Your DNA has a schedule. Daylight Saving Time doesn't care.

Our body’s natural clock — the circadian rhythm — gets disrupted when Daylight Saving Time hits. (Photo by Adobe Stock/University of Windsor)

Nearly half your genome operates on a clock. Daylight Saving Time throws it off.

When the clocks move forward an hour for Daylight Saving Time on March 8, our body’s natural clock — the circadian rhythm — gets disrupted. 

This year, British Columbia will move the clocks forward for the last time as they make Daylight Saving Time permanent — a move Dr. Phil Karpowicz says could help reduce annual disruption.

Karpowicz, UWindsor circadian rhythm researcher and biomedical science professor, says we cannot discount the toll this takes on our overall health.

“Daylight Saving Time is overall unhealthy, but it is deeper than just the time change that happens that one day,” says Karpowicz.

“For most people you are staying up later and waking up when it is still dark, because of Daylight Saving Time, your body ends up out of sync from your environment for half the year.”

He says we will see acute issues pop up, such as the rise of traffic accidents on the Sunday and following Monday. But our general health is also affected.

“Every cell in your body is affected so it is a major part of your basic physiology,” he says.

“Just under half your genome is under circadian control so you’re turning thousands of genes on and off depending on the time of day. If due to Daylight Saving Time you’re not ready to wake up and you have to wake up earlier, you’re going to be really tired because you are imposing a form of jet lag.”

But sleep is only part of the picture.

Karpowicz and his research team study how the biology of the digestive tract is controlled by the circadian rhythm and what that has to do with when we eat.

Dr. Phil Karpowicz and his research team study how the biology of the digestive tract is controlled by the circadian rhythm. (NAOMI PELKEY/University of Windsor)

“We have cells in our body responding to nutrients from food. We also have a microbiome population in our intestine, and those bacteria are very sensitive to nutrition so when we eat food they start to grow and make all kinds of chemicals that affect different parts of the body. It has to do with the time that we eat,” says Karpowicz.

“It is best not to ignore our circadian rhythm because experiments on laboratory animals have shown that eating regularly means they live 30 per cent longer. Clinical studies have shown eating regularly promotes health in humans as well.”

People who travel a lot, he adds, or who do shift work have negative health outcomes because of how often they disrupt their circadian rhythm.  

For Daylight Saving Time, Karpowicz says it arbitrarily interrupts our natural clock in the same way time zones do not reflect proper respect to the circadian rhythm.

“It isn’t just about a time change — it is about the fact that where you are geographically makes a huge difference and there are wild examples when you look at time zones,” he says.

“For example, just in Canada Eastern Time is a time zone that spans from western Ontario all the way over to Labrador – but the sunrise and sunset in those parts of Canada are at totally different times. Daylight Saving Time is in general decoupled from our natural rhythms in the spring and fall. Overall Standard Time is known to be best year round, because Daylight Saving Time means you have to wake up when it’s dark and won’t go to bed appropriately because it’s still light out.”

He points out you cannot fight the change because you still need to get up and go to work and get the kids to school. But he says some people will adjust differently than others.

“There are different chronotypes — we call them early birds and night owls,” he says.

“People have a clock in their body that tells them day and night but the way they synchronize the clock to their environment dictates when they wake up and when they want to sleep.”

His only advice is to keep consistent in your habits.

“There is a regularity to your body and if you respect that it will keep you healthy. Keeping a good sleep-wake cycle and a good feeding-fasting cycle is best,” says Karpowicz.

“Ultimately there’s not much we can do about Daylight Saving Time — hopefully they’ll get rid of it.”

By Sara Elliott

Courtesy: https://www.uwindsor.ca/news/2026-03-04/your-dna-has-schedule-daylight-saving-time-doesnt-care