Relative Energy Deficiency in Sport (RED-S): Gender-Based Impacts on Athlete Health and Performance: A Critical Narrative Review
Samarpita Senapati *
Department of Physiotherapy, Teerthanker Mahaveer University, Moradabad -244001, India.
*Author to whom correspondence should be addressed.
Abstract
Relative Energy Deficiency in Sport (RED-S) describes a constellation of physiological and psychological impairments that arise when athletes do not consume enough dietary energy to support the combined demands of exercise, growth and everyday physiological function. The condition was first articulated as a broadening of the Female Athlete Triad, yet it is now understood to affect male athletes through related, though not identical, pathways. This critical narrative review synthesises contemporary evidence on how the manifestations, detection and consequences of RED-S differ between women and men who compete in sport. The review traces the shared metabolic origins of low energy availability before examining sex-specific divergence in reproductive, skeletal, psychological and performance outcomes. Female athletes more often present with menstrual dysfunction and accelerated bone loss linked to oestrogen suppression, while male athletes tend to present with subtler reductions in testosterone, libido and bone accrual that are easily mistaken for normal training adaptation. Eating disorders and disordered eating remain more prevalent and more readily recognised among women, although under-detection in men appears to reflect stigma and screening gaps rather than true biological immunity. Screening instruments, clinical assessment frameworks and prevention guidance have historically been developed for and validated in women, leaving male-specific tools comparatively immature. The review also engages critically with unresolved debates, including the continuing tension between the Triad and RED-S models, the disproportionate evidence base favouring female physiology, and methodological confounds introduced by inconsistent reporting of menstrual status and hormonal contraceptive use. The review concludes that a genuinely sex-aware approach to RED-S, rather than a female-derived model retrofitted to men, is required to protect the health and performance of all athletes.
Keywords: Relative energy deficiency in sport, low energy availability, female athlete triad, male athlete triad, sex differences, bone health, disordered eating, athletic performance