A 2008 Swedish study found a higher incidence of heart attacks in the first three workdays after the clocks 'spring forward.'
Researchers chalked it up to a lack of sleep, and did find a similar decrease in the number of heart attacks when clocks 'fall back' later in the year.
There's also a theory about drivers and pedestrians who have lost an hour of sleep creating a potentially-dangerous combination of sleepy people behind the wheel and those on foot being not as sharp as they might normally be.
However, Dr. John Vavrik, a psychologist with the Insurance Corporation of British Columbia, says that daylight saving time doesn't appear to be as big a factor in crashes as it used to be.
"The good news is that we're seeing less and less of an impact of the DST change. Maybe people are getting the message, or maybe we're just sleep-deprived all the time and so the DST doesn't seem to be making a huge difference anymore."
The time change can also create confusion between provinces that do adopt the convention, and those that don't. People in Saskatchewan stay on standard time year-round.
Some say the best advice for reducing time-shift fatigue overnight is to exercise, lay off the caffeine before bed, go to bed at a regular time and put down the smartphone.
Another good piece of advice? Set the clocks ahead on Saturday night.