The 8 Hour Idea

Where did the idea that we need 8 hours of sleep come from? Anthropologists believe that the eight hours of nightly sleep required by most people today were genetically programmed when the first humans walked the earth along the equator - where it is dark for just over eight hours per day. Sleep problems arise when we step out of sync with this circadian rhythm that would otherwise wake us up naturally with the rising sun and send us to bed soon after dark.

* Source: Healthwise, Fall 1995