CIRCADIAN RHYTHM AND SLEEP DISORDERS IN ATHLETES: RISK OF INJURY AND PHYSICAL PERFORMANCE - A REVIEW OF CONTEMPORARY DATA

Background. Disrupted circadian timing and poor-quality sleep are common in elite sport and are linked to impaired recovery, reduced performance and a higher incidence of injury. Aim. To synthesise contemporary evidence on how specific sleep and circadian disorders affect physical performance and injury risk in athletes. Materials and methods. Narrative review of English-language studies published 1997–2024 identified through PubMed and Scopus using the terms athlete, sleep disorder, circadian, performance and injury; 109 articles met the inclusion criteria. Results. Pre-competition insomnia, delayed sleep-phase disorder, jet-lag–related disturbance and chronic sleep restriction collectively affect 30 to 70 % of athletes, with prevalence highest during congested travel and training periods. Sleep loss ≥ 2 h night⁻¹ or efficiency < 80 % reduces VO₂max, sprint speed and strength by 3–10 %, slows reaction time, elevates cortisol and inflammatory cytokines, and doubles musculoskeletal-injury risk. Chronotype misalignment further impairs performance when competition occurs at non-optimal times of day. Conclusions. Sleep and circadian disorders are widespread in competitive sport and materially degrade both performance and tissue resilience. Systematic screening, chronotype-aligned scheduling, travel-fatigue management, sleep-extension strategies and judicious melatonin use should be embedded in athlete healthcare to optimise outcomes and minimise injury.