Human sleep and immunity: The role of circadian patterns.

It is well established that sleep promotes health and welfare. Literature data suggests that sleep is a recurrent resting state that performs multiple biological functions, such as memory consolidation and regulation of glucose, lipid metabolism, energy metabolism, eating behavior, and blood pressure, besides, regulating the immune system. These immunological functions depend on regular sleep and circadian rhythms, as both impact the magnitude of immune responses. Circadian rhythm is the 24-h internal clock in our brain that regulates cycles of alertness and sleepiness by responding to light changes in our environment. It encompasses physical and behavioral daily oscillations. Sleep deprivation and circadian misalignment affect immunity, and both have been related to adverse health effects and chronic diseases. Studies have shown that individuals with regular and consistent sleep patterns have a more effective immune response. Thus, understanding how sleep disturbance will affect the immune response is vital in developing interventions to prevent the health burden of irregular sleep patterns and circadian misalignment, favoring a homeostatic immune defense to microbial or inflammatory insults. Therefore, the scope of this chapter is to explore evidence that regular circadian rhythms and sleep patterns are needed for optimal resistance to infectious challenges.