Data shows too many Kiwis aren’t getting enough sleep. Ahead of World Sleep Day, science reporter Jamie Morton talks to experts about what we’ve been learning.

Poor sleep is a serious problem

We all spend,
on average, a third of our lives asleep. But tonight about a third of Kiwi adults won’t get enough of it.

We need it to recharge our minds and bodies, back up our memories, bolster our immunity and keep our emotions in check.

If we don’t get enough, the neurochemicals that help us slumber will work during the day.

That makes it tougher to concentrate, problem-solve, think creatively and act decisively, which can spell disaster at work – imagine trying to operate heavy machinery or drive a truck.

Fatigue is a factor in hundreds of road crashes each year.

It also affects the hormones that regulate our appetite, making us more likely to reach for those heavy, carb-loaded foods that pack on the kilograms.

Chronic poor sleep comes with big risks: Heart disease, type 2 diabetes, stroke, high blood pressure, depression and anxiety among them.

“We’re increasingly finding across all of our research, and across the lifespan, that when people aren’t achieving decent sleep, that has implications for their waking life,” Massey University sleep researcher Dr Rosie Gibson said.

“That plays out with physical as well as psychological consequences: in our ageing population, for instance, we see an earlier need for care.”

Want to sleep well? Be wealthy

Kiwis living in deprivation fare worse on most health indicators – and sleep is no exception.

Ministry of Health data tells us fewer than two-thirds of adults living in our poorest areas are getting the recommended amount of sleep, compared with nearly three-quarters in the wealthiest.

It also shows poorer sleep among Māori and Pacific people – and fewer than half of all disabled Kiwis get enough sleep.

“We think there’s lots of systemic drivers at play,” said Dr Karyn O’Keeffe, a senior lecturer at Massey University’s Sleep/Wake Research Centre.

“And it’s not just your individual things that we often think about, like caffeine and alcohol, but the type of work people are required to do, family commitments and dynamics, and sleeping environments.”

One 2021 study, for instance, found half of our children may be sleeping in rooms that are too cold in winter and humid in summer – with disadvantaged kids most at risk.

“If people don’t have autonomy over when, how or with whom they’re sleeping, that’s going to mean they can’t necessarily get a good night’s sleep,” Gibson said.

It’s bad news when kids don’t sleep

Increasingly, scientists are finding sleep couldn’t be more important for our very youngest.

Among babies and toddlers, it’s vital for everything – from growth, body mass and motor skill development to learning and memory – all the building blocks that give us a strong start to life.

Toddlers need much more shut-eye than we adults – 11 to 14 hours per day – while pre-schoolers require about 10 to 13 hours.

Yet, according to New Zealand’s largest study of its kind to date, one-third of toddlers – and a fifth of pre-schoolers – aren’t getting enough.

Material hardship was singled out as a big factor – particularly in urban environments with lots of noise, light and heavy traffic

And another culprit was the overuse use of TV and tablet devices.

Researchers recently found links between persistent poor sleep in the first year of life and a higher risk of developing anxieties and emotional disorders later in childhood.

And last year, a University of Otago study revealed how children eat differently when they sleep less – with as little as 40 minutes a night less we’re seeing increases in energy intake and decreases in diet quality.

Let your teens oversleep

As any parent of teenagers knows, they like to rise late – but it’s not just preference, it’s biological.

When we hit puberty, our sleep patterns change to favour later bedtimes – a shift that lasts until age 21, and one that means waking a teen at 7am is similar to waking an adult at 4am.

Because of these different habits, researchers recently argued that delaying school starts until 9.45am should be a “no brainer” – but few schools have made the shift.

Around half of our teens don’t get enough sleep, or get poor-quality sleep – both linked with poorer mental health, attendance rates and academic performance.

That’s not just because of waking too early. It’s also influenced by a mix of factors including after-school activities, homework – and electronic devices.

New parents – no sleep? No problem!

Having a new addition in the home can bring an onslaught of fatigue and sleep deprivation.

Yes, that constant tiredness can leave us drowsy, irritable, injury-prone and at higher risk of depression.

If we’ve been up half the night rocking a baby, we can expect more day-time mind-blanks: effectively “micro-sleeps” stemming from a build-up of neurochemicals that promote sleepiness.

That leads us to every new parent’s saviour: The double-shot espresso. On average, caffeine has a half-life (the time it takes for your body to eliminate half the drug) of three to five hours, although effects can last up to 14 hours.

Limited to that one blessed cup of coffee in the morning, it’ll be gone from your body by bedtime. But overdo the coffee throughout the day, you might stave off tiredness but you may also have trouble falling asleep later.

But there is some good news for sleep-deprived parents. Research suggests our brains can adjust to moderate sleep loss, stabilising at a lower level of cognitive performance without long-term impacts. Billions of humans have been through it all before us, after all.

Experts recommend catching up on extra sleep at the weekend where possible – like paying off a credit card in overdraft.

“So, our brains will try to help us as much as they can,” O’Keeffe said. “Our understanding is that it’s when this is happening on a long-term basis that we see the highest risk of developing health conditions.”

Your sleep will change with your age

As we get older, our sleeping habits shift again.

“Areas of the brain responsible for sleep start to deteriorate as we get older, so the depth, quality and timing of sleep we get can change,” Gibson said.

Older people are more likely to wake in the night, or nap during the day.

“We also see an increase in sleep disorders like insomnia and sleep-disordered breathing.”

On top of that, social changes – retiring, downsizing or experiencing bereavement – also take a toll.

Older people might be caring for loved ones with conditions like dementia, or living with chronic health conditions, or sleep-disrupting side effects of medications.

Gibson said ageing people can be quite accepting when their sleep gets worse.

“People don’t necessarily problematise it so much.”

Don’t doom-scroll before bed

The shortwave blue light beamed out from our smartphones isn’t good for getting to sleep, because the cells behind our eyeballs tell our brain it’s morning.

That postpones the release of the sleep-promoting hormone melatonin.

But browsing social media in bed is even more disruptive than that: it stimulates the brain and delays REM (rapid eye movement) sleep, especially if we’re “doom-scrolling” through troubling news headlines or enjoying that repeated notification ping.

In contrast, watching a gentle television show or listening to music on your phone hinders sleep much less.

“From a physiological perspective,” O’Keeffe said, “holding something close to your face is going to have much more of an impact than watching a TV a couple of metres from you.”

Develop a health scepticism for sleep aids

Visit the App Store and you’ll find endless tech solutions to train your brain for sleep.

Not to mention a galaxy of sleep-tracking smart watches, smart rings, bedtime headbands, hand-held sleep aids, Bluetooth eye masks, luxury mattresses, timed lights, and dicey “wellness” cures for insomnia.

Sleep is a booming multibillion-dollar industry.

“We’re self-quantifying our sleep, and a lot of these devices we’re using to do it aren’t necessarily validated,” Gibson said.

Many of the companies behind them don’t share their algorithms so researchers can’t compare them against gold-standard measures. Maybe that’s the point.

And paradoxically, gathering too much data about our sleep can increase worry. Sleep anxiety is a real problem – that creates the very problem we’re trying to solve.

“If our watch tells us that we didn’t sleep well, do we then feel more tired, as a placebo during the day?” Gibson said.

“It’s an interesting time.”

Old myths die hard

Ever heard people obsess over getting their eight straight hours of shut-eye?

“That’s a big myth because different people have different sleep requirements,” psychiatrist and sleep specialist Dr Tony Fernando said.

“There are people who feel refreshed with six or seven hours, but get headaches when they get eight, and then there are those who need nine or 10.”

Ministry guidelines recommended eight to 10, seven to nine and seven to eight hours for people aged 15 to 17, 18 to 64, and older than 65, respectively.

“Eight might work for the majority of people, but not everyone.”

Gibson agreed.

“The idea of waking up in the night is something that we’ve made a problem and aligns with trying to get eight hours of consolidated sleep so we can all go to work for eight hours,” she said.

“We see a pattern in older people where they might have two or three chunks of sleep across the night, and maybe an afternoon nap: It doesn’t have to happen in one eight-hour block.”

Fernando said it wasn’t a “disaster” to wake in the night, “so long as you’re relaxed and can fall back asleep relatively quickly”.

Advice varied from making a cup of tea, to reaching for a book, to meditating.

“How people relate to that recommendation can make or break their sleep, and it all depends on how relaxed you feel,” he said.

“If meditation makes you feel stressed, it’s the wrong activity; but if watching a horror movie on Netflix is relaxing, then do it.”

We don’t have all the answers

As an Auckland-based clinician, Fernando has seen many people with sleep problems.

Among the quarter of Kiwis living with chronic sleep problems, insomnia stands out as among the worst – and there’s still no magic treatment for it.

“There are psychological treatments, potions and tablets, but we don’t have anything perfect.”

O’Keeffe pointed to five principles developed by Oxford University neuroscientist Dr Colin Espie: To value, prioritise, personalise, trust and protect your sleep.

“Everyone’s going to have some bad nights, but know that your brain’s got some really good mechanisms to promote sleep – and if it doesn’t go well one night, then it probably will come right in a couple of days’ time.”

*To mark World Sleep Day, on March 15, the New Zealand branch of the Australasian Sleep Association will be hosting a webinar by Christchurch sleep surgeon and NZ Medical Council chair Dr Rachelle Love.