Lydia Denworth in Scientific American:
I usually get up by 7 A.M. and am in bed by 10 P.M. I tend to eat meals at the same times of day, too. This may sound a little dull, but it’s essential for my productivity. It’s also a schedule that rarely disrupts my body clock. And a steady clock, it turns out, just might help me and many other people avoid cancer and some other diseases, according to new research.
What I call a body clock really means circadian rhythms, from the Latin for “about” and “day.” These are the body’s internal biological pacemakers, physiological fluctuations that help us adjust to the phases of a 24-hour day by synchronizing with environmental cues such as light, dark, temperature and food intake. These rhythms affect sleeping and waking, feeding and fasting, endocrine cycles, immune function, and cell growth.
More here.