Resting the brain more important than resting the body

More than 70 percent of American adults and 85 percent of teens don't get enough sleep to be sharp the next day, according to scientists at Harvard Medical School.

They say part of the problem is we are so used to being sleep deprived that we have become adept at coping with the condition. We don't realize that the purpose of sleep may be more to rest the mind than to rest the body.

Sleep helps consolidate memory, improve judgment, promote learning and concentration, boost mood, speed reaction time, and sharpen problem solving and accuracy.

To get more sleep, researchers suggest getting to bed half an hour earlier. If you can arrange a brief nap in the afternoon, it can help. They advise against sleeping late on weekends because it could disrupt your circadian rhythm, making it harder later to get a full night's rest.

The American Time Use survey shows that the main reason for lost sleep is work. But when you lose sleep, you could be 12 percent less productive the next day.

If mental sharpness is important to you, get a good night's sleep.