As daylight saving time approaches across much of the United States and Canada, most people will move their clocks forward an hour at 2:00 a.m. local time — sacrificing an hour of morning sunlight for more daylight in the evening. When the period ends later in the year, clocks are set back to return more light to the morning during the darkest months.
British Columbia, however, has decided this will be the last time it shifts clocks seasonally. The province plans to keep daylight saving time year-round after a measure backed by what Premier David Eby described as “more than 90% of British Columbians.” Eby told NPR that, given modern lifestyles, people value “having an extra hour of sunlight at the end of the day, whether it’s the winter or the summer.”
Many sleep and public-health experts caution against permanent daylight saving time. Emily Manoogian, a senior staff scientist at the Salk Institute and an executive member of the Center for Circadian Biology at UC San Diego, warned that making daylight saving permanent carries health risks. She noted that the U.S. once tried permanent daylight saving in the 1970s for a year but reversed the policy after dark winter mornings led to children walking to school in darkness and a rise in fatal traffic incidents.
Eby acknowledged concerns about health effects but said B.C. residents are accustomed to dark winter mornings because the province sits on the western edge of its time zone. “People really want that hour at the end of the day,” he said.
Why experts worry
Scientists argue that permanent standard time better matches human biology. Our internal circadian clocks, which regulate sleep–wake cycles and many cardiac and metabolic functions, are synchronized by light. Morning sunlight hitting the eyes is the strongest cue to signal the brain and body to wake and prepare for the day; without it, waking is harder.
Conversely, bright evenings delay the onset of sleep. When evenings stay light later, people tend to go to bed later and struggle to wake the next morning, producing later sleep schedules, reduced morning alertness, and impaired daytime cognition and metabolism. Those shifts have been tied to short-term rises in car accidents, heart attacks and strokes in the weeks after clocks advance for daylight saving time.
“We know that sleeping, eating, getting light at the wrong time is a huge risk for cardiometabolic disease,” Manoogian said. She also noted that daylight saving time was originally intended to save energy, but evidence shows it does not accomplish that goal.
Recent research has reinforced these concerns. A study published in the Proceedings of the National Academy of Sciences in September 2025 reported that switching clocks twice a year carries a measurable public-health toll, increasing rates of stroke and obesity. The authors concluded that permanently adopting standard time would yield the largest health benefits, while permanent daylight saving would reduce some harms but not as much as staying on standard time.
Aligning schedules more closely with natural light, Manoogian said, improves sleep and lowers risks for many chronic conditions — from cardiometabolic disease to cancer and mood disorders such as depression or bipolar disorder.
How to reduce the impact of time changes
If you’re worried about daylight saving’s effects, experts recommend practical steps:
– Seek morning light: Get outside in daylight soon after waking when possible. If it’s still dark, use bright indoor lighting to mimic morning light.
– Protect your sleep: Aim for 7–9 hours of sleep per night and keep a consistent sleep schedule even on weekends.
– Regularize meals: Eat on a steady daily schedule aligned with your wake hours. Delaying the first meal by an hour or two after waking and restricting eating to an 8–10 hour window can help metabolic health.
– Adjust children gradually: Shift bedtime and wake time in small increments (about 20 minutes per day) over several days to ease transitions.
Whether British Columbia’s move will prove popular or costly for public health remains to be seen. For now, residents and policymakers face a trade-off between more evening daylight and the biological benefits of morning light — and experts say aligning our clocks with natural light patterns matters for long-term health.