The master clock that drives our daily lives remains steady even as we age, a new study shows, contradicting conventional wisdom explaining why older people frequently suffer from sleep disorders.

Scientists had thought that in humans, the period of the master clock was about 25 hours, although some studies found it to be as short as 13 hours or as long as 65 hours. Age was thought to hasten the master clock, robbing the elderly of their sleep and causing them to awake early.

In humans and other mammals, the master clock is located deep within the brain's hypothalamus in the suprachiasmatic nucleus, called SCN. The SCN works to keep the body on time, like an internal metronome, and controls several body functions while also interacting with the mechanisms controlling sleep.