“The light/dark cycle is key in circadian entrainment. The acute alterations in timing due to transitions to and from [Daylight Saving Time] contribute to misalignment between the circadian biological clock and the light/dark cycle…resulting in not only acute personal disruptions, but significant public health and safety risks.”
~ American Academy of Sleep Medicine

November 3, 2024 (at 2:00 a.m. local time) marks the end of Daylight Saving Time (DST) in the U.S. Clocks “fall back” one hour, reverting to standard time and giving millions of appreciative Americans an extra hour of sleep. Europeans turned back their clocks on October 27.

In 1908, a community in Ontario, Canada was the first in the world to implement DST, but Germany and Austria led the way at the national level when, in 2016, they implemented the practice with the rationale of saving fuel for the war effort. Other countries soon followed suit. The U.S. passed the Standard Time Act in March 1918 (under the jurisdiction of the Interstate Commerce Commission), but in response to popular protest, Congress abolished DST soon thereafter. It remained a “local option” until the passage of 1966’s Uniform Time Act, which standardized time across the country and shifted federal oversight to the Department of Transportation.

Globally, Europe and the U.S. are outliers—most countries in the world do not use DST. The practice has always been highly unpopular with farmers, in particular, and in recent years, medical organizations like the American Academy of Sleep Medicine (AASM) have chimed in, arguing that it needs to be abolished due to adverse impacts on circadian biology.

Continuing to cite reduced energy consumption as a justification for DST, the stalled-out Sunshine Protection Act—passed by the Senate but not the House in 2022—would move the nation in the entirely wrong direction, according to many experts. The act would make DST permanent, whereas AASM argues that the opposite change is needed—that is, that “permanent standard time is the best option for public health.” (According to Wikipedia, “several senators stated later that they would have objected [to the Sunshine Act] if they had known that the bill could pass.”)

Although the AASM’s primary objection to DST has to do with acute health-related effects—including increases in sleep disruption, mood disturbances, suicide, and traffic accidents—the organization also notes:

“On the Monday after the transition to DST [in the spring], volatility in stock markets in the U.S. has been observed…. [P]roposed mechanisms include the impact of sleep deprivation on frontal lobe functioning, which may result in impaired judgement and decision-making capacity.”

States can opt out of observing DST. Currently, two states (Hawaii and most of Arizona) and five U.S. territories (American Samoa, Guam, Northern Mariana Islands, the U.S. Virgin Islands, and Puerto Rico) don’t practice DST, and a handful of other states have shown interest in getting rid of the twice-a-year time changes, although opinions are split on whether to make DST or standard time the permanent status quo.

Americans who are opposed to the Sunshine Protection Act or similar actions at the state level can let their legislators at both the federal and state levels know that they support a change to permanent standard time, which aligns best with the natural circadian cycle.

Related:

Daylight saving time in the United States (Wikipedia)

Sunshine Protection Act (Wikipedia)

US Senate Approves Permanent DST Bill

Will daylight saving time end permanently in 2024? Here’s what to know

Six things to know about the political debate around daylight saving time

The 2 states that don’t do daylight saving—and how they got rid of time changes for good

Most countries don’t observe daylight saving time

Daylight saving time: an American Academy of Sleep Medicine position statement (2020)