As Ontarians Adjust To Daylight Saving Time, Doctors Warn Of Health Impacts

Groggy Ontarians were again forced to adjust their eyes when millions woke up on Sunday morning as Daylight Saving Time began and clocks sprang forward. But is it that simple?

Doctors in the U.S. are speaking out on the yearly time change, which, in Canada, starts on March 12, 2023, and will end on Nov. 5, 2023, noting that Daylight Saving Time has been linked to an increase in cardiac events.

A 2020 study revealed what scientists called “detrimental health effects,” including the incidence of acute myocardial infarction (MI) and increased ischemic stroke following both spring time transitions. It was mentioned that conditions affecting sleep are known to provoke atrial fibrillation (AF), yet, the effect of Daylight Saving Time transitions on AF “is unknown.”

Sleep specialists and health experts point to a relatively simple issue: while Daylight Saving Time increases exposure to light, it can make it harder for people to get to sleep, thus leading to an array of issues. The American Academy for Sleep Medicine (AASM) recently touched on the yearly time switch, linking the transition from standard time to Daylight Saving Time to an upsurge in cardiovascular events, mood disorders, and car crashes.

More recently, the AASM and the American Medical Association both remarked that switching to standard time is preferred, bringing us to Canada. Ontario passed a bill back in 2020 to stay on Daylight Saving Time permanently, but it’s been largely crickets on it since.

Last year, the U.S. Senate voted unanimously to stick with Daylight Saving Time permanently, but that bill stalled in the House of Representatives. Last week, however, a group of bipartisan Senators reintroduced the legislation. If it gets through both the Senate and the House, this weekend’s time change would be the final one in the United States — potentially paving the way for Canadian provinces to follow suit.

Those favouring a permanent move to Daylight Saving Time say it will lead to fewer car crashes, less energy use and improved health. Those against it say the mornings would be too dark during December and January. Around and around we go.

Yukon and most of Saskatchewan keep their clocks the same year-round. Yukon made the switch for the last time in March 2020, and standard time is now permanent there.