Scientists explained why all countries are switching to permanent winter time rather than summer time

Scientists from the Canadian Medical Association have found that after abandoning seasonal clock changes, people should live year-round on standard winter time. The results of the study, published in the Canadian Medical Association Journal, show that this schedule best aligns with human biorhythms and helps avoid health problems.

Many countries are currently abandoning the practice of changing clocks in spring and fall. However, governments face a choice: permanently adopt summer or winter time. Permanent summer time makes evenings brighter, which appeals to people as it leaves more opportunities for sports, socializing, and shopping after work. But this solution carries a hidden threat — sunrise shifts an hour later. Because of this, in winter millions of people are forced to wake up and commute to workplaces or schools in complete darkness. Doctors emphasize that morning light is critically important for calibrating our internal clocks, quality sleep, and stable mood.

Its deficiency directly impacts well-being, triggering seasonal depression, which affects 1 to 3% of Canadian residents, while another 15% experience milder autumn-winter flare-ups of apathy. Children and adolescents are at particular risk. During puberty, their natural sleep schedule already shifts to later times, and early school in dark mornings only exacerbates sleep deprivation. Early-shift workers, public transit commuters, and residents of rural areas where street lighting leaves much to be desired will also be affected.

"Our biological clocks need morning light to stay synchronized with the 24-hour day. Permanent summer time shifts that light an hour later precisely when winter mornings are already at their darkest," noted Ralph Mistlberger, a professor of psychology at Simon Fraser University.

International experience has already proven the danger of rushing. In 1974, the United States introduced permanent summer time to save energy during the crisis, but repealed the law in less than a year due to mass protests from parents afraid to send their children to school before sunrise. Russia in 2011 also attempted to live on summer time, but returned to winter time in 2014 after a wave of public discontent. A similar experiment in Chile in 2015 also ended with a return to the previous schedule.