As most States (no, not WA) prepare to put their clocks forward by an hour this weekend – a study has scuttled claims the time-change messes with your sleep.
Australian researchers have carried out one of the most comprehensive investigations into the suggestion that daylight savings is damaging to people’s health.
Sleep expert Emeritus Professor Leon Lack and research associate Reece Kemp from Flinders University’s FHMRI Sleep Health looked at the late-stage effects of daylight savings on sleep and found no significant evidence that it caused a long-term loss in sleep or daytime functioning.
“We wanted to address gaps in current knowledge about daylight saving by exploring whether the sleep effects observed during the initial transition to the new time persisted over time or whether they were a temporary issue,” Professor Lack said.
“Those in DST states had somewhat later bedtimes and waketimes but no differences in total sleep amount nor in any daytime evaluations of sleepiness, fatigue, or other daytime measures.”
The study used data from two nationwide questionnaires which looked at sleep patterns of about 1000 people in States with daylight savings compared to those without it, including about 100 people in WA.
“We found that those who live in states that observe DST tended to go to bed and wake up later compared to those in regions that stay on standard time,” Professor Lack said.
“Importantly, the study found no significant evidence that DST was associated with a loss in overall sleep duration or a negative impact on sleep, sleep health or daytime functioning during the latter part of the DST period.
“With regards to the insomnia population, we didn’t find any difference at that point in their total sleep time or in their sleep quality, how long it took them to fall asleep, their degree of insomnia, or how they felt during the day using several different subjective measures.”
While they did tend to go to bed later and wake up later by the same amount — about half an hour later — their total sleep time was no different.
Professor Lack said our internal body clocks were not exactly timed to 24 hours in a day.
“Most people have body clocks that when allowed run free, without any environmental influence at all, take about 24 hours and ten minutes to complete a cycle before starting again,” he said.
“That means the average person has a slight tendency to delay their body clock, to go to bed a little bit later and wake up a little bit later.
“And that’s exactly what happens when we can relax on the weekends and holidays — we turn off our alarm clocks and allow our bodies to do what they normally would, which is to delay slightly night after night.”
Daylight savings starts on Sunday in States and territories except WA, Queensland and the Northern Territory, with clocks going forward one hour at 2am.