The shift to daylight time on March 12 is a sign of spring – but it also means less shut-eye.
Most people will feel drowsy for a couple of days because they haven't prepared their bodies for the time change, says Andrew Lim, a neurologist who specializes in sleep and chronobiology at the University of Toronto.
Except for in Saskatchewan and parts of British Columbia, which remain on standard time year-round, Canadians will set their clocks an hour ahead on Sunday at 2 a.m.
The feeling of mild jet lag is due to missing an hour's sleep, as well as a disruption in circadian rhythm – the body's internal clock, Lim explains.
The symptoms are normally benign, such as yawning and feeling less alert throughout the day. However, there are significant consequences when a nation loses an hour's sleep.
In a recent study published March 1 in the American Journal of Cardiology, researchers from the University of Michigan report a slight increase in heart attacks on the first day (Sunday) of the spring shift to daylight time. In patients at high risk for a cardiac event, they suggest, minor sleep deprivation resulting from the time change could raise levels of stress hormones and inflammatory chemicals just enough to set off a heart attack.
That's not all. On the first Monday of daylight time, "there seems to be a small bump in traffic accidents," Lim says, adding that studies in numerous jurisdictions have consistently shown the link.
The best way to prevent time-change stress and fatigue-related accidents is to go to bed earlier starting two nights before the switch, he says.
Lim suggests starting the bedtime routine a half-hour earlier on Friday and an additional half-hour on Saturday. "What you're doing is gradually slipping into the new schedule rather than doing it all at once," he says.
For children who normally go to bed at 8 p.m., for example, bath time on Friday might start at 6:45 p.m., followed by bedtime stories, toothbrushing and lights out at 7:30 p.m. On Saturday, the routine would start at 6:15 pm to prepare for a 7 p.m. bedtime the night before the time change.
Even with an earlier bedtime, he says, children and adults are likely to wake up at the same time they normally do. Lim recommends going outside early in the day since exposure to natural light helps shift the body's internal clock.
But he adds, "the most important thing is to get that little bit of extra sleep."