B.C. is adopting permanent daylight time. Sleep researchers say standard time is healthier

Scientists who study sleep are warning B.C.'s decision to adopt permanent daylight time could have a negative impact on overall health, especially for children.

"Scientists over the world have been warning about the negative health and safety implications of permanent daylight saving time and have been advocating for permanent standard time instead," said Myriam Juda, an adjunct professor and sleep researcher at Simon Fraser University.

The change means B.C. will transition onto daylight time this weekend and never change the clocks again.

Among the critics is Jamie Zeitzer, a professor in Stanford University's department of psychiatry and behavioral sciences, whose research was cited by the B.C. government in its news release announcing the change. 

Zeitzer says it was "kind of weird" to see his work used that way.

"It's scientifically not a good idea, and in terms of health, I don't think it's a good idea to do that kind of switch," he said. 

Standard time means the sun is at its zenith around noon, with daylight more evenly split between morning and afternoon. Daylight saving time shifts the clock ahead by an hour, meaning less light in the morning and more in the afternoon.

Juda said that change can disrupt our circadian clock, which regulates sleep-wake cycles.

"This circadian clock synchronizes to the light-dark cycle of the sun through specialized photoreceptors in the eye. And morning light exposure is really important here," she said.

Morning light helps set the timing of melatonin release later in the day. Without it, people may feel more alert at night and more fatigued during the day, Juda said. She added that teenagers are particularly affected because their sleep patterns already tend to shift later.

Sleep is also critical for children's brain development, she said.

Communities on the western edge of a time zone, such as Vancouver and Victoria, are especially affected by dark winter mornings under permanent daylight time. In midwinter, the shift would push sunrise past 9 a.m. in both cities.

"That means that most children will walk to school in the dark. Most office workers will commute in the dark and also will not get an opportunity for any morning light exposure," Juda said.

She estimates most British Columbians would lose, on average, just under half an hour of sleep each night after the change.