Abstract
<jats:p>BackgroundRegular menstrual cycles are an important indicator of health in adolescent and young adult females. Pubertal maturation of the hypothalamic–pituitary–ovarian axis is a sensitive process that may be disrupted by intensive physical activity, particularly when energy intake is insufficient. Female athletes exhibit a higher prevalence of menstrual disturbances, which may adversely affect bone, metabolic, and reproductive health. AimThis review aims to summarize current evidence on the association between intensive physical activity and menstrual cycle disturbances in adolescent and young adult females, with particular focus on prevalence, underlying mechanisms, and health consequences, including the Female Athlete Triad and Relative Energy Deficiency in Sport (RED-S). Materials and MethodsA narrative review of peer-reviewed literature, including clinical studies, meta-analyses, and guidelines, was conducted. Research addressing menstrual function, energy availability, bone health, and endocrine adaptations in young female athletes was analyzed. ResultsMenstrual disturbances occur more frequently in athletes, especially in endurance, aesthetic, and weight-class sports. Low energy availability emerged as the primary etiological factor, leading to suppression of reproductive hormones and menstrual dysfunction. These disturbances are associated with reduced bone mineral density, increased stress fracture risk, and metabolic consequences. The RED-S model expands the Triad by addressing multisystem effects and a broader athletic population. ConclusionsIntensive training combined with inadequate energy intake significantly increases the risk of menstrual disturbances in young female athletes. Early detection, education, and multidisciplinary management focusing on nutrition and training load optimization are essential to protect long-term health.</jats:p>