Feeling deficient in sunlight


Yesterday and today were gorgeous. The sun was out, the sky was mostly blue with the occasional puffy cloud. The sunshine was much appreciated, and I took advantage of the warming rays to go for a short walk. Yesterday on the morning news they said that to that point we’d only had 20 hours of sunshine (not overcast) so far this February. In an average February the Toronto area would see about 110 hours over the full month. So we’re a little deficient this year.

If you’re like me, long stretches of overcast skies can start to wear at you. I find the winter rather long, and beginning usually in January I begin to itch for the spring to arrive (and it’s not just because, as an Ontario naturalist, that’s when all the activity starts, nor is it strictly that I find the minus temperatures difficult to enjoy being out in).

Blue sky

Many people will go through periods of the “winter blues”, characterized by low energy and depressed enthusiasm for things. A more severe form of this is SAD (Seasonal Affective Disorder) or SSAD (subsyndromal SAD, slightly milder), and sufferers show symptoms of mild or severe depression, occasionally (but rarely) even becoming suicidal. It’s generally associated with decreased sunlight during the winter months, both in the form of shorter day lengths and increased numbers of cloudy days. The exact mechanism affecting the brain is unclear.

Highway-side wetland

In northern latitudes it can be very common. Here in Ontario, studies have shown that 2 to 3% of the population suffers from SAD in the winter (no mention of whether most of these live in the northern part of the province). In Alaska, nearly 9% of people may suffer from SAD, and a further quarter of the population may have the less severe SSAD. An even higher 20% of people in Ireland and Scandinavia may be affected by SAD. Some studies have suggested there may be a genetic basis to the disorder (Icelanders, including those of Icelandic descent in other regions of the world, are resistant to the disorder), and research has found that women are up to eight times more likely to be affected than men (think it has anything to do with our natural hormonal mood swings?).


The treatment? Usually exposure to specially designed lamps, which help compensate for the lower natural light levels. Sometimes antidepressant medication is also prescribed. The lightbox mimics light levels on a partly-cloudy day (about 10,000 lux, whereas cloudy days are around 3,000 lux, sunny days 50,000 lux, and indoor light only about 400 lux). About 30 minutes a day exposed to this lightsource helps most sufferers. Since we don’t know for sure why people suffer from SAD, we can’t say for sure why more light helps, but there’s substantial proof that it does.

People with milder symptoms (the “winter blues” or SSAD) may simply be helped by spending more time outdoors, particularly if combined with regular exercise, such as going for a walk during your noonhour. Taking vitamin supplements, particularly vitamin D which your body needs sunlight to produce and so many people are deficient in during the winter, may also help.

Happy cat

My personal belief is that the cats have got it right. Look at this guy, doesn’t he look like one happy cat? And it’s probably because he’s been able to stave off SAD by lying in sunny puddles all day. I enjoy a good curl-up in the sun, too, but unfortunately it’s much harder to find a human-sized puddle than it is a cat-sized one.


The days are getting longer now. December 21 was the winter solstice, the shortest day of the year. The spring equinox, the day when day and night are equal, will be March 20. Today in Toronto sunrise was at 7:16am and sunset at 5:48pm. In two weeks, at the end of the month, those times will be 6:56am and 6:04pm – 36 more minutes of daylight. By St. Patrick’s Day, just a month from now, sunrise will be 7:26am (don’t forget daylight saving) and sunset 7:26pm (there’s a neat coincidence) – nearly an hour and a half more daylight than we have now. So cheer up, fellow winter-weary, there’s light on the horizon!