Image courtesy of Prevention

If your smile seems to be drooping along with the temps, it's probably not your imagination. Seasonal affective disorder (SAD), a reaction to reduced sunlight, affects up to 20% of Americans--and three quarters of those affected are women. Lethargy, overeating, and being bummed can spell disaster for your health, but you can beat it.

Here's how.

Take a sunny stroll

Go walking in a winter wonderland! Sunlight-drenched strolls help clear your SAD symptoms by giving you a boost of vitamin D, which most of our bodies are craving (especially in gray weather.) D deficiency has also been linked to an increase in headaches in the fall and winter, say researchers in a Journal of Headache and Pain study.

3 Common Myths About Depression

Shed some light

The dark gloom of winter dampens your body's production of serotonin, a mood-regulating neurotransmitter. Rejuvenate it with a light box that features blue light-emitting diodes (LEDs) with a peak wavelength of 470 nm. They're more stimulating and produce less glare than white light boxes.

Burn calories for warmth

We know it's tempting, but resist the urge to hibernate until spring. A study from Vanderbilt University Medical Center found that women moved the least in December, January, and February, burning 10% fewer calories than they do in summer. Push yourself to get some exercise--your heart and head will thank you.

Do a weird workout

Combine the benefits of light and exercise with a new workout called "Lighten Up", specifically designed to cause winter cheer. These classes, offered at New York Sports Club in select cities, combine high-intensity intervals with light therapy meditations for seriously happy oms. If you're not a member, train outside in the morning or with a light box for the same effect.

The Yoga Workout That Makes You Lighter, Happier and More Joyful

Pump up your produce

The secret to happiness may be at the end of your fork. People who ate the most fruits and veggies were less likely to be anxious, depressed, and show signs of other mental disorders, according to a study of 80,000 people. The more produce people ate, the happier they were.

Sip your blues away

It's hard to beat the health benefits of tea: Some kinds can help prevent cancer, while others combat diabetes. But if your mood needs to be soothed, choose chamomile. A University of Pennsylvania study found that chamomile supplements significantly eased anxiety symptoms. Bonus: You'll get nice and toasty at the same time.