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Health experts say making daylight saving time permanent is a terrible idea. Permanent standard time, on the other hand ...

Advocates of ending standard time have for years pointed to studies showing adverse health effects from changing the clocks.John Tlumacki/Globe Staff

War is raging in Ukraine. The coronavirus looks like it’s making a comeback overseas. Yet the Senate this week gave winter-weary Americans something different to fight about: the prospect of making daylight saving time permanent.

The Senate’s unanimous passage of legislation Wednesday to do just that sparked intense reactions, from sun-starved Northeasterners thrilled over a potential reprieve from 4:30 p.m. winter sunsets to exasperated voters wondering why Congress can’t manage to work on more pressing matters.

“It’s about time. No pun intended,” Ari Silverman responded in a survey of Globe readers.

“There is some kind of prejudice against us morning people,” quipped Lillian Reynolds.

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“Not really sure why Congress thinks this is important — we have a mess going on in Europe and lots of things to deal with more important,” added Scott Barnett. “But I guess they need Joe Manchin to vote FOR something for a change.”

Senators from both parties celebrated their bipartisan progress, claiming their so-called Sunshine Protection Act would deliver numerous health benefits — along with “more smiles,” according to Massachusetts’ own Senator Edward J. Markey, a longtime champion of the effort.

Health experts, however, are not smiling about the development.

Ending the back-and-forth time switch between standard and daylight saving time would put an end to adverse health effects that come from the change, but doctors and sleep experts said Congress is going in the wrong direction. The better choice, many said, would be to make standard time — the zone we inhabit from November to March — the one true time.

“In their zeal to prevent the annual switch, the Senate has unfortunately chosen the wrong time to stabilize onto,” said Dr. Charles Czeisler, chief of the Division of Sleep and Circadian Disorders at Brigham and Women’s Hospital. “What the Senate passed yesterday would require all Americans to start their work and school an hour earlier than they usually do, and that’s particularly difficult to do in the winter, when the sun is rising later.”

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Abandoning standard time is about more than enduring groggy, dark winter mornings. Shifting the day forward an hour for good would disrupt humans’ natural circadian rhythms, and that’s not good for us, experts say.

“Our internal clock is not connected to the clock on the wall. It’s connected to the sun clock, because that’s how it’s been for millennia,” said Dr. M. Adeel Rishi, a pulmonology, sleep medicine, and critical care specialist in Indianapolis and vice chair of the American Academy of Sleep Medicine Public Safety Committee. “Regardless of what happens on the clock on the wall, it does not change the relationship between our internal clocks and the sun clock.”

Researchers have identified the ill effects a possible move to permanent daylight saving time could bring by looking at the western edges of time zones, where the sun rises and sets later compared with the eastern edges.

If daylight saving time were permanent and universal.andy woodruff
Daylight saving time as it is currently observed.Andy Woodruff

A 2017 paper found that people who live on western edges of time zones had increased risk of a long list of cancers, including stomach, liver, prostate, and non-Hodgkin lymphoma for men. In women, researchers found higher rates of cancers of the esophagus, colorectal, lung, breast, and corpus uteri. Chronic lymphocytic leukemia was more common across the board.

If daylight saving time were abolished and we moved to permanent standard time.Andy Woodruff

There are also associated increases in conditions like diabetes, sleep disorders, and mental health conditions, said Czeisler, though New England is far enough east to not feel those effects as severely as other parts of the country.

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Think back to the darkest day of 2021, the winter solstice on Dec. 21: The sun rose at 7:08 a.m. and set at 4:16 p.m. Boston got 9 hours and 8 precious minutes of sunlight, which, for many people, fell during work or school hours.

A permanent switch to daylight saving time would mean that next winter solstice, the sun wouldn’t rise until after 8 a.m.; sunset would arrive at about 5:15 p.m. In places like Indiana, at the far western edge of Eastern time, the sun wouldn’t rise until after 9 a.m. in the winter.

Congress, of course, can’t extend the amount of sunlight on a dark winter day. It can only play around with the clock, shifting the hours in which people are awake, going to work or school, running errands.

And lawmakers have switched to permanent daylight savings before — three times, during both world wars and during the energy crisis of the 1970s. During the world wars, it was hailed as an effort to keep wartime manufacturing running later into the evening, said David Prerau, who wrote a book on the topic.

Other countries have tried permanent daylight saving as well. The efforts usually end up being unpopular and getting reversed.

The ’70s effort, a purported way to cut costs in response to the energy crisis, was supposed to be for two years, but was so unpopular that Congress voted to end it a year early, Prerau said.

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Current federal law allows states to opt out of observing daylight saving time and remain on standard time year-round. Nonetheless, 48 states engage in the biannual clock-switching exercise; only Hawaii, most of Arizona, and most other US territories do not.

Indiana joined the daylight saving crew in 2006; prior to that much of the state ignored the practice. Researchers found that the 2006 change led to an increase in residential energy usage that cost the state’s households an estimated $9 million per year more in electricity bills because people were more often awake when it was dark and cold out, and increased pollution.

Many experts agree with the Senate that shifting the clock twice a year can cause adverse health effects, most from loss of sleep. Over the years, some researchers have shown the switch from summer to winter time is linked with disturbed sleep, more heart attacks, and a slight rise in fatal car crashes.

But that doesn’t mean the move to permanent daylight time is the right one, Rishi said. The American Academy of Sleep Medicine has advocated for a permanent switch to standard time, or the winter clock.

“I think it’s a good idea to get rid of the switch, absolutely,” he said. “It doesn’t make sense to do the back and forth.” But the right place to end up is permanent standard time, he said.

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Outside of the groggy first days after we lose or gain an hour, studying the long-term health effects of shifting the clocks is difficult because there are so many other factors involved.

A 2017 study from Denmark, for instance, found an 11 percent increase in depressive episodes after the clocks shifted to winter time, which took about 10 weeks to dissipate.

But shifting the clocks didn’t necessarily cause those depressive episodes, the study’s authors wrote.

Dr. Karin Johnson, medical director of Baystate Health’s Regional Sleep Program in Springfield, Mass., said there’s likely a simpler reason: Days are shorter in the winter.

When she sees patients with seasonal affective disorder or other mood problems related to winter, Johnson recommends bright light as treatment.

“But we specifically recommend bright light in the morning, because we know that more light exposure in the evening makes you stay up later and be more sleep deprived,” she said.

Johnson is a board member of Save Standard Time, a nonprofit that has long advocated for a switch to permanent standard time, and is now lobbying Congress to try to stop the Sunshine Protection Act from becoming law.

“We’re very disappointed, especially how quickly it was passed through the Senate without any discussion at all,” she said.

Johnson said the change would disproportionately affect teenagers, who naturally have a delayed internal schedule, and essential workers, who are often minorities and people of lower socioeconomic status and have early work start times.

The tradeoff just isn’t worth it for a small sliver of light after 5 p.m. in winter, she said.

“The days are just so short, you actually aren’t getting any meaningful light at the end of the day, and you’re losing so much meaningful light that’s even more important at the beginning of the day,” Johnson said.


Gal Tziperman Lotan can be reached at gal.lotan@globe.com or at 617-929-2043. Sahar Fatima can be reached at sahar.fatima@globe.com Follow her on Twitter @sahar_fatima.