It’s that time of year again, when most Canadians move our clocks ahead one hour to mark the start of daylight time.

Clocks officially move ahead one hour at 2 a.m. on Sunday across Canada, with the biggest exception being most of Saskatchewan, where clocks remain on Central Standard Time all year.

That means Canadians in most of the country will lose an hour of sleep on Saturday night. But looking on the bright side, there is more daylight in the evening hours.

It’s been well-documented that the time changes in the fall and spring can feel like they’re taking a physical toll.

But does adjusting the time really affect our internal body clock?

“It is a real thing,” Dr. Harneet Walia, a specialist at the Sleep Disorders Center in Cleveland, told CTV News Channel on Friday. “Our sleep-wake schedule is determined by an internal body clock, as well as the external clock.”

Walia said that when we transition to daylight time, “our internal clock has to adjust to that, and can take some time to adjust to that and that’s why we face those consequences that we face.”

Losing the hour of sleep can lead to an increased risk of drowsy driving, heart attacks, changes in mood, irritability and impaired concentration.

The adverse effects we experience from the loss of one hour’s sleep is similar to what travellers experience with jetlag, says Colleen Carney, director of the Sleep and Depression Lab at Ryerson University in Toronto.

“One hour is the minimal threshold that tricks the body clock into thinking it’s supposed to be one time but it’s actually another,” Carney said on CTV News Channel. “Whenever you have that situation it’s like travelling through one time zone, so you get jetlag symptoms.”

She added: “Jetlag isn’t really about the travel, it’s about the mismatch between the clock and the body, and the cues in the environment that are telling it what time it is.

“So what’s going to happen this weekend is there is going to be some discrepant cues.”

Walia said the time change is more of a problem for those who are chronically sleep-deprived, but the time it takes to recover from the sleep loss depends on the individual.

“For some people, it can take a day, for some people it can take a few days,” Walia said.

So what can people do ahead of time to prepare for daylight time?

“We tell patients to start easing into this daylight saving time a few days prior to when it happens,” Walia said.

Starting a few days before, people should begin going to bed earlier “in small increments” of 15 minutes.

Maintaining good sleep hygiene is “most important,” Walia said, and that includes ensuring you’re making sleep a priority and getting a good 7-8 hours of non-interrupted shuteye each night.

Other daylight time management tips:

  • Limit exposure to screens before bed, including television, computers and cellphones
  • Expose yourself to bright light in the morning
  • Avoid caffeine three to four hours before bed
  • Engage in a moderate amount of exercise