Effects of Exercise on Iron Transfer in the Body

Ryuunosuke Takahashi¹ and Takako Fuji¹

1. Department of Sports and Medical Science, Graduate School of Medical Science, Koshukui National University, Tokyo, Japan.

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PUBLISHED: June 30 2025

CITATION: TAKAHASHI, Ryunosuke; FUJII, Takako. Effects of Exercise on Iron Transfer in the Body. Medical Research Archives, [S.l.], v. 13, n. 6, june 2025. ISSN 2375-1924. Available at: <https://esmed.org/MRA/mra/article/view/6673>.

COPYRIGHT: © 2025 European Society of Medicine. This is an   open-access    article distributed    under the terms of the Creative Commons Attribution License, which    permits    unrestricted    use, distribution, and reproduction in any medium, provided the original author and source are credited.

DOI: https://doi.org/10.18103/mra.v13i6.6673

ISSN 2375-1924

Abstract

Although iron is found in trace amounts in the body, it plays an important role in oxygen transport and energy metabolism. Iron is therefore very important for athletes with high oxygen requirements, especially endurance athletes. Despite its importance, many athletes are diagnosed with iron deficiency. The relationship between iron regulation and exercise has been investigated, and it has been suggested that appropriate iron supplementation can improve performance. This review aims to summarize the current understanding of iron transfer in the body, particularly in relation to exercise and dietary intake.

Keywords

• Iron transfer
• Exercise
• Endurance athletes
• Iron deficiency
• Dietary intake

Introduction

Iron deficiency is one of the most common nutritional problems worldwide. It is defined as insufficient iron reaching the body’s stores or various functions. Biological iron metabolism is a semi-closed circuit whose basic functions are the absorption, storage, and reuse of iron. However, depending on the imbalance between iron intake, storage and requirements, deficiencies can develop either rapidly or very slowly. This may be due to inadequate iron intake, certain diseases or, in women, menstrual bleeding. The rate at which iron deficiency develops in individual tissues and intracellular organelles also depends on iron recycling within cells and the hepcidin response.

Iron plays a key role in many biological functions, including mitochondrial function, energy metabolism, and oxygen transport. It is essential for hemoglobin synthesis, which is crucial for oxygen delivery to tissues. Iron deficiency can lead to anemia, resulting in decreased endurance, increased risk of injury, and decreased glycogen stores. Low energy availability (LEA) is commonly observed during high training in endurance athletes and can exacerbate iron deficiency.

IRON AND NUTRITION

Iron is an essential mineral that plays a critical role in various physiological processes. The recommended dietary allowance (RDA) for iron varies by age, sex, and physiological status. Athletes, particularly endurance athletes, may require higher amounts of iron due to increased losses through sweat, urine, and gastrointestinal bleeding. It is important for athletes to monitor their iron status and consider dietary sources of iron, such as red meat, poultry, fish, lentils, and fortified cereals.

INFLUENCE OF EXERCISE AND DIET TIMING ON IRON STATUS IN THE BODY

Fuji et al. investigated how diet timing affects the impact of resistance exercise on improving iron nutritional status in iron-deficient rats. Rats were subjected to resistance exercise and maintained for 3 weeks in two groups: one group received a meal immediately after exercise; the other received a meal 4 hours after exercise. The results showed an immediate increase in iron absorption after exercise, with no increase due to the delayed meal. Both plasma iron levels and body iron stores were significantly higher in the group that received the meal immediately after exercise.

Conclusion

While the physiological mechanisms promoting iron absorption after exercise remain unclear, this study suggests that appropriate dietary strategies may be an important factor for optimizing iron status in athletes. Further research is needed to clarify the relationship between exercise, iron metabolism, and performance.

Acknowledgements

The authors contributed equally to this work.

Disclosure statement

No potential conflicts of interest were disclosed.

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