What is our body's "internal clock"?

What is our body's "internal clock"?

Gary Feldman (Medical Director, Stramski Disorders Center, Miller Children's Hospital ) gives expert video advice on: What are the benefits of sleep for children?; What is a normal sleep pattern?; How much sleep does my child need every day? and more...

The body's internal clock is an innate system allowing you to realise subconciously when it is night and day. There are certain things that keep your internal clock syncronized. For instance if you took an individual and put them in a room without outside stimulation and you kept the light on indefinitely, you'll find that the body's internal clock letting you know when you feel tired and when you wake up naturally, will be around 25 hours and will progressively increase. So if you left someone in a room for a number of days, you would find in fact that after a few days they would actually want to sleep in what would be the day time and would want to be awake in what would be the night time, and then given enough time it would cycle back through to night time. So the factors that help you synchronize your internal clock, what we call the Circadian rhythm, are basically: exposure to light, regular meals, and activity. And these things are really what keeps our clock on schedule.