With the arrival of fall comes the revival of a debate as predictable as the falling leaves: should we stop changing the clocks twice a year and just stick with one time year-round? And if we do, which should it be?
That debate has taken on new resonance because starting this year, all of western Canada will stop moving their clocks back. Saskatchewan did away with the time change in the 1960s and keeps standard time year-round. But now British Columbia, Alberta, Manitoba and part of northwestern Ontario will all remain permanently on daylight saving time year-round, trading darker winter mornings for later sunsets.
The rest of Ontario, Quebec and Atlantic Canada will continue to spring forward and fall back for the foreseeable future. The New Brunswick government has said it is not considering making any changes.
Daylight saving time was first introduced during the First World War in an attempt to conserve coal and fuel — despite what you might have heard it has nothing to do with farmers. In fact, farmers have usually been its loudest opponents, since cows and crops don’t really care what our clocks say. The effects on energy use were debatable back then, and essentially non-existent today due to changes in technology and human behaviour that have largely offset any benefits.
But the twice-yearly change, and especially the spring forward, has serious health effects. Every spring, there is an increase in heart attacks, strokes and fatal car accidents as our bodies struggle to cope with the sudden loss of an hour’s sleep and the resulting mismatch between our internal biological clocks and the external environment. That, along with a general desire to hang on to more evening light, has led to the current decisions across Canada to stick with daylight time.
That may be the wrong choice, however. While lighter evenings make it easier to exercise, socialize or shop after work and school, new research in the Canadian Medical Association Journal shows that keeping standard time would be better for our health.
“Ending the clock change solves one problem, but it creates another decision: which time should we live on year-round?” said study author Raymond Lam, a psychiatrist at the University of British Columbia. “The health evidence points to standard time, largely because morning light matters for our body clocks, sleep, and mood.”
Morning light helps synchronize the body’s circadian clock, while evening light delays it. So moving to permanent daylight saving time works against circadian alignment during winter by reducing morning light while extending evening light. This can have important effects on mood and sleep.
“Our biological clocks need morning light to stay synchronized with the 24-hour day,” said study author Ralph Mistlberger, a psychologist at Simon Fraser University. “Permanent daylight saving time moves that light an hour later just when winter mornings are already darkest.”
Children and adolescents would be hit particularly hard by permanent daylight saving time. In addition to the increased safety risk of travelling to school in the dark, they are more vulnerable to the effects on sleep, because puberty naturally shifts sleep timing later while school still starts early. Shift workers, public transit users, pedestrians and cyclists and people living in rural or lower-income communities with poorer lighting and transportation infrastructure will also feel more of the negative health effects.
Whatever time is chosen, the authors say governments should monitor its effects and take steps to mitigate the harms.
“Time policy is a public health policy,” said Alexandra Choi, medical health officer with Vancouver Coastal Health. “If governments choose permanent daylight saving time, they should plan for the consequences before the first winter — from safer morning travel and flexible start times to monitoring sleep, mental health, and injuries.”
But even if permanent daylight saving time is adopted across Canada, it may not last long if history is any guide. The United States implemented it in 1974 during the oil crisis, but reversed the policy a year later because it proved unpopular (though a bill to try again recently passed in the House of Representatives). Russia and Chile also cancelled short-lived experiments with permanent daylight saving time after public opposition.
