Chronotype and Exercise Performance: Physiological Mechanisms, Practical Applications, and Future Directions—A Narrative Review

Chronotype, defined as an individual’s circadian preference for sleep, wakefulness, and daily activities, has emerged as a potential modifier of exercise performance. This narrative review aimed to synthesize current evidence regarding the relationship between chronotype and exercise performance, with particular emphasis on strength- and endurance-related outcomes. Relevant literature was identified through searches of major electronic databases and manual screening of reference lists. Current evidence generally suggests superior acute strength-, power-, and neuromuscular-related performance during the late afternoon and early evening, particularly when exercise timing aligns with individual chronotype preferences. In contrast, evidence regarding endurance performance remains more variable, with observed effects appearing to depend on exercise modality, participant characteristics, habitual training time, and chronotype assessment methods. Proposed mechanisms include circadian fluctuations in core body temperature, hormonal regulation, neuromuscular activation, metabolic function, skeletal muscle molecular clocks, and sleep–wake behavior. From a practical perspective, chronotype assessment may contribute to individualized exercise prescription, training scheduling, and competition preparation, although current evidence suggests its use as a complementary rather than a standalone strategy. Overall, chronotype appears to influence exercise performance through integrated physiological, molecular, and behavioral pathways. However, whether aligning training with chronotype produces superior long-term physiological and functional adaptations beyond appropriately designed training programs remains unresolved. Future well-controlled randomized longitudinal studies integrating molecular, physiological, and performance outcomes are needed to determine whether chronotype-aligned exercise provides clinically meaningful long-term adaptations.