How to adjust to daylight saving time

The best way you can prepare for the twice-yearly clock change is to try to adjust your sleep schedule gradually in the days leading up to the change, according to an Athabasca University (AU) researcher who studies sleep health.

But even if you haven’t been slowly shifting your sleep schedule ahead of time, there are things you can do to minimize the negative impact of the time change, says Dr. Steven Johnson, an associate professor and dean of AU’s Faculty of Health Disciplines.

“Avoid overconsumption, whether alcohol or food. Don’t stay up late or don’t sleep in too late,” he said. “Routine is key, and that shouldn’t be different from any other weekend.”

Where it’s possible, adjusting your bedtime and wake-up time by 15 minutes in each of the four or five days ahead of the time change is recommended.

Impact of sleep on health

Johnson’s research has historically focused more on physical activity and healthy eating, but more recently he has been looking at sleep as a health behaviour that can influence other aspects of health—particularly in the context of Type 2 diabetes.

But regardless of the specific context, he said there’s a large body of research showing that getting less sleep, whether in terms of quantity and quality, can have significant impacts on individuals.

“Most often people will say a good sleep is, I got seven to nine hours of sleep last night,” he said. “But in those seven to nine hours, what was the quality of your sleep? We have to look at both aspects of that.”

These effects tend to become more pronounced when we change the clocks to move to and from daylight saving time—the “fall back” in which clocks get set back one hour, and the “spring forward” in which clocks are moved ahead one hour.

Johnson said looking at aggregate data of the days following the “spring forward” time change—meaning at the population level rather than for a specific individual—there is an increased likelihood of cardiovascular incidents like heart attacks and stroke, an increase in motor vehicle collisions, a decrease in work-related output, and an increase in work-related injuries.

This happens because of our circadian rhythms, also called internal clocks, that are typically set by exposure to light hours rather than the number on the clock and our daily activities.

Resetting our circadian rhythm

Ultimately, changing the clock requires us to reset our circadian rhythm with more light exposure in the morning but this is difficult with the daylight saving—and so a good strategy is to get light exposure in the morning as soon as possible.

There is often debate about the benefits of the twice-yearly time change, with some jurisdictions choosing not to change the clocks.

While Johnson acknowledged he’s no expert on the economic reasons for changing the clock and didn’t want to weigh in on that aspect, he said from the perspective of individual health there may be benefits to discontinuing the practice.

“My perspective is that the change is not worthwhile from a physiological standpoint,” he said. “It’s disrupting our physiology to do that, and so that has a greater impact on our health.”

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