Beyond the HPG Axis in Relative Energy Deficiency in Sport: Sleep, Psychological Health, and Neuroendocrine Adaptation in Athletes — A Structured Narrative Review
DOI:
https://doi.org/10.12775/QS.2026.57.72608Keywords
Relative Energy Deficiency in Sport, REDs, low energy availability, sleep, mental health, neuroendocrine adaptation, athletes, Female Athlete TriadAbstract
Background: Relative Energy Deficiency in Sport (REDs) is increasingly viewed as a multisystem condition related to problematic low energy availability (LEA), but evidence beyond reproductive and skeletal outcomes is uneven.
Objective: To synthesize evidence on sleep, psychological health and neuroendocrine adaptation in athletes with LEA/REDs, while distinguishing established mechanisms from emerging domains.
Methods: A structured narrative review with evidence mapping was conducted in PubMed/MEDLINE; 61 full-text records were assessed and synthesized across predefined domains.
Findings: The strongest support concerns endocrine and metabolic adaptation, including thyroid, adipokine, somatotropic and stress-axis pathways, although individual markers remain non-specific. Sleep and psychological outcomes are clinically relevant but rely mainly on heterogeneous, mostly observational evidence. Direct neurocognitive evidence in athletes with well-characterized LEA/REDs remains insufficient.
Conclusions: REDs should be considered beyond an HPG-centered framework, but claims regarding sleep, psychological health and neurocognition require caution. Future studies should combine objective LEA characterization, longitudinal designs, endocrine profiling, sleep assessment and direct cognitive testing.
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Copyright (c) 2026 Mateusz Polak, Jakub Grandos, Beata Huszcza, Agnieszka Olejnik, Konrad Gronek, Julia Kaczmarek, Dominik Gajewski, Zuzanna Głowacka, Kinga Kościołek, Mateusz Kosowski
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