I suffer a mild form of Seasonal Affective Disorder, where the diminishing daylight depresses my mood.
As humans have done for eons, I celebrate the seasonal festivals that brighten the dark, especially those including candles and lights. There’s evidence that humans have been lighting the dark for as long as they’ve had fire, especially in the parts of the world where daylight dwindles in winter. But with the advent of electricity, humans have been lighting the night to an unhealthy extreme.
Growing epidemiological evidence reveals that people who experience too much exposure to nighttime light are at increased risk for serious health issues, including cardiovascular disease, obesity, diabetes and certain cancers – most notably cancers of the prostate and breast. Too much exposure to nighttime light interferes with sleep, and the prevalence of sleep deprivation in the industrialized world appears to be on the rise – with significant consequences for public health, safety, and quality of life.
The problems caused by nighttime light exposure are significant enough to attract scientific inquiry. Scientists have located the control center of our biological clocks near the anterior hypothalamus, and they’ve learned that our clocks are synchronized with the 24-hour day by the environmental cues of light, loco-motor activities, and mealtimes. Scientists have also identified ten genes essential for mammalian circadian clock function.
Doubtless, there are biochemists already at work compounding medicines to chemically readjust our biological clocks. But like so many ills in modern life, there are alternatives to medical intervention. Sleep is one. Starlight is another. I make sure I get enough of both until the earth turns the corner in its orbit, spinning back toward the sun. While I don’t like the early nightfall of late autumn, I do appreciate that the long dark evening makes it easier for me to go to sleep early and to stay asleep longer. I sleep better in winter, and oddly, I don’t mind starting my day in the dark.
But the dark of the winter night isn’t really that dark – especially in rural Vermont, where light pollution is rare. Ironically, without artificial lights, the winter night sky becomes vivid with stars, and moonlight casts shadows across the landscape, especially when snow covers the ground.
I’m not aware of any scientific evidence demonstrating that standing under the dome of the sky in the natural light of the winter night is an effective treatment for the doldrums that accompany this time of year, but it helps me. Turning off the bright lights helps me plug into the universe, which makes me feel better, even in the dark of the year.
