Why is it, an insomnia sufferer recently wrote to Ask The Savvy Insomniac, that my insomnia always seems to get worse in the winter? “Erratic” describes my sleep right now. Some mornings I wake up like a bear coming out of hibernation! It’s all I can do to haul myself out of bed. Then when I do get up I’m low on energy and my mind’s in a fog. Some nights I fall asleep early (and wake up as early as 3!), and other nights I can’t fall asleep till 1 or 2.
If there’s a seasonal pattern to your insomnia, reduced light exposure could be the culprit. People in northerly latitudes are exposed to little daylight in the winter, and this can have a negative effect on circadian rhythms and worsen sleep.
Absence of daylight can interfere with the normal rhythm of your body’s secretion of melatonin, a hormone under circadian control. Melatonin secretion typically begins about two hours before you fall asleep and ends at wake-up time. But melatonin is light sensitive. Without the benefit of early morning light, melatonin secretion may be prolonged, making you feel sleepy and less alert.
Absence of light in the evening, on the other hand, can cue melatonin secretion to start soon after dinner. You nod off early and then awaken too early in the morning.
Bright Light Therapy: What and How
The recommended treatment for seasonal sleep disorders involves a light box—bright fluorescent bulbs encased in a box with a diffusing screen. The box is designed to deliver light at the intensity of sunlight—10,000 lux—in a way that’s safe for the eyes, with a minimal amount of ultraviolet (UV) light.
When using a light box, set it on a table or a desktop so the light is aimed at you but you’re not looking directly into it. Use it while doing any stationary activity: reading, eating meals, working at the computer, watching TV.
Timing Is Important to Success
If your main complaint is oversleeping and feeling groggy in the morning, schedule sessions with the light box early in the morning when it’s still dark outside—say, at 6:30 a.m. Thirty minutes a day is sufficient for many users (and is generally sufficient for a majority of people with Seasonal Affective Disorder, or SAD). But people vary greatly in their sensitivity to light. Some may need more exposure to bright light; others, less. Also, the lower the light intensity (some light boxes emit light at 2,500 lux), the longer your daily therapy sessions will need to be. The goal is to enable more efficient sleep and increase your daytime alertness.
If your main complaint is falling asleep too early, schedule your light therapy in the evening between 7 and 9 p.m. Use the light box on a daily basis to keep your circadian rhythms regular and put off sleep until a reasonable hour.
Do you find that your insomnia varies with the season? If so, when is your insomnia worse?