Daylight saving time research finds health and economic impacts – Editorial

The daylight-saving time switch can lead to a loss of sleep. Photo / Getty Images

THE FACTS

• Daylight saving time starts on Sunday in New Zealand.
• New US research says the biannual time-switching leads to poor health outcomes.
• The switch also has consequences for economic productivity, British research has found.

Christmas chocolate is in the shops. It’s raining during the school holidays. Must be time, then, for a springtime change of clocks.

Another 27-week stint of observing daylight saving time begins for New Zealand on Sunday.

That means we wind the clocks forward (on those increasingly rare devices not connected to the internet), lose an hour of sleep, and wake up to a darker morning.

Evidence supporting ending this seasonal time-switching, however, is mounting.

Not only has United States President Donald Trump pushed for it, but last week Californian medical school Stanford Medicine published new research suggesting people’s health would be better for it.

The study found changing the clocks twice a year disrupts circadian rhythms – the body’s sunlight-synced internal clock – leading to higher rates of stroke and obesity.

“We found that staying in standard time or staying in daylight saving time is definitely better than switching twice a year,” the senior author said.

Too much light exposure at the wrong times weakens the circadian cycle, which affects immune systems and energy levels.

The study suggested permanent standard time, prioritising more morning light, may be the least disruptive for most Americans.

The researchers’ modelling suggested it could lead to 2.6 million fewer people with obesity and 300,000 fewer stroke cases.

Prior research found a link between the daylight savings switch-on and increased heart attacks, hospitalisations and fatal crashes.

New Zealand has observed a period of daylight saving on and off since 1927. The current dates, from the last Sunday in September to the first Sunday in April, have been set since 2007.

The Government last surveyed Kiwi attitudes to daylight saving in 2008, when it found broad support.

It’s an issue unlikely to make it on to the Government’s agenda, as it navigates a more pervasive darkness – the economic gloom.

Prime Minister Christopher Luxon is “focused 100% on actually growing this economy”.

Consider this, then: A 30-year study out of the London School of Economics and Political Science last year found that people are less productive on the Monday after the switch, even though they tend to work longer.

For some, the loss of sleep can have compounding effects for six days.

But if health and economic risks are not enough to sway public opinion, the list of household tasks Kiwis are being encouraged to complete on switch-on day is growing.

It’s not just changing the clocks and checking the smoke alarm batteries now.

Auckland Emergency Management’s new campaign urges Aucklanders to use the spring-forward as a reminder to reset their emergency preparations.

Important as these tasks are, we’re already tired.