Shining light on permanent daylight saving time and health

“British Columbia is going to change our clocks just one more time—and then never again.” Premier David Eby delivered this announcement on 2 March 2026, just ahead of the annual springing forward of the clocks, which had been implemented in British Columbia for decades.[1] And indeed, early on the morning of 8 March 2026, BC timekeeping permanently moved from Pacific Standard Time to Pacific Daylight Time.

What does this mean for our health? Evidence shows that twice-yearly time changes can disrupt sleep.[2] This is hardly surprising to anyone who has struggled to get up in the morning the day after springing forward each year. Lost sleep due to time changes in the spring has been linked in some research to increased rates of motor vehicle crashes, while impacts on mental health have been observed following time changes in both spring and fall.[3] Premier Eby’s announcement asked that we think of the children, observing that “every parent knows that changing clocks twice a year causes a significant amount of chaos on already busy lives.”[4]

Researchers studying the issue largely agree that a policy to eliminate time changes is a good move from a health perspective. But why a move to permanent daylight saving time, rather than permanent standard time? After all, standard time, as the name suggests, is the default. For the most part, under standard time, we see the sun at its highest point at noon, keeping midday aligned with its intuitive noontime correlate. The popularity of daylight saving time is linked, in large part, to there being additional daylight hours in the evening during the affected months—an extra hour for outdoor sports and recreation, time spent in parks, and safer outdoor play for children. It is easy to see the appeal of an extra hour of evening daylight during the winter.

But wait—stop the clock. Just hours after the announcement of permanent daylight saving time in BC, news coverage began to explore the dark side of this policy. Annoyingly enough, that extra hour of daylight in the evening comes with an extra hour of darkness in the morning.[5] Under permanent daylight saving time in Vancouver, for example, sunrise will come after 8 a.m. for almost 4 months of the winter and later than 9 a.m. for about 1 month. The effect will be even more pronounced in communities farther north. This will mean a lot of dark mornings for BC residents.

Sleep experts have described health harms that may arise as permanent daylight saving time decouples the timing of waking from the sunrise. Our circadian rhythms rely heavily on exposure to morning light to start our days,[2] and disruptions to sleep patterns and related impacts on concentration and mood are important impacts. Many experts suggest that the healthy way to eliminate twice-yearly time changes would be permanent standard time rather than permanent daylight saving time.[5]

It is challenging to quantify the health benefits of an added hour of sun on a beach, baseball field, or balcony, let alone to tally up the apples and oranges of social and recreational gains versus circadian rhythm disruptions. Reaching public-health consensus on these options, let alone general public consensus, may be as hard as reaching consensus on a preference for sunrises or sunsets. Where we do have strong agreement is that an end to changing our clocks will be welcome and positive for health. As a society, we should anticipate, study, and mitigate specific harms and make the most of that extra daylight.
—Michael Schwandt, MD, MPH, FRCPC

References

1.    Cecco L. Time for a change: British Columbia decides to keep daylight saving time permanently. The Guardian. 8 March 2026. Accessed 15 March 2026. www.theguardian.com/world/2026/mar/08/british-columbia-canada-daylight-saving-time.

2.    Rishi MA, Ahmed O, Barrantes Perez JH, et al. Daylight saving time: An American Academy of Sleep Medicine position statement. J Clin Sleep Med 2020;16:1781-1784. https://doi.org/10.5664/jcsm.8780.

3.    Steponenaite A, Wallraff JP, Wild U, et al. A systematic review of epidemiological studies into daylight-saving time and health identifying beneficial and adverse effects. Eur J Epidemiol 2026. https://doi.org/10.1007/s10654-026-01372-8.

4.    British Columbia Ministry of Attorney General. Adopting permanent daylight saving time: ‘Spring forward’ on March 8 will be the last time change, ending twice-yearly clock changes [news release]. 2 March 2026. Accessed 15 March 2026. https://news.gov.bc.ca/releases/2026AG0013-000209.

5.    Carman T. ‘Scientifically not a good idea,’ says researcher whose work informed B.C.’s daylight-time decision. CBC News. 5 March 2026. Accessed 15 March 2026. www.cbc.ca/news/canada/bc-daylight-saving-health-concerns-9.7114947.