Sleep Loss and Post-Exercise Muscle Recovery Hormonal, Inflammatory, Metabolic and Circadian Mechanisms with Practical Implications for Athletes

Abstract

Introduction and aim: Sleep is essential for skeletal muscle repair, endocrine regulation, immune balance, metabolic homeostasis and adaptation to exercise. In athletes and physically active individuals, insufficient sleep may impair post-exercise recovery and reduce physical performance. The aim of this review was to analyze the hormonal, inflammatory, metabolic and circadian mechanisms through which sleep deprivation may affect skeletal muscle recovery after exercise. Materials and methods: This narrative review was based on a literature search conducted in PubMed, Scopus, Web of Science and Google Scholar. The analysis included systematic reviews, meta-analyses, randomized and controlled human studies, experimental sleep restriction studies and selected animal or cellular studies that provided relevant mechanistic explanations. Publications concerning sleep deprivation, exercise recovery, skeletal muscle metabolism, hormonal regulation, inflammation, mitochondrial function, circadian rhythm and physical performance were included. Results: Available evidence indicates that sleep deprivation may disturb the GH/IGF-1 axis, increase cortisol activity, alter testosterone secretion, promote inflammatory dysregulation, reduce myofibrillar protein synthesis, impair mitochondrial function, decrease insulin sensitivity and disrupt skeletal muscle circadian regulation. These mechanisms may contribute to impaired muscle repair, reduced recovery capacity and less favorable training adaptation. Conclusions: Sleep should be regarded as an active component of post-exercise recovery rather than a passive period of rest. Sleep optimization, sleep extension before anticipated sleep loss, strategic napping, appropriate training load adjustment and adequate nutrition may support recovery in athletes and physically active individuals. Further studies are needed to clarify dose-response relationships and to identify the most effective recovery strategies in real-world sports settings.