Variations in the sleep–wake cycle from childhood to adulthood: chronobiological perspectives

: Changes in the sleep–wake cycle across development from childhood to adulthood, typically involve a steady shortening of the sleep period and a delay of sleep phase, with a period of more rapid change across adolescence. Accompanying these changes is the maturation of neuroendocrine rhythms such as melatonin, cortisol, and pubertal hormones. These endogenous rhythms are closely associated with behavioral changes in rest and activity rhythms, although environmental factors such as light exposure and academic and social demands likely play an interactive role. Other behavioral aspects, such as physical activity and eating behaviors, are also associated with changes in sleep–wake rhythms, and may be mediational factors in the development of physical illnesses. The sleep–wake cycle and related factors are implicated in the development of mental illnesses. There are several potential avenues of future research that may be valuable in terms of improving interventions and treatments for both mental and physical illnesses.