Most Americans on Sunday will “spring forward,” the annual ritual of advancing our clocks by an hour in a bid to capture more sunlight — while dealing with the inevitable grogginess and health risks that result.

But most Mexicans won’t adjust their clocks this spring after their country ended daylight saving time and stopped springing forward last year, a policy that local experts and officials say has led to better sleep and other benefits.

“For many people, this [clock] change was the start of a problem,” such as chronic insomnia and other sleep disorders, said Guadalupe Terán Pérez, a sleep medicine physician in Mexico City and past president of the Sociedad Mexicana Para la Investigación y Medicina del Sueño, the Mexican medical society for sleep research.

“Now, we don’t have this change — and many people sleep better,” she added, estimating that perhaps 10 to 15 percent fewer Mexicans would develop sleep disorders because the country put daylight saving time to bed.

Mexico’s decision is just the latest wrinkle in a long-running debate about how to set the world’s clocks, with the global population split across political and geographic lines. Most of the United States and many countries in Europe observe daylight saving time, moving their clocks forward an hour in the spring and rolling them back in the fall, a policy that took hold amid arguments that it would help maximize energy expenditures during World War I.

Some lawmakers in the United States are pushing to go further, endorsing a plan for year-round daylight saving time to maximize sunlight during working hours in the winter. Congressional leaders and the White House have hit the snooze button on the plan, with the legislation stalled in committee.

Meanwhile, most countries follow what’s known as standard time, which sleep experts say more naturally aligns with the body’s circadian rhythms and is linked to healthier outcomes.

Sleep experts said Mexico is right to return to standard time — and Americans should stop fidgeting with their clocks twice per year, too.

“It’s a great example for us, Europe and the rest of the world,” said Lourdes DelRosso, a sleep medicine physician at the University of California at San Francisco-Fresno and co-chair of this month’s World Sleep Day awareness event.

“Having that sense of permanence and not flip-flopping is a good thing,” added Sairam Parthasarathy, director of the Center for Sleep and Circadian Sciences at the University of Arizona Health Sciences, who said he and many of his sleep medicine colleagues support ending daylight saving time in the United States. “The feeling is [Mexico] got there before we did.”

None of the sleep researchers or U.S. sleep medicine societies contacted by The Washington Post was aware of studies into Mexicans’ sleep habits after the country’s clock changes were effectively halted last year. But they all pointed to existing research showing twice-a-year clock changes are linked to health problems, such as elevated risk of heart attack and stroke, arguing the evidence is clear that “springing forward” carries unnecessary risks.

“While we approve of Mexico going to standard time and do think that it will be best for outcomes like health and mental health, we don’t know quite yet,” said Karin Johnson, a sleep medicine physician who is a member of the American Academy of Sleep Medicine’s advocacy committee and co-chair of the Coalition for Permanent Standard Time.

Several physicians shared anecdotes affirming Mexico’s new policy, with Parthasarathy recounting his team’s care for patients along the border, and Terán Pérez discussing her experience treating patients inside the country.

“Our clinical experience shows improved sleep in most people during this period of time,” Terán Pérez said, discussing her and her colleagues’ work in Mexico City.

In Mexico, the time had come

While Americans have spent more than a century living under daylight saving time, Mexicans have been far more ambivalent about clock changes. The country adopted daylight saving time in 1996 — copying the U.S. policy to spring forward in April and “fall back” in October — but its leaders balked when U.S. lawmakers extended daylight saving time by three weeks in 2007.

Mexico in 2022 moved to abolish the practice altogether, a shift backed by President Andrés Manuel López Obrador. In a public messaging campaign, the Mexican president and top aides argued that the clock changes had led to health issues, educational problems such as student drowsiness, and other drawbacks. López Obrador’s administration released polling showing that 71 percent of Mexicans opposed daylight saving time.

“The first thing we should consider is that the choice of daylight saving time is political and can therefore be changed,” Jorge Alcocer Varela, Mexico’s health secretary, said at a news conference in July 2022.

“If we want to improve our health, we should not fight against our biological clock,” he added, arguing that daylight saving time was unnatural and calling for a return to “God’s clock” instead.

The president’s legislation was quickly taken up by Mexican lawmakers, such as Cuauhtémoc Ochoa Fernández, who helped shepherd the time change through the country’s legislature.

“Daylight saving time did NOT meet the savings that were promised to Mexicans; on the contrary, electricity costs increased and it affected their health,” Ochoa wrote in a social media post in October 2022, as government officials formally ended daylight saving time and much of Mexico prepared to “fall back” for the last time.

Some areas of Mexico, including cities near the U.S. border, have preserved daylight saving time.

One reason for Mexicans’ cool feelings toward daylight saving time: Their days are frequently sunnier than those of their neighbors north of the border, particularly in the darkest times of the year. That has led to less public pressure to shift hours in an attempt to stretch daylight.

For instance, on Dec. 21 — when Earth’s northern axis will be tilted the farthest from the sun all year — Mexico City will receive about 90 minutes more sunlight than Washington, because Mexico’s capital city is far closer to Earth’s equator.

Politicians on the clock

In the United States, daylight saving time has led to unusual bipartisan alliances, with lawmakers brought together by geography rather than politics.

For instance, the Sunshine Protection Act, which would create year-round daylight saving time, is supported by Sen. Rick Scott (R-Fla.), rated by one data-analysis website as the most conservative senator in the last Congress, and Sen. Edward J. Markey (D-Mass.), rated the second most liberal senator.

“This is not politics here. This is doing something for the American people,” said Sen. Tommy Tuberville (R-Ala.), a backer of the bill, arguing that it would help farmers and other residents of his mostly rural state enjoy more time outdoors.

The battle lines around the issue, which reflect how time zones are drawn, are well established: Daylight saving time in the winter would favor coastal cities like Boston and Miami more than Midwestern cities such as Detroit and Indianapolis, where the sun would not rise until after 9 a.m.

The political risk enveloping the issue also is well established. U.S. lawmakers in 1973 enacted year-round daylight saving time, arguing it was a necessary move during an energy crisis. But Congress quickly repealed the law amid widespread reports that darker winter mornings led to more car accidents and drearier moods.

The Senate’s decision to abruptly pass year-round daylight saving time two years ago also provoked a flurry of lobbying, freezing the bill in the House as lawmakers said they couldn’t decide what to do.

“There isn’t a consensus, in my opinion in the House, or even generally at this point, about whether we should have standard versus daylight saving as the permanent time,” then-House Energy and Commerce Committee Chairman Frank Pallone Jr. (D-N.J.) told The Post in March 2022. “Immediately after the Senate passed the bill, I had members come up to me on the floor and say, ‘Oh, don’t do that. I want the standard time.’”

Tuberville said he’s considering the same legislative maneuver that he and other senators executed two years ago, when they bought their permanent daylight saving time bill directly to the floor and passed it in a voice vote — to the surprise of some senators who weren’t in attendance, and many Americans who weren’t even aware that permanent daylight time was under consideration in Congress.

“Can we pull it off again on the Senate floor? I don’t know, but we’ve got a lot of Democrats for it,” Tuberville mused.

Advocates for permanent standard time have been working to mount a political counterattack, noting that Hawaii and most of Arizona already have opted out of daylight saving time and other states can join them. States are allowed to enact permanent standard time, but permanent daylight saving time is not federally approved.

Mexico’s experience ending daylight saving time offers a “learning lesson” on the need for proactive communication and technical fixes, said Johnson, of the American Academy of Sleep Medicine. She noted that computer systems around Mexico had to be quickly updated to accommodate the new time rules.

But “in the long term, it’ll be easier,” Johnson added, because Mexicans don’t need to shift their clocks again.

While U.S. leaders toss and turn over time-change policies, the issue is seen as settled in Mexico.

“Since [daylight saving time] was eliminated, no one has talked about it again,” a representative for Ochoa wrote in response to emailed questions from The Post. “There is no interest in reestablishing Daylight Saving Time, since to date there is no indicator that shows its benefits.”