If you do one thing this month...open your shades as soon as you wake up

Experts say it can prevent fatigue and improve your mood all day long.

When it takes three hits of the snooze button to get out of bed, you might feel like heading straight for the coffeepot, but try raising your blinds first. Natural light is an important cue for your internal clock, the mechanism in your brain that tells you when to do everything from sleeping to eating. And research shows that early-morning exposure to the sun's rays helps set that clock, making you more alert, increasing your energy throughout the day, and even boosting your metabolism. This becomes more important in winter: "Fewer daylight hours can make you feel more sluggish and may increase feelings of sadness or seasonal depression," says Michael Terman, Ph.D., director of the Center for Light Treatment at Columbia University Medical Center. If there aren't many rays creeping into your room, turn on a white fluorescent lamp and you'll be ready to face the day and the season.