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TORONTO -- This Saturday night, most Canadians will be setting their clocks an hour ahead for daylight time. But one expert says the practice of changing the clocks can have negative health impacts and staying on daylight time permanently, as some provinces have proposed, could be even worse for your sleep.

Joseph De Koninck, who is a professor emeritus of psychology at the University of Ottawa, has been studying sleep for almost 50 years.

"Our biological clock, which governs everything that we do, is synchronized with the sun," De Koninck said in a phone interview with CTVNews.ca.

"All the research shows that (changing the clocks) does have a negative impact on functioning. There are more car accidents, more health issues, heart attacks, things like that."

After the clocks change, it can take people a week or two to adjust to their new sleep cycle. But the bigger problem comes from what sleep researchers call "social jet lag," which can be attributed to the fact that the sun sets later in the evening.

"You tend to go to bed later because the light exposure tells your body, 'Oh, it's still daytime,' so you can't sleep," De Koninck said.

Having the sun set late in the evening during the summer delays the bodily functions that promote sleep, such as the decrease in body temperature and the secretion of melatonin.

Going to bed later often leads to less sleep, which De Koninck notes is associated with a whole host of health consequences.

"Sleep is a common denominator for physical and mental health. So, the research shows that there are problems associated with sleep deprivation. For example, there's more obesity because our hormones are not well rejuvenated. There are a host of consequences," he said.

Some governments have investigated staying in daylight time permanently. In 2019, British Columbia passed legislation to permanently stick to daylight time if Washington state, Oregon and California also make the move. A similar bill passed in the Ontario legislature would do the same, contingent on Quebec and New York state also sticking with daylight time.

Saskatchewan uses central standard time year-round, and Yukon moved to year-round daylight time in 2020.

But De Koninck warns that staying on daylight time permanently could be worse than maintaining the status quo. Most people would be left waking up in the dark during the winter, which can cause people to feel moody in the morning.

"For Canada, this means that all major cities would experience sunrises well after 8 a.m. and sometimes after 9 a.m.," said De Koninck.

"The most important synchronizer for our biological clock is light. It's light in the morning that starts us, that says our body, 'This is a daytime now.' So, all of the (body functions), meal digestion… everything is synchronized on the basis of that," De Koninck said.

Russia, another large and northern country like Canada, experimented with permanent daylight time in 2011 before abandoning it in 2014.

Given the massive size of the Eastern Time Zone, staying on permanent daylight time could be particularly bad in Thunder Bay and other areas in Northwestern Ontario, which could see the sun rise as late as 9:45 a.m. in the winter. Calgary and Edmonton, as well as other cities located at higher latitudes, could see sunrises as late as 9:30 a.m.

De Koninck says the ideal solution is to switch to permanent standard time. But if we are going to have daylight time, De Koninck suggests that it should begin later in the year to ensure that there's more morning light for early risers. He also suggests having the clocks change on Friday nights to give people more time over the weekend to adjust.

"The worst thing to do is to go for daylight savings time year-round," said De Koninck.