute setting, preexercise and postexercise iron absorption is comparable if consumed within 30 min of exercise. Preexercise iron absorption increases 2.6-fold at altitude compared with near sea-level, likely due to the homeostatic response to provide iron for enhanced erythropoiesis and maintain iron stores.

Original publication




Journal article


Med Sci Sports Exerc

Publication Date





118 - 127


Humans, Male, Iron, Running, Exercise, Erythrocytes, Athletes