An Ottawa sleep expert warns daylight saving time has a dark side, with health risks that may be costing the city more than an hour of daylight.
Clocks in Ottawa and much of Canada are about to turn back an hour, marking the end of daylight saving time. But, as more provinces debate keeping or scrapping the practice, the question remains: Is it time to let daylight saving end for good?
New consultations in Quebec could tip the scales, with that provincial government seeking public input before moving forward on legislation to abolish the twice-yearly shift.
Dr. Rébecca Robillard, co-chair of the Canadian Sleep Research Consortium and director of sleep research at the University of Ottawa’s Institute of Mental Health Research, argues the issue isn’t about personal preference. “This is a matter of public health, not opinion,” she said, pointing to scientific evidence that the time change does more harm than good.
“On winter days when the sun rises later, our biological clock is shifted later, causing a mismatch (with) our social clock,” she said. “This forces us to get up earlier than our body is ready.”
By widening the gap between our internal clocks and the natural day-night cycle, permanent daylight saving time could worsen our “social jet lag,” leaving people feeling out of sync, she said.
“If we adopted permanent daylight saving time, in winter, it would be even worse,” Robillard said.
“Most people (would) start school or work before sunrise for a third of the year,” an adjustment that could impact health, productivity, and well-being across the country.
Here’s a closer look at what daylight saving time means for Canadians — and why many are ready to see it end.
Evening Update
When do clocks roll back this year?
Ottawa residents will set their clocks back an hour at 2 a.m. on Sunday, Nov. 3, 2024. It’s the annual fallback after Halloween weekend, giving everyone a bonus hour of sleep. For the forward thinkers, daylight saving time resumes at 2 a.m. on Sunday, March 9, 2025, when we “spring forward” and lose that hour again.
What does the time change mean for sunset in Ottawa?
When clocks roll back, Ottawa will gain an hour of morning light, but sunset will arrive noticeably earlier. Following the time change, sunset in Ottawa will shift from about 5:50 p.m. to approximately 4:50 p.m. The earlier sunset can be jarring, but for some the extra morning light can offset the effects of darker evenings.
“In the fall, we regain an hour and benefit from more morning light,” Robillard said. “There are fewer negative impacts on sleep, mood, and well-being with this shift, but ultimately it only corrects the artificial mismatch created in the spring.”
Research shows that morning light boosts energy, improves mood, strengthens the biological clock, and promotes better sleep. “Evening light has the opposite effect,” Robillard said.
How does Ottawa’s Peace Tower clock adjust for daylight saving time?
Each fall, at the end of daylight saving time, a government employee halts the clock’s mechanism for a full hour overnight, keeping it frozen until the hour catches up. In spring, the hour hand is advanced by one hour. To avoid confusion during adjustments, the clock’s chimes are temporarily disconnected, maintaining quiet in the early morning.
When did daylight saving time start in Canada?
Canada adopted daylight saving time in 1918 during the First World War, following a global push to conserve fuel by making better use of daylight. It was reintroduced during the Second World War for similar energy-saving purposes. In the post-war years, provinces and cities followed their own schedules, creating a patchwork of time changes.
In 1966, the federal government passed the Time Act to encourage a more uniform daylight-saving schedule. Since then, most provinces and territories have observed the time change, though regions like most of Saskatchewan, Yukon, and parts of Quebec, British Columbia and Nunavut have chosen to stay on standard time year-round.
Would permanent standard time be healthier?
The Canadian Sleep Research Consortium reports that shifting clocks disrupt immune, circulatory, and metabolic systems, linking the twice-yearly change to higher rates of heart attacks, strokes and accidents, especially among vulnerable groups.
“Well-controlled lab studies show that time changes cause increased heart rate, blood pressure, and inflammation, disrupting metabolism and weakening the immune system,” Robillard said. “Epidemiological studies show links between time changes and heart attacks, strokes, infections, immune-related diseases, digestive issues, and a decline in mental health, especially anxiety and depression.”
Robillard notes a 30-per-cent increase in accidents and injuries, particularly on roads and in workplaces, immediately following time changes. At-risk groups include the elderly, children, people with chronic illnesses, and those on the western edges of time zones, where the sun rises later.
“All of this is avoidable,” Robillard added. “In countries that tried permanent daylight saving time, winter depression rose among teenagers, then declined after returning to standard time.”
Does the switch make financial sense?
Daylight saving was introduced in 1918 to save energy, but with modern lighting savings are minimal. Reports suggest a modest 0.5-per-cent reduction in electricity use, but often increased heating and cooling demands.
One reason Canada continues to follow daylight saving is to stay aligned with New York’s schedule, particularly the New York Stock Exchange’s hours. Without synchronization, businesses could face logistical issues with trading hours, operations, and travel schedules.
However, Robillard points out that regions like parts of Quebec, U.S. states such as Hawaii and Arizona, and countries like Mexico have managed well without daylight saving time, even when out of sync with surrounding areas.
Policymakers should weigh these logistical and financial concerns against the clear public health impacts, Robillard said, suggesting that Canadians’ well-being may carry greater long-term value.
What’s next for daylight saving in Canada?
With growing support from researchers and the public, Quebec’s consultation could sway the future of daylight saving time in Canada. If Quebec joins Ontario in the push to end the time shift, it might be enough to tip the scales and bring about a nationwide shift — one that could leave clocks set to standard time once and for all.
Daylight saving time may end, but with your support, stories that matter don’t have to. Subscribe now to sustain the reporting you rely on.
