Sleep affects our overall health, including our hormones and immune system. Neurobiological processes that occur during sleep have a profound impact on brain health, and as a result, they influence mood, energy level, and cognitive fitness. Numerous studies have shown that structural and physiological changes that occur in the brain during sleep affect capacity for new learning, as well as the strength of memories formed during the day. Sleep promotes the consolidation of experiences and ideas; it plays a pivotal role in memory, and has been shown to enhance attention, problem solving, and creativity.
Source: Harvard Health Publishing