Delayed-onset muscle soreness can hinder athletic performance by impairing recovery processes. Adequate and restorative sleep plays a crucial role in regulating hormonal balance, cardiovascular adaptation, and muscle tissue repair. However, intense exercise often disturbs sleep quality, thereby prolonging recovery. This study aimed to investigate whether improving sleep quality through melatonin supplementation could indirectly influence recovery parameters, including flexibility, cardiovascular indices, and muscle damage biomarkers, in active athletes. Twenty-four male athletes (18-25 y) from multiple sports, including soccer, basketball, volleyball, and athletics, participated. Participants (N = 24) were randomly assigned to a Melatonin group (3 mg/d for 5 nights before sleep at 10.00 PM, n = 12) or a Placebo group (n = 12). All subjects performed 30 min of eccentric plyometric exercise. Sleep quality was monitored using Fitbit Charge 3 devices, which have been validated against polysomnography for field use. Blood samples were collected pre-exercise and at 24-, 48-, 72-, and 96-h post-exercise to determine CK, IL-6, TNF-α, LDH, MYO, and AST levels. Melatonin supplementation significantly improved total sleep duration, flexibility scores, and resting heart rate compared to placebo (p < 0.05). However, melatonin did not produce statistically significant effects on muscle damage biomarkers (CK, LDH, MYO, AST, IL-6, TNF-α). These findings indicate that melatonin primarily enhances sleep and may aid cardiovascular recovery, with limited direct influence on biochemical markers of muscle damage after acute eccentric overload exercise. Low-dose melatonin supplementation may serve as a supportive, non-pharmacological strategy to improve sleep quality in athletes. While it did not significantly reduce biochemical indicators of muscle damage and cardiovascular recovery, the improved sleep-related recovery suggests potential indirect benefits for overall post-exercise adaptation.
Aykora et al. (Mon,) studied this question.