The risk of getting into a fatal car accident increases significantly the week after spring's daylight saving time switch, according to a study published in Current Biology.
Researchers examined that risk of car accidents rising in the spring, when many states switch to daylight saving time, resetting clocks an hour ahead. People lose an hour in states that make the switch.
Researchers used data from a large U.S. registry, which included 732,835 fatal motor vehicle accidents recorded in all states from 1996 to 2017.
They found that in the week after the switch to daylight savings time, the risk of getting into a fatal motor vehicle accident increased by 6 percent.
They also found that the risk of fatal accidents after the time change is highest in the morning.
Researchers did not find a similar spike in car accident risk after the transition to standard time in fall.
They concluded that sleep deprivation and "circadian misalignment," or a disruption of the circadian rhythm that regulates sleep-wake cycles, may cause the increase in fatal car accident risk.