Do you feel blue whenever winter arrives? Maybe when the cold air hits you’re also less energetic than you typically are from the spring through fall. You could have Seasonal Affective Disorder (SAD).

SAD is a seasonal disorder commonly known as winter depression. People come down with the condition primarily due to sunlight deprivation. That’s why it’s much more likely a person in the northern part of the U.S. would be diagnosed with SAD than someone in, say, Florida. During winter, the sun’s light is much less concentrated in the northern hemisphere and this causes a reduction in heat distribution. The lack of direct sunlight and heat causes people to experience SAD.

To combat this condition, doctors have used infrared saunas, a type of light therapy that works wonders to treat SAD. In general, when treating SAD with light, doctors will sit the patient a few feet away from a full-spectrum fluorescent light for about 30 minutes, which is roughly 12 times brighter than a room’s incandescent light. The number of sessions will depend on the doctor. The light is believed to directly impact the brain’s chemicals that affect a person’s mood.

About 10 million people in the U.S. are said to have SAD. Another 10 to 20 percent typically have mild SAD. While only about 6 percent of victims require hospitalization, it severely affects the quality of life of 100 percent of its victims.

Along with helping someone suffering from SAD, there are many other benefits of infrared saunas, such as their ability to also help with many other chronic conditions such as high blood pressure, congestive heart failure and rheumatoid arthritis. It’s also a great way to burn calories.