Over the years, sleep scientists have documented many problems with Daylight Saving Time (DST), which requires changing the clocks twice a year. After the time change, the incidence of cardiovascular events and mental disorders increases and the frequency of traffic accidents increases. Our bodies are conditioned by daily light and dark cycles, and even a one-hour shift in the time of sunrise and sunset can disrupt the circadian system. Schools and businesses do not set transition start or end times. Changing the clock on Sunday is to make the passage of time easier, but one day is not enough time to be productive.
After reviewing years of study, a panel of 23 scientists published a paper providing evidence for a constant standard time (Rishi et al. 2020). Both the American Academy of Sleep Medicine and the American Medical Association support standard sleep time. The problem with DST is that it doesn’t align with circadian physiology. Late evening light, along with morning darkness, causes a phase delay in the endogenous system. A chronic relationship with increased risk of obesity, metabolic syndrome, heart disease and depression. The misalignment is worse in western time zones where sunset occurs later in the day.
During the 1973-74 OPEC oil embargo, the U.S. adopted permanent DST, only to repeal it after just one winter because of widespread discontent over having to wake up in the dark to go to work or school. In a post i wrote in 2021 I described the origin of DST when in 1916 the German Empire pushed the clocks forward one hour to save fuel. Britain and France did so a few weeks later and the US two years later in 1918 after joining the war in 1917.
DST was later abolished in 1918 when the war ended. During World War II, the US reinstated DST in 1942 and abandoned it after the war ended in 1945. In 1966, the US established rules allowing states to implement DST in the spring and revert to ST in the fall. The following years led to research on various schemes across the country. Currently, only Arizona and Hawaii maintain the ST year-round, with the rest changing twice a year.
Many states have introduced legislation to choose permanent DST or ST, and on July 14, the US House of Representatives passed a bill requiring permanent DST across the US by a vote of 308-117. The bill allows states to opt out if their legislatures pass laws before the bill passes. However, several senators have said it is unlikely to pass the Senate. Why the Chamber chose to ignore the AASM and AMA recommendations is a mystery, as both organizations consulted with Chamber members.
One of the most difficult aspects of year-round DST is its effect on children who have to wake up and go to school well before sunrise. You can see the effect by looking at the sunrise and sunset times for each day of the year that you live. For example, in Denver, Colorado on October 5, 2026, sunrise is at 7:00 AM. With permanent DST, sunrise would be at 8:00 a.m. and many children would be waiting for buses in the dark. If you have an opinion about whether the US should keep the current DST-ST transition or switch to permanent DST or ST, now is the time to contact your Representative and two of your state senators to express your views.
