Are you a summer athlete who isn't enjoying the holiday spirit? Have you been feeling irritable, perhaps grumpy, at people around you? Do you no longer even want to go out and socialize? Are you having trouble sleeping in the wee hours of the morning?

You may have what some athletes call "The black dog of winter" - depression.

That's not at all surprising when you consider the massive life style differences experienced when the seasons change for the summer athlete. The skin is no longer exposed to the sun's rays, so there's a huge drop in the amount of vitamin D absorbed. That's the vitamin that does a lot to ward off depression.

Plus, in winter the normal athletic activity load - training and competing - falls way down. Scientists have long known that regular exercise helps prevent depression. Plus, there's an anti-climactic letdown at the end of a season that can bring on depression in many athletes.

All these factors, and it's easy to realize why the "black dog" - more like a black cloud - descends on so many action-oriented folks during the cold months.

The problem with depression is that many times, its victims are often unaware of that they have it - which is a huge part of the problem - so the first part of fighting against this condition is to recognize its symptoms.

Depression is much more than the 'blues.' Clinical depression, measured as a condition which lasts more than six weeks, often leaves its victims feeling inferior, unworthy, tired all the time, less intelligent, and in a kind of daze. It may be hard to concentrate on words in a book - a heavy burden for someone in college who gets the illness. Very slight manifestations of these symptoms may even go totally unrecognized; in other words, the person isn't even aware of having these symptoms.

There are physical problems as well. Depending on the particular hormones affected by a particular case of depression, a person may lose weight because they've lost interest in food and rarely feel hungry; or they may gain weight and feel hungry all the time, especially at night. There may be extreme sleepiness, especially in mid afternoon. Depression may cause you to wake up several times during the night and be unable to get back to sleep, only to return to bed and sleep most of the day away, while still being tired.

Because this is often a seasonal depression, it may pass when days start getting longer again. If it's serious enough to interfere with school, work or relations with others, then a doctor's help may be necessary along with anti-depressants. But if the 'black dog' is mild enough to merely take the glow away from everything, here's how to get rid of those symptoms and restore the joy of living:

1. Exercise: Even though you may not feel like it, force yourself to go for a brisk half hour walk, do a weight session at the gym, or find some other physical activity that can be done in winter that will raise your heart rate and cause you to break a sweat.

2. Eat unprocessed and home-made foods: If you eat a lot of fast or junk foods, you have no idea whether it was prepared with oils that have gone rancid, or basic ingredients that are so old, they have lost all nutrition. Fresh food helps provide your body with the nutrients it needs; while some 'off' food ingredients can actually contribute to depression. Eating a good diet is extremely important in mild cases of depression, where many people suffer a decreased appetite and thus should make sure to eat the highest quality food when they do eat.

3. Take supplements: Essential oils like lecithin, choline and fish oil, vitamins such as D, C and the B complex, have all been proven to help fight the symptoms of depression. But remember, a complete nutritional supplement is often needed to absorb those taken separately in additional amounts.

Wina Sturgeon is the author of "Depression, How to Recognize and Grow From it," (Prentice Hall), and editor of the online magazine Adventure Sports Weekly (adventuresportsweekly.com).