The explanation offered by Arnall posited a number of culprits we could blame for the late January blues: feeling poor after Christmas, the fresh sting of failed New Year’s Resolutions, and decreased daylight hours just to name a few. Whether or not money and failure factor into it, there is certainly something to the idea that exposure to sunlight can impact our moods. A British survey reported that 79% of people feel that reduced daylight hours during the winter in temperate climates has a negative effect on their mental constitution.
Their study used mice and actually involved exposing them to light when their bodies were expecting darkness, but the results certainly highlight the vulnerability of the brain to changes in brightness. Their mice also quickly began to demonstrate behaviours associated with depression. Before you ask, a depressed mouse shows reduced movement and lack of interest in sugar and other pleasure seeking activities. While a depressed person might pursue sugar more actively than a happy one, the parallels are still striking.
The reason for the changes brought on by light can be traced back to the body’s biological clock and the daily patterns of wakefulness and sleep that tend to correspond with light and darkness. These natural fluctuations are known as circadian rhythms and they have a profound impact on the behaviour of all living things. While we are probably most familiar with the daily rhythms of our own bodies, changes also occur on the scale of seasons and years. As we grow up, we are most active at different times of the day. A five year old might wake up at the crack of dawn to watch cartoons while his parents don’t rise until mid-morning and his teenaged sister doesn’t begin to stir until just before dinner.
Likewise, seasonal changes impact the way we behave. Many animal species are thought to begin their annual migrations in response to changes in the length of the day and even the angle of the sun. Similarly, we humans are subject to the suns whims. Part of the explanation for why we don’t deal with the changes as well as butterflies, birds, and caribou could be that we evolved as an equatorial species and our internal clocks aren’t quite built for the huge swings in sunlight hours seen at more extreme latitudes. To put it on a more comprehensible time scale, a person from Hawaii might have a hard time dealing with 20+ hours of night in the extreme north if you suddenly dropped them in Iqaluit.
There are a number of things we can do to combat the winter blues, however. Sitting near windows can help us make the most of the daylight available and exercising for a few minutes each day can help get mood enhancing chemicals flowing in your body and brain. For the exceptionally lazy, there are even special lights you can buy to help trick your body into thinking the sun is still up. However you cope, it helps to know that the sadness you feel isn’t actually related to the things going on in your life. Remember, we’re all in this together… except for the Hawaiians I guess.