Why Sleep Scientists Oppose Daylight Saving Time
For years, sleep scientists have documented many problems with Daylight Saving Time (DST), which requires changing clocks twice a year. After time changes, incidences of adverse cardiovascular events and mood disorders increase, and the frequency of vehicular crashes rises. Even the one-hour shift in timing of sunrise and sunset can disrupt the circadian system.
Scientific Evidence for Permanent Standard Time
After reviewing years of study, a panel of 23 scientists published a paper laying out the evidence for permanent standard time. Both the American Academy of Sleep Medicine and the American Medical Association favor permanent standard time. The problem with DST is that it is inconsistent with circadian physiology. Late evening light, along with early morning darkness, causes a phase delay in the endogenous system. Chronic misalignment has been associated with increased risk of obesity, metabolic syndrome, heart disease, and diabetes.
Historical Lessons and Current Legislation
During the OPEC oil embargo of 1973-74, the U.S. enacted permanent DST and then dropped it after only one winter because of widespread dissatisfaction, primarily due to having to wake up in darkness to get to work or school. On July 14, 2026, the U.S. House of Representatives passed a bill to require permanent DST throughout the U.S. with a vote of 308-117, but several senators have said it will likely not pass in the Senate. Scientists and physicians are puzzled why the House ignored the recommendations of professional medical organizations.
Special Impact on Children's Health
One of the most problematic aspects of year-round DST is its effect on children having to wake and go to school long before sunrise. For example, in Denver, Colorado, on October 5, 2026, sunrise is at 7:00 AM. With permanent DST, sunrise would be at 8:00 AM, with many children waiting for buses in the dark, increasing safety risks.
If you have an opinion about whether the U.S. should keep the current DST-ST switch or change to permanent DST or ST, now is the time to contact your Representative and your two state senators to convey your views. The Xiaoshu Health App can sync with Apple Health to track related indicators such as sleep and heart rate.