The countdown is on to “spring ahead” this weekend.
Daylight saving time begins Sunday, when clocks move forward from 2 a.m. to 3 a.m., costing people an hour of sleep.
With the switch just one more day away, here are five things you need to know about daylight saving time:
1. Your health could be affected
Even though the clocks are only jumping ahead by one hour, people could feel increased fatigue after this weekend.
Similar to jet lag, daylight saving time sets off the body’s circadian rhythm, which is the body’s wake/sleep cycle that’s based on the sun.
Daylight saving time could also make it harder for people to fall asleep at night and wake up in the morning. Effects typically wear off in about a week to 10 days.
2. Heart attack and car crash data increase
During the first few days after the spring time change, fatal car crashes temporarily spike, according to a study of U.S. traffic fatalities, The Associated Press reported.
The risk was highest in the morning, attributed to sleep deprivation.
The American Heart Association says studies suggest an uptick in heart attacks on the Monday after daylight saving time begins, and in strokes for two days afterward, according to AP.
This could be attributed to the abrupt circadian disruption, which exacerbates factors such as high blood pressure in those who may already be at risk.
3. Not all countries participate
Only about a third of the world’s countries practice daylight saving time, with the majority of them being in Europe, according to Pew Research Center.
Daylight saving time is not observed in all of the United States, either.
Hawaii, American Samoa, Guam, Northern Mariana Islands, Puerto Rico, the Virgin Islands and most of Arizona do not adhere to daylight saving time, according to the U.S. Department of Transportation. The Navajo Nation in Arizona does not opt out of daylight saving time, the AP said.
4. There’s been talk about eliminating it
Before President Donald Trump began his second term, he promised to eliminate daylight saving time, according to The Associated Press.
But despite consistent chatter pushing for ending the time change, the bipartisan bill named the Sunshine Protection Act to make daylight saving time permanent has repeatedly stalled in Congress.
The American Medical Association and the American Academy of Sleep Medicine agree that the twice-yearly clock change should end, but they say keeping standard time year-round better aligns with the sun — and human biology — allowing for more consistent sleep, the AP reported.
About 1 in 10 U.S. adults favor the current system of changing the clocks, according to an AP-NORC poll conducted last year. About half oppose that system, and some 4 in 10 didn’t have an opinion.
5. Daylight saving time began during World War I
As part of an energy conservation effort, daylight saving time was established in the United States during World War I, according to Time.
However, there are conflicting reports on whether it actually helps conserve energy, Time said.
Daylight saving time aligns the daylight hours with the times people are most active — during the section of the year when the weather is warmer.