The annual ritual of turning back the clock an hour is coming up for many Canadians.
People in some parts of the country will “fall back” to standard time at 2:00 a.m. local time on Sunday. This annual practice in the fall marks the end of daylight time, allowing Canadians to gain an hour they lost. Daylight time begins on the second Sunday of March, as clocks “spring forward” an hour to take advantage of the longer periods of sunlight when the sun rises earlier in the summer.
Starting this weekend, Ontario is moving some areas in its northwest region to permanent year-round daylight time, allowing them to align with Manitoba. Other areas have announced the same plans this year, including the Northwest Territories, British Columbia, Alberta and Manitoba.
The B.C. government said in a press release in March that the shift would “improve people’s overall health, reduce disruptions for families, simplify scheduling and provide an extra hour of evening light during the winter months.”
But Atlantic Canada, parts of Quebec and Labrador, most of Ontario and most of Nunavut are among those turning back their clocks to standard time. The Parti Québécois (PQ) vowed to end daylight time on Thursday, and Quebec Premier Paul St-Pierre Plamondon referred to studies that show how the practice is “counterproductive for health and poses adaptation challenges for children.”
Meanwhile, Saskatchewan and Yukon follow standard time year-round.
Some experts are concerned about health consequences linked to seasonal time change and year-round daylight time.
“We know that switching twice a year isn’t good for us, especially in the spring, when we jump our clocks ahead an hour,” Patricia Lakin-Thomas, a professor of biology at York University in Toronto, said in a video interview with CTVNews.ca on Wednesday. “We lose an hour of sleep, and since we all need more sleep, that’s bad for us.”
Lakin-Thomas said standard time, which she called “a more natural time when we’ll be waking up closer to sunrise,” is better than daylight time. She said people in areas that have permanently switched to daylight time are “essentially jet lagging” themselves.
“We’re also switching out of standard time into (daylight time), which means we’re going away from what we think of as natural time, where ideally we would wake up around sunrise,” Lakin-Thomas said.
The time change is particularly harmful in the spring, Lakin-Thomas said, as studies show a link with a spike in “acute events” such as heart attacks, strokes, car accidents and industrial accidents.
But she said it’s not healthy to follow daylight time all year, either.
“We will be throwing ourselves away from the time that is better for our bodies, which is to wake up around sunrise and get some light in the morning,” she said.
How time changes impact the brain
The human brain has a clock that is set by light and the brain clock co-ordinates all the other clocks – or circadian rhythms – in human bodies, Lakin-Thomas said. The brain clock is in a small region called suprachiasmatic nucleus (SCN), and it contains the body’s central circadian clock. The brain clock is on the slow side and needs morning light to help it run faster, she added.
“When we get light in the late afternoon and evening, it pushes the clock later, and we stay up late,” she said. “But then we have to wake up in the morning with the alarm, and we’ve lost sleep and our bodies aren’t ready for the day.”
Lakin-Thomas said daylight time affects our bodies in other ways.
“Our bodies are still an hour behind, and our guts aren’t ready to digest breakfast,” she said. “Our muscles aren’t warmed up, ready to go. Our hormones aren’t ready to face the stress of the day.”
Year-round daylight time’s negative health effects may lead to increases in cardiovascular disease, obesity, diabetes and other chronic diseases, according to Lakin-Thomas, citing multiple studies.
“Even some cancer rates are likely to go up, and that’s because of that constant stress, which is like being constantly jet lagged,” Lakin-Thomas said. “So, we believe that year-round standard time – no switching – would be the best for our health.”
Ralph Mistlberger, an expert on circadian timekeeping and sleep, said permanent daylight time may result in the “misalignment between the internal clock, the sleep-wake cycle and our social clock.” He said the social clock refers to our work and school schedules.
“The result being that we’re getting a little bit less sleep on our work and school days, and that accumulates over time,” Mistlberger, a professor in the psychology department at Simon Fraser University in Vancouver, said in a video interview with CTVNews.ca on Wednesday. He said teens are more vulnerable to the negative effects.
“And what that is associated with, and many studies have shown … is adverse health consequences.”
With the switch to permanent daylight time, he said people are expected to get less light exposure in the morning but more in the evening, particularly when the days are short in the winter.
“In the winter, that matters, because it’s the light exposure in the morning that’s important for controlling the timing of the circadian clocks that control our sleep-wake cycle,” Mistlberger said. “If sunrise is delayed, then our internal clocks will also delay, but our social schedule doesn’t delay.
“We still have to get up at the same time.”
With files from CTV News’ Katie Griffin, CTV News Montreal’s Rachel Lau, The Canadian Press and The Associated Press
