调整你身体时钟的五种方法

When you go to bed and when you get up are keystones to restful, refreshing sleep. Once you learn to synchronize your body's biological clock, your body will know when to sleep and when to be alert.

　　1. Wake at the Same Time Every Day. A good night's sleep actually starts in the morning. The second your eyes flutter open, light shoots down the optic nerve and into the brain's biological clock. There it stimulates the production of a smorgasbord of hormones that regulate growth, reproduction, eating, sleeping, thinking, remembering —— even how you feel from minute to minute. “Sunlight activates the brain," says Frisca L. Yan-Go, M.D., medical director of the UCLA Sleep Disorders Center. And activating it at the same time every morning synchronizes your body's biological clock. Then your body has a clear direction that at midnight it's supposed to be asleep and at noon it's supposed to be awake. Wake up at a different time every day and the clock is out of sync. You feel groggy and hangover for hours, and even when you start to feel a bit more alert after that first Starbucks, you really never achieve the mental edge of which you're capable.

　　2. Hit the Sheets Only When Sleepy. No, not just tired. Sleepy, as in your eyes are droopy and you keep losing track of what people are saying to you.

　　3. Get Up. Sleeping from 11:30 P.M. until 2:00 A.M., tossing and turning until 4, then sleeping until 6 gives you eight hours in bed but only 4 1/2 hours of sleep. That's a huge mismatch that can actually inhibit your sleep drive and cause insomnia all by itself. To prevent that from exacerbating your sleep issues, when you wake at 2:00 A.M., get up and go read a book in the living room. Being up increases your sleep drive —— which just could make you sleepy enough to actually fall asleep when you return to bed. One caveat: Don't stay in bed when you're awake. A part of your mind will begin to associate the bed with being awake rather than being asleep. And that can turn on a nasty "I'm-not-going-to-sleep!" anxiety that will rev your engines whenever you get into bed. It's one of the most insidious —— and potent —— causes of chronic insomnia.

　　4. Give Yourself an Hour. The one right before bed. You need it to wind down and transition from the woman-who-can-do-everything into the woman-who-can-sleep. Unfortunately, most women are not giving themselves one single second. According to the 2007 National Sleep Foundation poll, during the hour before bed, around 60 percent of us do household chores, 37 percent take care of children, 36 percent do activities with other family members, 36 percent are on the Internet, and 21 percent do work related to their jobs.

　　5. Beware Sunday Night Insomnia. Staying up late on Friday and Saturday nights and sleeping in on Saturday and Sunday mornings is frequently the gift we give ourselves on weekends after a hard week at work. Yet that little gift —— small as it is —— is enough to screw up our biological clocks. Even if you get to bed early on Sunday night, you will not be ready to sleep, and you will not end up being the happy camper you were expecting come Monday morning.