IT’S A WINTER MORNING AND YOU’RE RUNNING LATE. You flop out of bed and lift a weary hand to peek through the blinds. The sight of overcast skies or snow and ice can make you want to slink back under the covers. But before you scold yourself for being lazy or undisciplined, you should know you’re not alone.

Have you ever wondered why it’s so much harder to get up during the winter? Or why you suddenly feel down as nights grow long? Or why you feel so cranky on cold, damp days?

Psychologists have a name for our collective winter funk. They call it seasonal affective disorder or SAD, a depression that strikes about 10 million Americans–mostly women–according to statistics from Meharry Medical College.

“As winter approaches, there’s less sunlight,” says Dr. Zia Wahid, the director of Mehaury’s residency training in psychiatry and assistant psychiatry professor. “That affects the brain’s neurotransmitters that monitor our mood.”

Wahid says SAD is a cyclical feeling of melancholy that many people who live in northern parts of the U.S. or Canada experience. It begins in mid to late autumn, but people usually shake off the depression as sunshine returns in March or April.

But before you move to sun-drenched states like Florida or Arizona, you should know there’s another type of winter sadness that can affect everyone–even those living in warmer climes. Some call it the holiday blues.

“Winter is the time of getting together for Thanksgiving, Christmas and the holidays,” Wahid says. “Many people who have lost significant others, parents or close friends begin to miss them more. For many people it brings back sad memories.”

Still others face the mental stress of meeting holiday expectations of gift-giving and creating lavish meals. When they can’t meet these demand Wahid says, they get depressed.

But the good news is there’s help. If you’re tired of feeling blue or gropping your way to the shower, you might want to consider some of the following tips. Experts say incorporating these fitness and diet guidelines into your life can help you boost your energy and beat the winter blahs. They’re also good practices to keep in mind year-round.

The key to feeling invigorated, experts say, is to keep your body and mind alert. One of the best ways to do that is through regular exercise.

“The mood of people in general is a little more upbeat when the weather is nice,” says Donna Kelly, a personal trainer with Chicago’s East Bank Club. “They can walk along the lake or rollerblade and bike.

That’s why the bad weather brings more people inside to use health clubs.” Kelly says exercise stimulates chemicals that monitor awareness in your body and improves your circulation. She says people at the club often tell her how much more alive they feel after working out.

Chicago Attorney Susan McKeever can testify to the pick-me-up power of exercise. One recent autumn morning, the working mom skipped her usual 6 a.m. routine of yoga and riding a stationary exercise bike in favor of catching a few more ZZs. By mid-afternoon, she regretted her choice.

“It’s 3:30 p.m. and I’m really tired,” said the corporate lawyer for Sidley and Austin. “I have what I call a brain lag. But I have no choice, I can’t just lie down and take a nap. I have to keep on working.”

McKeever, 34, says she grew up in an active home. She remembers family trips spent hiking, bicycling, swimming. Before she became an attorney, McKeever was a professional dancer. But after the birth of her 2-year-old son, Lester Malik, she started slowing down. Every-other-day workouts with her husband, Jeffery Larry, became snatching 20 minutes at dawn’s first light.

“It’s hard, especially when I’m really tired,” she says. “I’ll keep telling myself, `Just five more minutes [of sleep]. Just five more minutes.’ But once I get past the first few minutes of working out, I always wish I had more time to keep going.”

McKeever says she thinks better when she exercises. The afternoon haze is replaced by clear, focused thoughts. That’s the feeling that motivates:: her most days when she longs to spend just a few more moments in bed.

“I’m in a much bitter space and place when I work out,” she says. “I feel more alert and ready for work, and it lasts until I go to sleep.”

Kelly says who want to start getting in shape should follow a good fitness regimen which includes aerobic, strength and flexibility

* Aerobic workouts raise your heartbeat through exercises such as walking on the treadmill, using step machines and riding an exercise bicycle.

* Strength exercises incorporate weight routines into your workout through free-weights or weight machines.

* Flexibility means making sure your body goes through of motion doing cooldown stretches after your workout.

* “I like to compare the body to a car,” the personal trainer says. “You service your car regularly so you can keep it for a long time. The same goes for the body: It needs regular service so it can function properly.”