Now, recent research from Michigan State University suggests science may have underestimated the negative effect that lack of sleep has on our cognitive function. It makes us particularly poor at completing any activity that follows multiple steps – whether you’re a doctor operating on a patient or someone operating a vehicle.
Sleep specialist Alex Bartle says many people make the mistake of focussing on the amount of sleep they are getting, when quality is equally important.
“They’ll say they don’t understand why they’re so tired during the day when they’re sleeping for eight or nine hours a night.”
Bartle is the director of a national network of Sleep Well Clinics in New Zealand and says up to 60% of the people treated there have obstructive sleep apnoea. This means the muscles of the throat become too relaxed during deep sleep and part of the airway is closed off, so they repeatedly semi-wake as they struggle to breathe. It can happen hundreds of times a night, although the person may not be aware of it, and being overweight, drinking alcohol or taking sleeping pills increases the risk. For many, the solution is to wear a device called a CPAP (continuous positive airways pressure), which keeps the airway open during sleep.
“When it’s set up correctly, it’s a fantastic treatment,” says Bartle. “We get two or three people a week who say it’s changed their lives. Their blood pressure comes down, their cognition improves.”
For the 40 to 50% of their patients who complain of insomnia, technology isn’t the answer. When all the usual sleep-hygiene tips – no screens, a cool, dark room, a regular routine – don’t work, people can start to lose confidence that they are capable of a good night’s rest, and bed becomes an anxious place.
Bartle says that rather than going to bed early, then tossing and turning, people should restrict their sleep. Patients are told to work out how long they think they are sleeping and restrict their time in bed to that amount – but no less than five hours.
“So, you’re not allowed to go to bed until midnight and you have to get up at 5am,” he explains. “It seems counterintuitive, as people will say they want more sleep, not less, but it improves sleep efficiency. And gradually you can increase your time in bed.”
Another key is getting outdoors every morning so you wake up properly. Light suppresses the sleep hormone melatonin and triggers the release of the good-mood hormone serotonin. This happens when it hits your eyes, so wearing sunglasses will block the effect.
If you are lying awake and feeling anxious at night, it is better to get up, but only for 15 minutes, advises Bartle, and that time should be focused on calming the mind with meditation or by journaling (writing down worries and feelings).
Often, something like a new baby or a really stressful job can establish a pattern of not sleeping and the longer it goes on, the harder it is to change.
“The Canterbury earthquake triggered sleep problems for many people and nine years later some continue to have difficulty,” says Bartle.
The latest research from Michigan found that sleep deprivation doubles the chance of making placekeeping errors (repeating or skipping steps in a task that involves many sequential steps) and triples the number of lapses of attention. Bartle says there are lots more studies to prove that behavioural strategies are more effective in the long term than relying on medication for a restful night.
“We can all sleep,” he promises. “It’s just getting the body to do it again.”
This article was first published in the January 18, 2020 issue of the New Zealand Listener.