Alarm clocks may have long-term health consequences. Photo: 123RF
American biology professor Erik Herzog, who studies circadian rhythms, says staying on permanent standard time may be healthier for us than daylight savings.
Clocks went back an hour this morning, as NZ daylight savings came to an end.
Daylight saving was introduced in 1927 and has taken several different forms, before the current format was implemented in 2007.
Only a third of the world embraces daylight savings and most Americans no longer want it, although they can't agree on what should replace it.
"We have ongoing bills being debated in Congress, usually 2-3 bills per state in all 50 states," Professor Herzog from Washington University told Sunday Morning.
"This year, for the first time, we have more bills in favour of permanent standard time than ever before."
Herzog said standard time may be better for humanity. People can wake up in the dark and go to bed while it is still light during daylight savings time, but they also need early morning light to synchronise their internal clock and not depend on alarm clocks to wake up.
Changes to this circadian alignment are akin to jetlag, where the body takes several days to adjust to changes in time zones.
"If you're using your alarm clock to wake up, as many of us do, you're waking up unnaturally," he said. "It turns out that alarm clocks and being forced to wake up when you're not done sleeping has long-term health consequences.
Professor Erik Herzog said standard time may be better for humanity. Photo: Joe Angeles/ Washington University / Supplied
"I think it's doing you plenty of good - you feel good, your mood is elevated - but in terms of synchronising your circadian clock to local time, that light is tending to delay your bed time and delay your wake-up time.
"The following morning, when it's time to get up and go to work or school, your biological clock is saying, 'No, no, no, I need to sleep for another hour', but your alarm clock is saying social schedules need you to get out of bed.
"You're sleep-depriving yourself and stressing yourself out, and we think those things have negative consequences on things like heart health and metabolic health.
"I love sunshine in the afternoon, sure. I love summertime, sure, but I think daylight saving time is not good for our health the way we run it now."
Herzog observed that 'falling back', as we have just done, can be beneficial, compared to 'springing forward'.
"We see in repeated studies around the world a decrease in car accidents the day after falling back," he said. "We see a decrease in heart attacks, and we see a decrease in a number of other health and crime-related statistics.
"In contrast, when we switch to daylight savings time and lose an hour of sleep, we see a net increase in heart attacks, car accidents and other bad things that last for about three days, but that's not the main reason I'm advocating for permanent standard time."
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