Time travel is real, and people across the country do it together twice a year — as the United States goes in and out of daylight saving time.
On Sunday, our digital clocks will automatically move most Americans from 2 a.m. to 3 a.m., which will cost them an hour of sleep. Here's everything you need to know about the history of daylight saving time and some critics calling for it to be ditched.
Where did daylight saving time come from?
Congress passed a law mandating the transition to daylight saving time in March 1918, when the United States was trying to conserve fuel and energy for the war effort and advanced clocks to take advantage of natural sunlight in the evening. (Germany did the same in 1916.) The public wasn't very interested in the idea, so Congress passed another law over President Wilson's veto of ending federal mandate in October 1920.
At the request of President Franklin Roosevelt, Congress passed a year-round version of daylight saving time in 1942, calling it “wartime.” Although that requirement lapsed in 1945, many states and cities adopted their own daylight saving time mandates, creating inconsistencies that caused headaches for the transportation industry, the Congressional Research Service said in a 1998 report. Congress responded in 1966 with the Uniform Time Act, which Establish common start and end dates for daylight saving time across the country.
By the way, researchers have since discovered that daylight saving time is not efficient at conserving energy.
What are the pros and cons of daylight saving time?
Today, implementing daylight saving time is controversial, with arguments for and against. Public health experts have found that losing an hour of sleep increases the chances of having a heart attack or stroke, but criminologists have found that an extra hour of daylight in the evening can reduce crime rates. The impact on traffic safety is unclear. Drowsy drivers increase the likelihood of collisions, but increased visibility during your evening commute home from work can reduce the likelihood of collisions, too. Daylight hours mean that more school days start before the sun is fully up, prompting complaints from parents who don't like their children having to walk to school in the dark.
JPMorgan Chase found that daily spending on credit and debit cards rises by 0.9% when daylight saving time begins and falls by 3.5% when it ends. So some economists favor daylight saving time because of the rise in consumer spending during days when the time changes. Meanwhile, the American Academy of Sleep Medicine has called for the end of daylight saving time, encouraging lawmakers to stick to standard time, because it better aligns daylight hours with the times we typically wake up and go to bed.
What happens when you lose sleep?
Dear A said. Chronic sleep deprivation has long-term consequences on your health, including a higher risk of heart disease and type 2 diabetes, said Seixas, associate director of the Center for Translational Sleep and Circadian Science at the University of Miami Miller School of Medicine. Obesity, Alzheimer's disease and Parkinson's disease.
Switching to daylight saving time causes sleep loss only once a year. But in the short term, individuals can experience “impaired cognitive function,” weakened immune systems, and disrupted circadian rhythms.
What is circadian rhythm and why does it matter?
Seixas said people's circadian rhythms are like an internal clock that helps regulate hormones, metabolism and emotional responses.
“Exposure to daylight synchronizes our internal clock with the external environment, enhancing our sleep-wake cycle,” he told The Times via email. Sun exposure is crucial in indicating when it is time to be alert and when it is time to sleep. He added that lack of adequate exposure to daylight “disrupts the circadian rhythm, leading to sleep disturbances, mood disorders, and other health problems.”
Any policy on changing the clock needs to “balance the benefits of longer daylight hours with the potential negative effects on sleep and health,” Seixas said.
What are lawmakers trying to do about daylight saving time?
The Uniform Time Act allowed states to make standard time permanent, eliminating semiannual time changes. Hawaii and Arizona do not adhere to daylight saving time (although the Navajo Nation in northeastern Arizona does), and neither do the US territories of Puerto Rico, American Samoa, Guam, the US Virgin Islands, and the Northern Mariana Islands.
You may remember that Proposition 7, approved by Californians in 2018, allowed state lawmakers to propose switching to permanent daylight saving time. But as the proposal acknowledges, the state does not have the power to make such a change unless Congress amends the Uniform Time Act.
At the federal level, Sen. Marco Rubio (R-Fla.) and a bipartisan group of co-sponsors have proposed the Sun Protection Act to extend daylight hours year-round. The bill passed the Senate unanimously in 2022, but died in the House; The latest version and its counterpart in the House of Representatives have not yet received a vote in either chamber.
What is the best way to prepare for daylight saving time?
Seixas has a handy acronym he uses to help people prepare for that lost hour of sleep: SPRING.
“S” means “sunshine”. Staying outdoors during the day helps your body stay alert until it's actually time to go to bed. “P” means “Ready to Modify”. Go to bed early because you will lose an hour of sleep, and make sure not to drink caffeine too late in the day. “R” means “routine”. Try to create bedtime habits that prepare you for sleep. Instead of watching TV or browsing social media before bed, turn off your devices and read a book before curling up on your blanket. “I” means “uniqueness.” Get to know your body and find out what works best for you. “N” stands for “only nap if you're tired, but early.” Try to take a nap early in the day and keep it short; Naps longer than 30 minutes can leave some residual sleepiness that is difficult to shake. “G” means “gradual ease into it.” On these days before daylight, try to go to bed gradually earlier and wake up earlier to prepare your body for the lost hour.
If you have pre-existing conditions and want to know how to reduce your increased risk of having a stroke or heart attack, Dr. Hitender Singh Gurm, a cardiologist and chief medical officer at the University of Michigan Health System, recommends a few extra steps besides getting adequate sleep. Jorm advises his patients not to smoke and to monitor their blood pressure, diabetes and cholesterol levels to ensure they remain at safe levels. Of course, regular exercise is always recommended to help with long-term health issues.
