Does daylight saving time affect your health?

Get ready for an extra hour of sleep Sunday. That’s when most of the U.S. will help their clocks “fall back” an hour to mark the end of daylight saving time at 2 a.m. Daylight saving time resumes March 9, 2025, when clocks “spring forward” again.
The change adds daylight in the mornings in the fall and at the end of the day in spring and summer. The notion was first offered by Benjamin Franklin as a way to conserve energy, according to a historical look at the practice by Live Science.
In the book “Seize the Daylight: The Curious and Contentious Story of Daylight Saving Time,” author David Prerau said Franklin was ambassador to Paris, and wrote a letter to the Journal of Paris in 1784 noting that the extra sunlight could take the place of burning energy.
Still, it was a long time before the U.S. adopted the practice — and only briefly, initially. In 1918, clock times were changed during WWI. But farmers, who do much of their work in morning light, didn’t love the practice, so it went away until World War II. In 1942, President Franklin Roosevelt brought it back. After the war, though, per Life Science, “a free-for-all system in which U.S. states and towns were given the choice of whether or not to observe Daylight Saving Time led to chaos. And in 1966, to tame such ‘Wild West’ mayhem, Congress enacted the Uniform Time Act.”
Hawaii and Arizona said no thanks and have remained on standard time, though the Navajo Nation in Arizona is on Daylight Saving Time.
States didn’t have to adopt daylight saving time. But if they did, it had to be consistent. Since 2007, when the Energy Policy Act of 2005 took effect and the current timing was adopted, that means it starts the second Sunday in March at 1 a.m. and ends the first Sunday in November at 2 a.m.
In spring, you gain daylight at the end of the day but lose one hour of sleep in the change. In fall, you lose daylight at the end of the day, mornings are brighter and you get an extra hour of sleep.
Like Brussels sprouts, people either love or hate daylight saving time.
The Sunshine Protection Act in Congress would have made the clock change permanent, with more sunlight at the end of the day. It passed the Senate unanimously in 2022. But the proposal “hit a brick wall,” as The Hill described its failure to even be considered in the House of Representatives. The article said there are some fans of not changing the clock among House members, but there’s also considerable contention over what the permanent time should be.
A YouGov survey in March 2022 found just under 6 in 10 Americans would like to see daylight saving time year-round, compared to 19% who said no thanks.
The main reason for not taking up the matter in the House appeared to be the sentiment that it wasn’t that urgent at the time.
There are health claims made on both sides of the switch-time or leave-it-alone debate.
Those who dislike daylight saving time argue that it disrupts the body’s natural circadian rhythm. That includes the American Academy of Sleep Medicine, which in 2023 led a group that asked Congress to make standard time the norm year-round. Other sleep organizations have followed suit, according to ABC News.
One study published in the Journal of Clinical Sleep Medicine reported that “although chronic effects of remaining in Daylight Saving Time year-round have not been well studied, Daylight Saving Time is less aligned with human circadian biology — which, due to the impacts of the delayed natural light/dark cycle on human activity, could result in circadian misalignment, which has been associated in some studies with increased cardiovascular disease risk, metabolic syndrome and other health risks.”
Good Morning America and others have listed some pros and cons of maintaining daylight saving time year-round.
Among the pros, more sunlight, safer roads and the belief that it’s good for the economy. You’re also less apt to be affected by depression if you suffer seasonal affective disorder. Some of the health concerns on the other side may be countered by the fact that more sunlight could mean more time outside exercising or simply being active, which is good for the heart and metabolism.
Besides previously cited health concerns, the cons include more gas consumption, decreased productivity because of the draggy feeling that follows clock changes and the fact that kids may be going to school in the dark.
Time.com noted that even an hour change on the clock can mess up sleep schedules. The clock changes, but reality doesn’t. You still have to go to work or to school at the same time.
Experts suggest you start now to adjust by changing your bedtime incrementally to make the transition smooth. You can also get more sunshine to help reset your internal clock for healthy sleep, the article said.
ABC News medical contributor Dr. Darien Sutton said it’s fine to take naps if time change makes you feel tired, but limit a nap to a half-hour at most and don’t nap after 3 p.m.
“Lastly, Sutton said that when the clocks ‘fall back,’ it’s important to increase your exposure to sunlight during the day, especially in the morning and to limit your intake of alcohol and caffeine,” ABC News reported.