Surprising secrets for a better night's sleep (and better health)
UQ Mythbusters
We all know how important a good night’s shuteye is for us – but how much misinformation have you been sleeping on when it comes to how to get a proper night’s rest, and the impact that a poor sleep can have on your health?
UQ Mythbusters is back and here to help you separate fact from fiction with the help of sleep science expert Professor Bruno van Swinderen from the Queensland Brain Institute (QBI).
Key points:
- Your smart watch may be misleading you on the quality of your sleep.
- A lack of consistent healthy sleep might limit your ability to maintain healthy brain cells.
- Even a single night of poor sleep impacts your reflexive behaviours.
- Looking at your phone in bed will convince your brain that it’s not time to sleep.
- You can use conditioning to train your brain for better sleep.
Q: What are some of the most prevalent myths surrounding sleep and sleep science that you think need to be busted asap?
A: Many people seem confused about the meaning of ‘quality sleep’, as if it’s just the low valleys that can be tracked on a smart watch. They obsess about getting enough ‘deep’ sleep. But sleep is not just one thing. It’s characterised by distinct stages that alternate through the night. Quality sleep means getting a normal dose of those alternating sleep stages, including the rapid-eye-movement (REM) stage that is associated with vivid dreams. Most current insomnia drugs don’t deliver that – they promote deep sleep only. This is not ideal.
Q: Can you ‘catch up’ on sleep? That is, if you sleep poorly during the week but sleep in on the weekend, does that counteract any harm done to your health?
A: Experiencing a sleep rebound to make up for lost sleep is actually one of the defining characteristics of sleep. It’s what’s called a homeostatic process. Your muscles don’t need to rest proportionally to how much you exercise. But your brain tries to catch up on all of your lost sleep.
One potential problem is that the sleep-deprived brain seems to want to prioritise some sleep functions over others, such as those associated with maintaining healthy brain cells. But you might be missing out a bit on other sleep functions, such as those associated with memory or emotion regulation.
Q: How does a poor night’s sleep impact your cognitive function and attention during the day?
A: Everyone who has had a bad night’s sleep knows this is true from a subjective point of view: your capacity to pay attention is impaired. What we also know from scientific experiments on humans and other animals (even fruit flies) is that a single night of sleep deprivation makes it harder to suppress reflexive behaviours, such as responses to motion or bright lights or visual clutter. This is why walking through the luxury shopping nightmare that is Dubai International Airport is so unbearable for middle-aged Australians like me.
Professor Bruno van Swinderen
Professor Bruno van Swinderen
Q: Why do so many of us find ourselves awake at 3am thinking about all the mistakes we’ve ever made? What should we do when that happens?
A: It’s an age thing. We alternate sleep stages about every 90 minutes throughout the night, and these alternations are often accompanied by brief awakenings. Around 3am might be after our second deep sleep cycle. As you get older, thoughts intrude and worry prevents a normal return to sleep. This is one of the prices we pay for being human and accumulating stories in our head. I don’t think other animals suffer from this problem. Focussing your attention to your breathing rather than your mistakes can help.
Q: Many people use white noise, podcasts or other sleep aids to help them nod off. Is there any harm in this?
A: Effective sleep habits are about conditioning yourself, like Pavlov’s dogs. The cup of herbal tea before bed is more about the behavioural association with sleep than anything really in that hot water.
Similarly, white noise or podcasts can become conditioned prequels to sleep, irrespective of the content. I suppose there is a potential concern that too much value gets attached to these rituals, such that anxiety creeps in if they are missed. Insomnia is mostly an anxiety problem.
Q: Is it true that looking at the blue light from our phones before sleep can have an impact on our sleep?
A: This is true. We (and other animals) have blue light receptors in our brains that promote wakefulness. This is because we have evolved in a world where more blue light signals that it’s daytime, and in diurnal animals there is a strong ‘circadian’ drive to over-ride sleep need if it’s daytime.
So, if you have significant blue light exposure before sleep you are essentially tricking your brain into thinking that it isn’t time to sleep yet. Indeed, some researchers are looking into exploiting this blue-light strategy to reset your sleep cycles to help with jetlag or shift work.
Q: Do some people need less sleep than others, or is there a universal ‘healthy’ amount of sleep?
A: Here’s my most important message: a healthy brain knows how much sleep it needs, and what kind of sleep it needs. Even an unhealthy brain knows what kind of sleep it needs, which is why we often sleep more when we’re sick. It’s a self-regulating machine.
For the most part, we need to stop worrying about getting enough sleep and just let it do its job. That said, modern society does make it harder to let sleep do its job, with all the artificial lighting and phones dinging on the bedside table.
Q: What do we know about the long-term health implications of poor sleep habits?
A: Every human cognitive disorder seems to be associated with sleep problems, so it follows that poor sleep habits might be causal to some of these, including Alzheimer’s disease and schizophrenia for example.
It’s important to disambiguate the potential functions achieved by different kinds of sleep, to better understand health impacts. Deep sleep might help repair the brain. But what does insufficient REM sleep cause? This remains unclear but is probably just as important for a healthy life.
Does it matter what time I go bed?
Some of us love to be tucked up in bed by a particular time every night, ensuring a certain number of hours of sleep. Others go to bed when they start to feel tired, or when they’ve finally finished everything they wanted to get done, and get up when they need to in the morning. But does it matter what time you go to bed?
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