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Should daylight saving time be made permanent? Why health experts say no

Efforts are underway to stick with one time all year long. Doctors say it shouldn't be DST.
There's strong momentum to stop changing the clocks twice a year, with most Americans in favor of a national, fixed, year-round time.
There's strong momentum to stop changing the clocks twice a year, with most Americans in favor of a national, fixed, year-round time.TODAY illustration / Getty Images
/ Source: TODAY

When most of the country springs forward to daylight saving time this Sunday, Jay Pea won't be changing his clock. He has personally observed permanent standard time as a "modest act of civil disobedience" for 30 years.

"Standard time is the real time and DST is a false construction," Pea, 42, who lives in San Francisco, California, told TODAY.

"When I attempt to be on daylight saving time, I feel that disconnection... we turn (watches) forward an hour to trick ourselves into waking earlier, which is just disingenuous, it's dishonest."

The amateur astronomer is the founder of Save Standard Time, a nonprofit organization that's part of a push to stop the country from moving in and out of daylight saving time, which is currently in place from mid-March until early November.

There's strong momentum to stop changing the clocks twice a year: 63% of Americans are in favor of a national, fixed, year-round time, according to a 2020 survey by the American Academy of Sleep Medicine.

But beyond the question of whether we should stop changing the time twice a year, there’s the issue of which time should be made permanent: standard or daylight saving time.

Pea founded his organization in 2019 after becoming alarmed by extensive efforts in favor of perpetual daylight saving time. He's suspicious of "Big Oil, Big Golf, Big Retail and Big Candy" lobbying for the change to make more money as extended evening daylight leads people to drive, shop and play more, and spend more on candy during Halloween.

In the last four years, 15 states have enacted legislation or passed a resolution to provide for year-round DST, if Congress were to allow such a change, according to the National Conference of State Legislatures.

On Tuesday, several senators reintroduced the Sunshine Protection Act, which would make daylight saving time permanent across the country.

But sleep experts worry that’s the wrong way to go and could pose health risks.

Can daylight saving affect your health?

There is no biological need for humans to change the time twice a year, though the health impact can be concerning, sleep experts said.

“There is no great reason to switch back and forth… it is disruptive in a lot of different ways,” Dr. Meir Kryger, a sleep researcher and professor at the Yale School of Medicine in New Haven, Connecticut, told TODAY.

“We have evidence accumulating that it’s dangerous to do this,” added Dr. Charles Czeisler, chief of the division of sleep medicine at Brigham and Women’s Hospital in Boston and professor at Harvard Medical School.

The effects are particularly evident in the spring, when people face a greater risk of heart attack and stroke in the days after losing one hour of sleep. There are also more car accidents, medical errors and hospital admissions.

The change causes a phase shift of our circadian rhythm — the body’s internal clock — and exacerbates the chronic sleep deficiency Americans already experience.

“Many people in our society are living on the edge in terms of the amount of sleep that they’re getting,” Czeisler said.

The fall time change has consequences, too, potentially increasing symptoms of depression in people whose depression is linked to darkness, Kryger said.

What are the negative effects of daylight saving time?

In 2020, the American Academy of Sleep Medicine called for the seasonal time changes to be abolished in favor of year-round standard time, noting it most closely matched our sleep-wake cycle.

“The standard time is more standard as far as the body is concerned,” Kryger noted.

Daylight saving time, on the other hand, is less aligned with human circadian biology because it means more darkness in the morning and more light in the evening, disrupting the body’s natural rhythm, the academy cautioned.

The Society for Research on Biological Rhythms also advocated for permanent standard time based on studies that found that the further west people lived within a time zone — thus experiencing a later sunrise that would also come with DST — the more health problems they had, including increased rates of cancer.

“It affects when you are exposed to light and light impacts the release of the sleep-promoting hormone melatonin,” Czeisler said. “Melatonin is also an oncostatic agent, meaning that it slows the growth of cancer.”

Beyond health, there are also safety concerns, especially when it comes to children waiting for school buses on dark mornings.

If daylight saving time were permanent, the sun would not rise in December and January until after 9 o’clock in major cities like Detroit, Indianapolis and Seattle, and about 8:30 a.m. in New York and Chicago, according to David Prerau, author of "Seize the Daylight: The Curious and Contentious Story of Daylight Saving Time."

"If we're on DST in the winter, people would be going to school and work in the dark for a quarter, a third, maybe even half of the year, depending on where they live," Pea said. "I don't think most people realize how hard the dark winter mornings are."

Why do we have daylight saving time?

The concept of extending daylight hours to conserve power has been around since World War I. It was thought a later sunset would lead to less lamp use in the evening, but the savings have been underwhelming — about 0.5% in total electricity per day.

DST became law in the U.S. in 1966, with the start and end dates extended twice since, leading to the current eight-month span.

States can opt out of daylight saving and stick with standard time permanently — which is the case with Arizona, Hawaii, the U.S. Virgin Islands and Puerto Rico.

But making daylight saving time permanent year-round is not currently allowed by federal law and would require an act of Congress to make a change, according to the National Conference of State Legislatures.

Are we going to stop changing the clocks?

Scott Yates, a “lock the clock” activist in Denver, advocates following the European Union, which plans to stop the clock changes and let member countries decide whether to permanently stick with winter or summer time. But the efforts have reportedly slowed in recent months and the status quo is expected to remain in place until 2022.

Yates believes it should be up to each state in the U.S., even though that might result in a patchwork of times.

“Once the states are locked into their time zone, we'll know what their relationship is to our home states, and that won't change, so less confusion overall,” he said.

“I am hopeful that a combination of state legislative action and real bipartisan efforts in Washington will end (seasonal clock changes) in the next year or two. When we see that Europe can do it, we'll know that we can do it, too.”