Pair of Manitoba cardiovascular researchers call for an end to daylight time

As most North Americans get ready to move their clocks forward to daylight time this weekend, two researchers from Manitoba are calling for an end to the practice.

Dr. Lorrie Kirshenbaum and Dr. Inna Rabinovich-Nikitin work at the Institute of Cardiovascular Sciences at St. Boniface Hospital, where their labs study the link between circadian rhythm — the body's biological clock — and cardiovascular health.

Both are also members of the Canadian Society of Chronobiology, which advocates for the elimination of the twice-yearly time changes.

In a news release Thursday, Rabinovich-Nikitin said their research has found the circadian clock regulates a crucial adaptive stress response which affects the heart's "quality control mechanisms," as well as the survival of cells 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," she said.

In an interview with CBC, Kirshenbaum described the body's attempts to keep up with the clock as social jet lag. 

"We're getting more darkness in the morning and we're getting more light in the evening. And so that's what messes up the clock," he explained. "Our body is trying to align to it and it doesn't."

The doctors note that shift workers may be more vulnerable to the negative impacts of time change.

"Daylight saving time can make it difficult for shift workers to adjust their internal clocks to their work schedule, leading to sleep deprivation, fatigue, and decreased cognitive function," the release said. 

Kirshenbaum says the impacts of the time switch can be seen in things such as mild depression and blood pressure changes.

"When we sleep our blood pressure goes down and in the morning it comes up. Our heart rates change the same way," he said. "Even the one-hour time change will affect the physiology and our bodies."

Switching permanently to standard time would help prevent increased risks of diabetes, heart disease and depression that the studies associate with daylight saving, the release said. 

Sleep expert Diana McMillan, an associate professor at the University of Manitoba and a registered nurse with a PhD in nursing science, agrees that standard time is better for the human body but says the switch to daylight time can be used as an opportunity to re-evaluate sleep patterns. 

Our sleep does a lot for us and it's important to "see how we can support better sleep in our families and for ourselves, not only during the daylight saving shift, but on a daily basis," she told CBC on Thursday.  

Creating a bedtime routine and minimizing caffeine and alcohol intake are ways to get better sleep at night, McMillan said.

Going to bed 15 minutes earlier each night in the days leading up to the time change can also help prepare for the lost hour, she said. 

Daylight time begins on Sunday, March 12.