At first, she thought it was post-holiday blues, since her mood tended to dip around the time festive, glowing December gave way to bleak, ashen January. • "I thought it was all the gray," said Barb Churchill, 51, of Minnetonka. "The trees, the ground, the sky ..."

The problem, she noticed, recurred every year. She would feel sluggish, foggy, tempted to overeat -- difficult emotions, even for a professional life coach like Churchill ( knowledgeable about improving well-being through lifestyle choices. But her trusted habits -- exercise, yoga, balanced diet -- didn't cut through the fog. Her early morning routine of conscious breathing, meditation and gratitude practice failed to generate her accustomed a.m. energy.

"I'm [normally] a pretty high-energy person, but I was just a ball on the couch," Churchill said. "It got to a point of where I didn't want to do anything. I would have days where I couldn't even function. I would be unable to focus, just depressed, just down. I couldn't put my finger on it, because life was good, you know?"

The first few times it happened, she toughed it out until April, when relief mysteriously arrived. Then about six winters ago, on a friend's recommendation, she started spending time each day in front of a specially designed white light.

"I'm not kidding you, that was a godsend," she said. "Within about 10 days, I noticed I had more energy."

Minnesotans love to embrace winter, to boast about tromping through cold snaps on little more than a good parka and a set of jumper cables, to humblebrag about the vigor required to endure meteorological smiting that would have less hardy folks googling "Florida condos" by the time they finished shoveling the season's first snowpocalypse.

But some people, like Churchill, struggle with gloom, lethargy, food cravings and the urge to curl up on the couch with a plate of cookies and a Snuggie until the lilacs bloom.

"Winter blues" is one term for the milder form of this funk. More severe depression, strong enough to interfere with work, sleep or other functioning and possibly warrant clinical help, was identified in the 1980s as Seasonal Affective Disorder, or SAD. They're both linked to light deprivation, which is thought to mess with the brain chemicals that influence moods and sleep patterns.

Typically, winter depression reaches its full impact during the Northern Hemisphere's dimmest period, when the sun's low-slung path across the sky is so truncated that many people travel to and from work in darkness. For some sufferers, like Churchill, December offers enough merry distraction to push the problem off until January; for others, the condition exacerbates existing sadness or memories already associated with the holidays themselves. Some people start to feel twinges by Labor Day, or even as early as midsummer, when the days first start imperceptibly shrinking. Experts estimate that these mood disturbances may affect 7 percent or more of the population -- the rate might be higher at Minnesota latitudes -- though it's hard to know how many people suffer at an unreported, subclinical level.

If you've experienced mood slumps of your own, one way to tell whether they're seasonally influenced is to trace the timing, said Dr. Scott Crow, a psychiatry professor at the University of Minnesota who has focused on mood disorders. Many Minnesotans find March dreary, when winter sports are winding down and spring is dragging its muddy feet (i.e., "cabin fever"). But seasonal mood sufferers start to feel better as the days lengthen and the sun's rays intensify.

Until that solar help arrives, expert-endorsed treatments include the remedy that worked for Churchill, a special broad-spectrum or natural-spectrum light designed to resemble sunlight. Preliminary research indicates that these lights can bring relief for people who sit in front of them, usually for half an hour first thing in the morning, at least a few days a week.

"Within several days to a week or two, their mood is greatly improved," Dr. William Weggel, a psychiatrist at the Mayo Clinic Health System's locations in Chippewa Falls, Wis., and Eau Claire, Wis.

Weggel and other experts recommend using a light labeled 10,000 lux (a measure of light intensity). The Center for Environmental Therapeutics (CET, at recommends other criteria and sells a 12.5-by-16-inch model for about $180. Other 10,000-lux models, many of them smaller, are available elsewhere online for less than $100.

More research is needed to fully understand how the lights work, Weggel said. In the meantime, most insurance policies won't cover them.

Other potential remedies include treatments used against regular clinical depression, such as psychotherapy and anti-depressant medications. Exercise has been shown to help boost mood, especially in this case when performed outdoors. Researchers at Columbia University Medical Center have seen positive results from negative-ion generators (which the CET also sells and provides criteria for evaluating). Some swear by Vitamin D supplements, although "the evidence doesn't point to that," Weggel said.

Churchill is content to relax before her light box, imagining herself sunbathing on a warm beach.

"I almost feel like a plant that's wintering over," she said. "Just stick me in front of a light for a couple of times a day, and I'll be fine."

Katy Read • 612-673-4583