After 12 months in which bright spots were in seriously short supply, the clocks moved up an hour overnight, and on Sunday twilight will linger past 7:30 p.m. and push back the darkness ever longer until the solstice.

If a coalition of U.S. senators have their way, the clocks will never go back.

Yet the nation remains deeply divided on the question of standard vs. daylight saving time, and why do so many of the world’s leading sleep researchers believe DST is a terrible idea?

They hold that snipping an hour of the clock further exacerbates a phenomenon known as “social jet lag,” the gap between the sleep we need and what we actually get at the clock hands of an uncaring society that forces us to sleep less on weekdays and pay back the sleep bank on weekends.

Given those chronic discombobulations, one might reasonably ask, what difference could one measly hour make to settling our sleep-bank accounts. Wouldn’t that be akin to adding another penny to the national debt — $28 trillion at last look?

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“This is a common misconception,” M. Adeel Rishi, a pulmonology, sleep medicine, and critical care specialist at the Mayo Clinic in Eau Claire, Wisc., said this week. “A sudden change by one hour can translate into throwing back our body clock’s relationship to social clock by several weeks.”

Jet lag, typically a sensation of fatigue and at least modest disorientation, is a staple anytime one has traveled across time zones. The symptoms of social jet lag can be similar, researchers say, the difference being that the sufferers haven’t gone anywhere.

About ‘social jet lag’

Our lives are driven by three separate clocks — body, sun, and social — all interrelated but each keeping time in its own way. So says Till Roenneberg, a German researcher who specializes in chronobiology and is credited with originating the term “social jet lag.” He estimates that it might affect two out of three people.

The body clock is the internal timepiece, responding to light and darkness, Roenneberg said in a 2019 paper. The body’s “circadian” life is tied to the sun, which is a more powerful stimulus than artificial light.

While it is related to the sun’s daily comings and goings, the social clock — the one whose time is displayed on clocks, phones, and computers, and the one the boss is most likely to care about — is a “construct ... the local time determined by policy.” (Feel free to share that with the boss.)

When we change the clocks, Roenneberg argues, “We do not change time, we only change social clocks. ... Days are not becoming additionally longer and the sun does not set additionally later.” Flying across time zones, the body is exposed to new light-dark cycles. That tends not to happen when one enters a new time zone while remaining in one’s own bed.

According to the social clock, we’re all about to move to Bermuda. Don’t get your hopes up.

Why do we care?

Research on the consequences and duration of the effects of time changes is conflicting, and Roenneberg acknowledges that pushing back the night clearly has some social benefits, which would include that ultimate light dessert after dinner, the twilight walk.

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However he said that social jet lag is associated with obesity, smoking, and excess alcohol and caffeine consumption.

In the fall the American Academy of Sleep Medicine endorsed ditching the switching, citing “significant public health and safety risks,” from sleep deprivation to higher blood pressure, to an assortment of things you probably couldn’t pronounce.

Saying it “aligns best with human circadian biology and provides distinct benefits for public health and safety,” the Academy endorsed year-round standard time. It has backing from the National Safety Council, the National PTA, and a variety of health organizations.

It likely will remain a tough sell. Those late-arriving nights are mighty popular among the citizenry, not to mention among restaurants with outdoor seating, youth-sport leagues, and makers of barbecue grills.

A very brief history of time in America

Time was that towns relied on a local authority, perhaps an astronomer, to calculate a true “solar noon” and official clocks would be calibrated accordingly, said Carlene E. Stephens, curator at the Smithsonian Institution’s National Museum of American History.

Before 1883, she pointed out, locations marked time by longitudes, so Philadelphia was a few minutes behind New York City (nothing new there), and a few minutes ahead of Washington, with each degree of longitude equaling a four-minute difference. Actually, that would have been more in keeping with body time.

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The railroads that redefined America decided they couldn’t function under such a nonsystem and divided into four time zones. Not everyone wanted the railroads telling them what time it was.

Finally, in 1918, Congress made the time zones the law of the land and instituted daylight saving time, an idea that began in Germany on May 1, 1916, as a war conservation measure. It spread across Europe and arrived in the United States in 1918 when Congress included it in a bill that standardized the national time system.

It first went into effect that year, on March 31, to the outrage of some religious leaders who complained it played havoc with sunrise Easter services.

Year-round DST was attempted twice, during World War II, and at the end of 1973 in response to an energy crisis. That was supposed to be a two-year trial period but ended after 10 months: Among other issues, parents raised safety concerns about their kids going to school in the dark.

As for any move toward year-round standard time, if anything the nation has been creeping in the opposite direction, and Sen. Marco Rubio (R., Fla.) and a bipartisan coalition have introduced a bill to keep the clocks on DST permanently.

Once upon a time the year was roughly divided between daylight and standard, but Congress has expanded DST to eight months, from the second Sunday in March to the first Sunday in November.

That had a lot to do with candy manufacturers, who wanted to make sure trick-or-treaters had light for Halloween.