Becky Foerschler, Lawrence, who has seasonal affective disorder, reads by a SAD therapy light. Foerschler uses the light about 30 minutes a day. Light therapy mimics outdoor light and causes a biochemical change in the brain that lifts your mood, relieving symptoms of SAD.

It’s getting colder and darker.

If you are having trouble rolling out of bed and finding the energy that seems to bloom when the skies are sunny and warm, you are not alone.

Steve Ilardi, a Kansas University professor in psychology, says at least one-third of Americans get a case of the winter blues.

“It’s not at all uncommon for mood and energy to take a hit during the winter,” he says.

Ilardi says the main culprit is lack of sunshine, which is between 100 and 200 times brighter than typical indoor lighting. If we don’t get enough, it can affect sleep, hormone levels, energy levels, brain function and can even lead to a prolonged depression called seasonal affective disorder.

So, what can Midwesterners do to avoid it?

“They can always move to Key West,” Ilardi says with a chuckle. “But assuming it’s not feasible to spend the winter someplace sunny and warm, the most elegant solution would be to buy a light box.”

The boxes are about 20 times brighter than the brightest indoor office. Ilardi recommends the Uplift Technologies’ DL930 Day Light because it has an adjustable stand that you can put above a computer monitor. It costs about $150.

“So many people spend time every day online, so that’s a great time to get their daily bright light exposure,” he says.

He recommends using the light box for about 30 minutes within an hour of waking up.

“It has a very potent anti-depressant effect, especially for people with SAD,” he says.

Taking more vitamin D also can be helpful. The U.S. Department of Agriculture advises 400 International Units (IU) daily and may raise that recommendation to 800. Ilardi thinks those amounts are far too low. According to research, he says some people need as much as 4,000 IU, but people should check with a doctor before taking more than 2,000.

“By the end of winter, over 80 percent of Americans are vitamin D deficient, and that can affect brain function,” he says.

There is also evidence that some people can benefit from eating foods high in tryptophan, Ilardi says. Such foods would include turkey, chicken, soy products, eggs, dairy and cheese.

But the most tried-and-true pick-me-up is exercise.

“It changes the brain as powerfully in some respects as antidepressant medications, especially if it is vigorous,” Ilardi says.

That’s how Lindsey Funk, Lawrence, beats the blues. If that doesn’t work she finds a little hot spot inside Body Boutique Women’s Fitness and Health Spa where she works.

“That’s what I do during the winter is come hop into the dry sauna, which feels like Arizona, and the steam room feels like Florida,” she says. “It helps definitely during the winter.”