Canada’s clock debate is really a debate about winter mornings
Millions of Canadians will turn their clocks back on Nov. 1. Millions of others won’t. That split matters beyond the inconvenience of coordinating across time zones: sleep researchers say the permanent time some provinces have adopted could affect people’s sleep and health. Most of British Columbia, along with Alberta, Manitoba and the Northwest Territories, has stopped changing clocks twice a year, joining Yukon and Saskatchewan. Most of Ontario, Quebec and the Atlantic provinces are still scheduled to switch back to standard time. Quebec may be next to end the practice: Premier Paul St-Pierre Plamondon announced Wednesday that his government plans to stop the twice-yearly change. The province hasn’t chosen which time to keep; he said it will consult experts first. That choice is the part with health implications. Research suggests permanent standard time—the setting clocks return to in fall—better matches the body’s internal clock than permanent daylight time, which several provinces have selected. The distinction can sound technical. In winter, it determines whether people start their day with more or less morning light.Here’s how winter time could look across Canada under proposed time-zone changes.
The body doesn’t reset on command
Joseph De Koninck, an emeritus psychology professor at the University of Ottawa who has studied sleep for decades, says the spring clock change is especially disruptive. Setting clocks forward costs people an hour of sleep and pushes clock time out of sync with solar time. Light helps synchronize the body’s biological clock, and circadian rhythms adjust gradually as the seasons change. A sudden one-hour shift is harder to absorb. “We are able to adapt, but it’s not optimal for our health.” The concern grows in places where winter mornings are already dark. Edmonton, one of Canada’s northernmost major cities, could see winter sunrises as late as 10 a.m. under Alberta’s permanent daylight time.Why morning light matters
Michael Antle, head of the University of Calgary’s psychology department and a circadian-rhythm researcher, says permanent standard time would have been the better choice for Alberta. Its northern latitude and position within its time zone already mean late winter sunrises. Permanent daylight time would push them an hour later. “It’s not the choice I would have made,” Antle said. Daylight time effectively asks people to get to work or school an hour earlier relative to the sun. Antle says most people’s body clocks run slightly slow, leaving them somewhat “night owlish”; morning light helps bring those clocks forward. When that light arrives later, the body’s preferred schedule can conflict with work and school. Antle calls the resulting mismatch “social jetlag.” The evidence he cites raises questions about the trade-off. Population studies found that people exposed to later sunsets slept less and had higher rates of obesity, diabetes and heart disease. Antle also pointed to Russian research reporting more winter depression among young people while Russia observed permanent daylight time. Those findings don’t establish what will happen in every Canadian province, but they make the choice harder to dismiss as a matter of preference.WATCH | B.C. scientists warn permanent daylight time could do more harm than good:
Antle says night owls with conventional daytime jobs may have the toughest adjustment because waking early is already difficult for them. The consequences are beginning to show up in schedules, too: ski hills in Alberta’s Bow Valley are delaying their opening times this winter so staff have more daylight to prepare slopes. Schools and most workplaces have less room to shift their hours around the sunrise. The clock change itself and permanent daylight time are separate problems, researchers argue. Antle says the spring switch can leave people feeling out of sync for weeks; keeping daylight time year-round would extend that mismatch through the darkest part of winter. He’d choose permanent standard time. Keeping the twice-yearly change is a compromise, he says, that preserves later summer evenings without locking in the same winter mismatch.WATCH | Why Atlantic Canada should consider permanent standard time:
For sleep questions, CBC’s Cross Country Checkup is inviting readers to leave a comment that may be read or followed up on during Sunday’s show.Time zones in Canada are getting complicated. These maps lay them out
Canada’s time zones could become a natural experiment
Different provinces settling on different clock systems may give researchers a rare way to compare how neighbouring populations sleep and function. That opportunity comes with a catch: Alberta made its change without giving researchers the year of advance notice Antle says he would have wanted to gather baseline data.
The questions reach well beyond sleep schedules. Antle says researchers should track mental health, vehicle and pedestrian collisions, school performance and attendance, and workplace attendance and lateness. De Koninck says today’s tools can also follow people’s sleep habits over time and show how residents adapt across provinces.
But the public may deliver its verdict before those studies produce years of evidence. De Koninck expects many Western Canadians won’t know what permanent daylight time means in practice until they face winter sunrises that come much later. He says people who have tried it haven’t liked it.
The cost of lost sleep
Here’s the bigger concern: a debate over the clock can become a debate over health. De Koninck warns that sleep deprivation can bring psychological and physical problems. His blunt conclusion is hard to improve on: “You can't play with your sleep.”
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