Linked to several chronic diseases, the modern trend of less sleep may harm Kiwis.
By most reasonable estimates, modern life means about a third of New Zealanders suffer from not enough sleep or sleep deprivation. That's according to a range of studies both here and overseas.
It's an annoyance, an inconvenience which often leaves people tired, grumpy and a little unproductive, right?
It's rather more than that. Professor Matthew Walker, director of the Centre for Human Sleep Science at the University of California, Berkeley, said in an interview with the Guardian in September last year: "There is a catastrophic sleep loss epidemic [affecting the world]."
He says there are powerful links between sleep loss and, among other things, Alzheimer's disease, cancer, diabetes, obesity and poor mental health. He counts anything under seven as sleep deprivation (other experts say six is the tipping point). Last year Walker released a book (Why We Sleep) designed to explain the health risks and encourage people strive for eight hours sleep.
These warnings can be taken to apply to New Zealanders too. Successive surveys over the past few years have consistently painted a picture of lost sleep among a large slice of the Kiwi public.
In 2015, a Southern Cross Health Society survey revealed almost a quarter of Kiwis felt tired or fatigued every day, rising to 36 per cent for under-30s.
In 2016, a Colmar Brunton survey said 60 per cent felt tired due to lack of sleep and that 36 per cent got only 4-6 hours a night. A separate survey in the same year said 35 per cent of New Zealanders were sleep deprived (especially women) and, according to other research published in the Listener, 37 per cent of 30 to 60-year-olds report never or rarely getting enough sleep in various health surveys from 1999-2008 and 2013-2014.
A report from Britain's National Health Service (NHS) says the one in three Britons suffering from poor sleep are at risk of serious medical conditions, including obesity, heart disease and diabetes, shortening life expectancy: "It's now clear that a solid night's sleep is essential for a long and healthy life."
According to Walker, after just one night of only four or five hours' sleep, your natural killer cells - the ones that attack the cancer cells that appear in your body every day - drop by 70 per cent.
So what is driving sleep deprivation in New Zealand? Modern life is a suspected cause of many new ills - sleep deprivation among them. Walker says it has become a badge of honour to keep going until there is nothing left in the tank.
Stress, anxiety, juggling the demands of work and family and being connected to technology are among the suggested causes. Caffeine, alcohol, eating late and getting home last have also been mentioned as "sleep stealers".
New Zealand sleep expert Rachel Lehen, from Fatigue Management Solutions, says sleep issues she is treating on a daily basis include "poor sleep efficiency; people struggling to fall asleep, those waking up and not getting back to sleep and having fragmented sleep patterns that are often due to stress."
She says many Kiwis are only fitting in sleep with the leftover hours in the day rather than prioritising it as part of a healthy lifestyle: "This is a vicious cycle as the lack of sleep impairs our ability to concentrate and make good decisions. It can impact our food choices as well as our motivation to exercise and keep moving the following day."
A national business development manager and mother of three Cathy Weck estimates she gets about 5 hours' sleep a night: "Who has time for sleep? My life is too full to fit into just 16 of the 24 hours a day."
Her high pressure job requires long hours. She has a commute of around two hours a day and fits in training for her marathons: "I'm texting or emailing in the evenings and it's not unusual for me to be vacuuming at 6am before I head off to work."
So, what to do to promote healthy sleep patterns? Southern Cross Health Society gives the following guidelines: