Iron plays a crucial role in oxygen transport and energy production processes, making it an especially important micronutrient for endurance athletes. Iron deficiency, both overt (iron-deficiency anemia) and latent (low ferritin levels with normal hemoglobin), can lead to impaired physical performance, decreased maximal oxygen uptake (VO2 max), fatigue, and prolonged recovery time. Athletes—especially women, long-distance runners, and those undergoing intense training are particularly vulnerable to iron deficiency due to increased losses (e.g., via sweat, gastrointestinal microbleeds, menstruation) and insufficient dietary intake. This paper is a review of the latest journals and scientific articles and discusses the mechanisms by which iron deficiency affects athletic performance, diagnostic methods, as well as prevention and treatment strategies. The importance of individualized ap proaches and monitoring of iron levels is emphasized in the context of optimizing athletic performance and health.