Two Winnipeg doctors say the exhaustion soon to come when Manitobans set their clocks ahead one hour Sunday could have serious long-term health consequences — and it’s time to abolish the practice.

Dr. Lorrie Kirshenbaum and Dr. Inna Rabinovich-Nikitin are cardiovascular researchers with St. Boniface Hospital, U of M professors and Manitoba’s two members of the Canadian Society of Chronobiology, which advocates for a switch to a permanent standard time to replace the age-old “spring forward, fall back” clock shift.

New research from the pair finds the changes are detrimental to cardiovascular health, and can be directly linked to increased risk of heart disease and heart attacks.

“One of the interests we had, where we started from, was understanding how changes in the body’s internal clock — or circadian rhythm — when that becomes disrupted, affects cardiovascular disease,” Kirshenbaum, the director of St. Boniface Hospital Research Centre’s Institute of Cardiovascular Sciences, said Thursday.

“It also affects other diseases, most notably obesity, cancer, high blood pressure… mental disorders.”

Their findings show the body’s internal clock regulates a “crucial adaptive stress response” that affects the heart’s ability to maintain quality control and help cells survive after a heart attack.

“So, maintaining a healthy circadian clock is important not only for disease prevention, but also affects the outcomes following heart attack,” Rabinovich-Nikitin, the principal investigator of women’s heart health and cardiometabolic function at St. Boniface Hospital Research Centre, said in a statement.

Their research is currently being reviewed for publication.

Prior studies have found similarly concerning statistics, including increases in fatal car collisions, strokes and heart attacks in the days following the switch.

“The change in standard time to Daylight Savings Time basically, shifts the amount of sleep we get and, by doing that, it affects our ability to function and ultimately leads to disease,” Kirshenbaum said.

Circadian rhythm is determined by the sun; when the the brain senses the morning light — even during sleep — it sets off a signal to the retinas, which travels to the brain’s circadian “clock.” The result is that the twice-yearly time change disrupts that rhythm, messing with the signal to wake up.

“It’s well-documented, if you interfere with the length of the light cycle or length of the dark cycle — in other words, shortening or lengthening — it affects this inherent biology,” Kirshenbaum said.

“In other words, the clock on the wall does not match properly with our biological clock.”

Canada introduced daylight time in 1918 in an effort to increase production during the First World War. When the fighting ended, so did the time change, but it returned during the Second World War and has remained a fixture in many parts of the country since.

Yukon, most areas in Saskatchewan and some parts of B.C., Ontario, Quebec and Nunavut do not participate in the time change. Calls to drop the practice elsewhere in the country and in the United States have increased during recent years.

Alberta held a referendum on the idea in 2021, and the results were nearly 50-50.

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Last November, then-municipal relations minister Eileen Clarke introduced a bill in the legislature that would end daylight time in Manitoba — but would be contingent on the U.S. doing the same — with the intention of staying in sync with trading partners south of the border.

At the time, Clarke, who is now Minister of Indigenous Reconciliation and Northern Relations, said the province would begin consultations with Manitobans early this year. A spokesperson from the province said more information on consultations would be shared in the semi-annual time-change bulletin, scheduled for release Friday.

The public underestimates just how helpful a steady circadian rhythm can be, and just how harmful it can be to disrupt it, Kirshenbaum said.

“People don’t recognize that even a simple time change of an hour can make a difference,” he said.

malak.abas@winnipegfreepress.com

Malak Abas
Reporter

Malak Abas is a reporter for the Winnipeg Free Press.

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