Sleep is crucial for health, recovery, and regeneration, affecting muscle recovery, hormone secretion, the immune system, and exercise performance. This chapter delineates the intricate physiology of sleep, emphasizing its actively modulated nature and its role in optimizing metabolic processes. Despite the fact that regular exercise is essential for good sleep, athletic populations often experience poor sleep and sleep disturbances. The interaction between exercise and sleep is also discussed concerning the risk for muscle injuries and inflammatory responses, highlighting the role of sleep in maintaining and restoring skeletal muscle physiology and its influence on inflammatory activity. Moreover, the detrimental effects of sleep deprivation on exercise performance and recovery are explored, demonstrating its association with decreased athletic performance due to increased physiological demand and altered energy substrate utilization. Finally, the influence of nutrition on sleep is analyzed, illustrating how nutrients can entrain the body’s circadian rhythm and affect sleep initiation and maintenance, thereby promoting recovery.