American observers with binoculars, a clipboard, and a golden retriever watch Canadians go about their day in a waterfront town.

Before We Change the Clocks Forever, Let’s Watch Canada

ByKaty Morter, DC

What America’s 1974 experiment—and Canada’s new daylight saving policies—could teach us about heart health, depression, prescription medications, and the biological clock.

Here we go again. Daylight saving time is back in the national conversation, and once again, we’re debating whether we should stop changing our clocks twice a year.

President Trump wants permanent daylight saving time. The House passed the Sunshine Protection Act in July, but the legislation has stalled in the Senate. Even Republicans disagree about what should happen next, including Arkansas Senator Tom Cotton, who has raised concerns about children heading to school in the dark.

I understand both sides. Nobody enjoys losing an hour of sleep in the spring, and having more daylight in the evening sounds wonderful. But there’s something missing from this conversation: what does changing the timing of daylight actually do to our bodies and brains?

And here’s an interesting thought. Rather than rushing into a permanent decision, why don’t we watch what happens in Canada?

We’ve Tried This Before

In January 1974, the United States began an experiment with year-round daylight saving time. We were in the middle of an energy crisis, and the idea was that shifting daylight into the evening would conserve electricity.

Unfortunately, things didn’t go quite as planned.

Parents worried about children traveling to school in the dark, and winter mornings became a major point of controversy. By October, Congress had changed course, restoring standard time for the following winter. Subsequent evaluations also questioned whether the anticipated energy savings and safety benefits were as substantial as initially suggested.

But here’s what interests me most: what about the health effects?

In 1974, our understanding of circadian rhythms, seasonal depression, and the neurological effects of light exposure was nowhere near what it is today. Seasonal affective disorder wouldn’t even be formally described until the 1980s.

We were measuring electricity consumption and traffic accidents, but we weren’t adequately studying what these changes might be doing to people’s mental health.

That doesn’t mean depression increased. It means we don’t have the evidence to know.

What Happens When We Change the Clocks?

We actually have some interesting research on both the spring and fall transitions.

In the spring, when we move our clocks forward and lose an hour of sleep, researchers have observed short-term increases in certain cardiovascular events. One Michigan study found a 24% increase in heart attacks on the Monday following the spring transition. A broader 2024 analysis found a more modest increase of approximately 4%.

Other research has identified temporary increases in stroke risk and fatal traffic accidents around clock changes. Not every study has confirmed these findings, however, and a large 2025 study found no statistically significant increase in heart attacks during either transition week.

Then there’s the fall transition.

A Danish study found an approximately 11% increase in hospital-diagnosed depressive episodes following the autumn clock change. Researchers suggested that the sudden loss of evening daylight might contribute to the increase.

These studies don’t prove that changing the clocks directly causes heart attacks or depression, but they raise questions we shouldn’t dismiss.

Our bodies operate on circadian rhythms that regulate far more than sleep. Light entering our eyes communicates with the brain’s central biological clock, located in the hypothalamus. This system helps coordinate cortisol, melatonin, blood pressure, metabolism, alertness, and emotional regulation.

Morning light is particularly important because it helps synchronize our internal clock with the outside world.

And that’s where the distinction becomes important: eliminating clock changes and adopting permanent daylight saving time are not the same decision.

Permanent standard time also eliminates the twice-yearly disruption, but it provides earlier winter sunrises. Many sleep and circadian researchers favor that arrangement because of the importance of morning light.

What About Depression and Medication Use?

Here’s another question I think deserves attention.

If changes in daylight exposure affect sleep, mood, and emotional regulation, could they also influence antidepressant and sleep medication prescriptions?

We already know that seasonal changes in daylight can affect depression, particularly in people with seasonal affective disorder. Research has also identified seasonal patterns in antidepressant prescribing.

So what happens when an entire population begins experiencing later winter sunrises?

Would we see more depression? More prescriptions for antidepressants or sleep medications? Or might eliminating the twice-yearly disruption actually improve mental health?

We don’t know.

And while pharmaceutical companies have a financial interest in medication sales, that doesn’t establish that they’re influencing daylight saving policies. It’s also important to remember that an increase in prescriptions doesn’t necessarily mean an increase in depression. Greater awareness and better access to treatment can influence prescribing rates.

Still, if we’re going to make a decision affecting the biological rhythms of millions of people, shouldn’t we measure whether it changes their need for medical treatment?

Canada Is Giving Us an Opportunity

This is where things get interesting.

In 2026, British Columbia adopted permanent daylight saving time, and Alberta and Manitoba have also decided to eliminate seasonal clock changes.

That gives researchers an unusual opportunity to study what happens when populations live through winter without returning to standard time.

Rather than immediately following their example, what if the United States spent the next few years observing the results?

We could examine depression diagnoses, antidepressant and sleep medication prescriptions, cardiovascular events, sleep quality, workplace productivity, energy consumption, and traffic safety. We could also look at school attendance, children’s sleep patterns, and the safety of traveling to school during darker winter mornings.

Suicide rates deserve careful examination, too, although meaningful conclusions would require multiple years of data and consideration of many other contributing factors.

Ideally, researchers would compare Canadian regions with different time policies while accounting for latitude, economic conditions, healthcare access, and other differences.

It wouldn’t be a perfect experiment. But it could provide valuable evidence about both the benefits and unintended consequences of permanent daylight saving time.

Perhaps we’d discover that the benefits outweigh the risks. Perhaps we’d find that permanent standard time is healthier. Or perhaps the most important benefit comes simply from eliminating the twice-yearly transitions.

Wouldn’t it be useful to know?

Maybe We Don’t Need to Be First

The United States tried year-round daylight saving time in 1974, when we understood far less about the relationship between sunlight, circadian rhythms, and human health.

Today, we have better research, better medical data, and a much greater awareness of mental health.

We also have an opportunity to observe what happens in Canada before making a permanent nationwide decision.

This doesn’t have to be another political argument. We can recognize the inconvenience of changing clocks while still asking whether permanent daylight saving time is the healthiest alternative.

And really, why are we spending so much energy arguing among ourselves when we have an opportunity to sit back, watch what happens in Canada, and learn from their experience? We could potentially reap the benefits of what works while avoiding some of the unintended consequences. That seems like a pretty sensible approach to me.

After all, sometimes the smartest decision isn’t to be the first to make a change.

It’s to be the one who pays attention to what happens afterward.

Research and Further Reading

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