Do you feel down in the dumps, have less energy and put on a few pounds during the dark, shorter days of winter? You may be suffering from the "winter blues" or a more severe form of the winter blues called Seasonal Affective Disorder or SAD. One in five of us suffers from this problem. Symptoms can include an increase in sleep of up to four hours a day, a serious case of the munchies, and a desire to withdraw, almost like a bear entering hibernation for the winter.

In 60 to 80 percent of cases, the cure for this potentially disabling condition is to make up for the reduced daylight hours in winter through daily exposure to a light therapy lamp or SAD lamp. There are two types of SAD lamps to choose from, high intensity and blue LED.

High intensity SAD lamps (e.g., http://www.up-lift.com) are UV-filtered fluorescent lamps with low flicker ballasts that generate light about 20 times brighter than the average home or office. Blue LED SAD lamps (e.g., http://www.litebook.com) use LED arrays to emit blue light that suppresses the sleep hormone melatonin believed to be involved in causing SAD.

High intensity lamps are used by sitting 12 to 15 inches in front of and slightly below them, with eyes averted downward. Position and distance are less critical with blue LED lamps, although it is still important to maintain an unobstructed pathway to your eyes. Carry on eating, reading or writing as you normally would.

Treatment for most people should begin in the fall and continue through till April when the outdoor light is sufficient to provide for their needs. An early start on light therapy in the fall can reduce or even prevent symptoms of winter SAD. Exposure periods range from 15 to 60 minutes a day, preferably in the early morning.

Besides its beneficial properties in treating seasonal depressions, bright light can also be helpful with seasonal overeating and weight gain that occur without depressed mood. Some non-seasonal depressions, fatigue, insomnia in people over age 50, and sleep cycle disruptions caused related to shift work and jet-lag can also be treated with light therapy. Although side effects are rare, they can include headaches, eye strain, irritability or anxiety, and restlessness.

Before diagnosing yourself with SAD, and running out to buy a SAD lamp, see your family physician. He or can she tell you if there are any contraindications to using the lamps such as eye disease or taking light-sensitive medication. Your physician can also help diagnose medical disorders that masquerade as SAD. These include under active thyroid function, low blood sugar, and chronic viral infections.

Next, consider renting a lamp for two weeks to find out if the treatment is effective. Although the response rate for high intensity SAD lamps is high (less is known about the efficacy of blue LED lamps), you could be one of the non-responders. As a final consideration, find a reputable dealer who will allow you to apply the rental payments toward the purchase price.