Sleep and Aging

Researchers believe that two body systems -- the sleep-wake process and our circadian biologic clock -- regulate our sleep. They program our bodies to feel sleepy at night and awake during the day. The sleep-wake process works by balancing the amount of sleep a person needs based on the time spent awake. Our circadian biologic clock is a 24-hour body rhythm affected by sunlight. It regulates hormones such as melatonin, which is secreted during the night and promotes sleep, and other processes like body temperature. Sleeping at a time that is in sync with this rhythm is important for healthy sleep.