Some health officials call the Monday of the last full week of January the most depressing day of the year - Blue Monday for short.

Today the Canadian Mental Health Association chapter in Windsor, Ont., will hold a Blue Monday open house to help give people the tools to get through the day.

Christmas has passed, bills need to be paid, the weather is cold and the sun is scarce.

Mostly though, the blues are brought on by a lack of exposure to sunlight, registered psychologist Trang Le said.

"People tend to feel less energetic, less motivated and maybe a little more down than usual,"  Le said.

A small part of the population can suffer from seasonal affective disorder, or SAD.

SAD is energy-sapping depression that occurs at the same time each year and affects an estimated 3 per cent to 5 per cent of Americans.

Cliff Arnall began calculating the happiest and gloomiest days of the year back in 2005 while working as a professor at Cardiff University in Wales.

Arnall devised a Blue Monday formula that calculates factors such as weather, debt, time passed since Christmas, failed New Year's resolutions, low motivation and the need to take action.

While there is no scientific support for Arnall's theory, some might find the formula 1/8W+(D-d)3/8xTQMxNA itself too depressing even to contemplate.

Le says SAD can affect 1.4 per cent to 10 per cent of the Canadian population.

According to the Canadian Mental Health Association, "the shortening days of late autumn are the beginning of a type of clinical depression that can last until spring."

"The energy levels become quite low starting in September and then gradually decrease as they go along with January being the peak of that low part," Le said.

Le  suggests getting out in the sun for 10-20 minutes a day, monitoring carbohydrate intake and exercising.

"Even just 10 minutes of jumping jacks or running in one spot can again really help with your mood," Le said.

A few tips from Health Canada include:

  • If you are already active, try to maintain or increase your level of physical activity.
  • Exercise outdoors during daylight hours.
  • If indoors, exercise by a window.
  • Build activity into your lifestyle, for example, by taking the stairs or public transit and walking part of the way to work.

Treatment options include light therapy and medication.

For years Tim Seguin has struggled with addiction problems, depression and more recently seasonal affective disorder.

Seguin is getting treatment for his addictions and sticking to a routine.

"I just wanted to sleep and you don't want to do anything. It's hard to shake when it gets a hold of you," he said. "I didn't want to feel like that all the time. Feeling, sad, depressed, lonely."

With files from Associated Press