In northern climates when the heavy snows fall and the sun moves south, many people find their moods shift from upbeat to downright depressed. The severe form of winter depression–called seasonal affective disorder, or SAD–affects at least two million North Americans. Another thirty-nine million experience milder symptoms of moodiness and extended sleep patterns that somewhat resemble hibernation.
Overeating, sleeping for prolonged periods, mood swings, carbohydrate cravings, and weight gain during winter months may be more than just symptoms of cabin fever. They can suggest a biochemical reaction caused by a lack of exposure to sunlight.
Like all living things, we humans are sensitive to the seasons and sunlight. We secrete a hormone called melatonin, which helps us sleep at night and stay awake during the day. Melatonin production is directly linked to sun exposure. So, as the days get shorter during the winter, our bodies produce more and more melatonin and we can literally feel like going into a cave and Hibernating.
Many SAD sufferers manage their seasonal depression with daily exposure to full-spectrum lamps or light boxes. By getting daily doses of natural light, they can fool their brains into thinking it’s summertime, and their need to sleep decreases.
Recent research shows that timing these light therapy sessions to our natural biological clocks is even more beneficial than usage during the day. Exposure to natural spectrum bright light for thirty minutes on awakening is twice as effective as evening sessions, and one study found this practice actually had an 80 percent chance of sending SAD into remission.
If winter blues are getting to you, consider investing in a full spectrum lamp and use it first thing in the morning–because SAD is for the bears.