This week across most of the U.S., the sun will set well before many folks step foot out of the office, leaving them to run errands or take walks in utter darkness. On Nov. 5, daylight saving time went out and standard time came in, lasting through March 10.

Besides scheduling stumbles and sleep habit disruptions, experts say the twice-yearly ritual can have more serious effects on human health.

Many Americans are already sleep-deprived, and a change in time messes with sleep schedules even more, says Dr. Phyllis Zee, a sleep researcher at Northwestern Medicine in Chicago, although she says “falling back” and gaining an extra hour is generally easier on the body than “springing forward” and losing one.

Chronic sleep deprivation can increase levels of stress hormones that boost heart rate and blood pressure, and of chemicals that trigger inflammation, research suggests.

“Just that one hour can change the amount of sleep you get, the quality of sleep that you get,” Zee said. Off-kilter sleep can affect people’s ability to multitask, stay alert, and even maintain their balance, making them more prone to accidents.

Molly Hart, spokeswoman for AAA’s Auto Club Group, warned that there may be an uptick in accidents on the road following the time change.

“With daylight savings coming to an end, what people really need to be focused on is their driving now in the afternoon when it’s darker earlier,” and when they may be feeling drowsy, she said.

Hawaii, American Samoa, Guam, Puerto Rico, the U.S. Virgin Islands and most of Arizona do not observe daylight saving time.

Some members of Congress have pushed to end the back-and-forth and make daylight saving time permanent.

The U.S. Senate in March 2022 passed a bipartisan bill named the Sunshine Protection Act, but it stalled in the House. The bill was re-introduced by Sen. Marco Rubio in March of this year, then referred to committee, where it has remained idle.