British Columbia votes to stop switching clocks. Scientists worry.

British Columbia will flip its clocks one last time this weekend. Starting next year, the province stays on daylight saving time permanently — a move backed by over 90% of residents who want that extra hour of evening sunlight year-round, even in winter's darkest months.

It feels intuitive. More daylight at the end of the day sounds better for how we actually live now. Premier David Eby put it simply: "The way that we live our lives now in the modern era, having an extra hour of sunlight at the end of the day, whether it's the winter or the summer, makes a big difference for people."

But the medical evidence tells a different story — one that reveals the gap between what feels right and what our bodies actually need.

What our circadian clocks actually want

Our internal timing systems didn't evolve for modern schedules. They evolved for the sun. When light hits your eyes in the morning, your brain gets a signal to wake up and prepare your body for the day ahead. When it stays bright into the evening, your brain struggles to trigger sleep. Permanent daylight saving time locks us into a permanent mismatch: dark mornings when we need light, bright evenings when we need darkness.

Emily Manoogian, a circadian biologist at UC San Diego's Salk Institute, explains the ripple effect: "When you're not getting light in the morning, your body thinks it's not morning yet. And it's very hard to just force your body to wake up without that light." That misalignment cascades through the day — affecting focus, metabolism, and sleep quality the next night.

The health costs are measurable. A Stanford study published in September 2025 found that switching clocks twice yearly drives up strokes and obesity cases significantly. But here's the surprising part: permanent daylight saving time is better than the current system, yet worse than permanent standard time. If British Columbia had chosen permanent standard time instead, researchers estimate 300,000 fewer strokes and 2 million fewer obesity cases annually across a similar population.

"Every medical and scientific society would argue we should never go to daylight saving time," Manoogian said. The energy savings that originally justified the practice? They don't materialize. Modern evidence shows daylight saving doesn't reduce energy use.

Eby acknowledged the health concerns but noted that British Columbians already endure dark winter mornings — the province sits on the western edge of its time zone. "People really want that hour at the end of the day," he said. It's a choice between two imperfect options: dark mornings now, or dark mornings plus the circadian disruption of permanent misalignment.

What this means for sleep and health

The stakes extend beyond grogginess. Misaligned circadian rhythms increase risk for heart attacks and strokes in the weeks following time changes. Over months and years, chronic misalignment raises the risk of cardiometabolic disease, depression, and even cancer. "When we can realign better to our environment, we get better sleep," Manoogian said. "We have lower risks of almost any chronic disease you can imagine."

If you live in a region making this shift, small adjustments can soften the blow: get as much morning light as possible (turn on every light in your home if the sun hasn't risen), maintain consistent sleep and meal times, and if you have kids, shift their schedule gradually — about 20 minutes per day over three days — rather than all at once.

British Columbia's decision reflects a real tension in modern life: our preferences don't always align with our biology. The province chose what feels better in the moment. Whether that trade-off was worth it will likely become clearer in the health data over the next few years.