Ontario Brain Institute: The science of better sleep

TVO.org speaks with neurologist Andrew Lim about the connection between sleep and health — and why so many people are finding it hard to get a good night’s rest during the pandemic
By Daniel Kitts - Published on Mar 09, 2021
Andrew Lim is a member of Ontario Brain Institute’s neurodegenerative-diseases research program. (Doug Nicholson/Sunnybrook)



Sleep is something you’d think we would understand better since it’s something pretty much all of us do every day.

But what happens when we sleep — and how sleep affects our health — is still being explored by researchers.

On Wednesday at 6:30 p.m., the Ontario Brain Institute will host an online talk about sleep and brain health. An expert panel of scientists and advocates will discuss the latest research into sleep, its impact on brain health across our lives, and practical tips to help us all get a better night’s rest.

One of the panel participants is Andrew Lim, a member of the institute’s neurodegenerative-diseases research program and a neurologist at Sunnybrook Health Sciences Centre, in Toronto. TVO.org speaks with him about why so many of us find it hard to get enough rest, how the pandemic is affecting our sleep, and the connection between sleep and neurodegenerative conditions, such as Alzheimer’s disease.

TVO.org: Humans spend roughly one-third of their life sleeping. It's something we've been doing since humans first existed. So why are so many of us so bad at it?

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Andrew Lim: I think it's a mix of things. Some of it probably has to do with massive changes in our sleep environment and living environment between the time that we evolved on the African savanna to modern life. We have a lot more in terms of artificial lights, and we have stresses and anxieties that probably didn't exist back then. In large probability, we lead, to some degree, more unhealthy lifestyles with a lot less physical activity. The other thing is that there are people who have sleep disorders and other things like that as well.

TVO.org: We're hearing anecdotally that people are having more trouble sleeping during the pandemic. In fact, some of my colleagues have said they're experiencing issues. Is that showing up in any research?

Lim: It's a mixed bag. Anecdotally, I see both: I see people who've had a worsening of sleep because of the pandemic, and I've actually seen people who’ve had an improvement in sleep. The improvers are folks who maybe before the pandemic had to wake up outrageously early in order to commute for hours to get to work. On the other hand, there are patients I've seen who have had worse sleep. I think one important contributor to that is a loss of routine. Your routine is a big part of healthy sleep habits. You're getting out in the morning, you're walking to the subway, or you're driving out in the sunlight. It’s an important time signal for your biological clock. Also, people aren't exercising as much. It's hard to get exercise under pandemic restrictions, and that contributes to worsening sleep. And, then, of course, there's a certain degree of anxiety that just permeates the pandemic: Anxiety about health. Anxiety about finances. And that anxiety can lead to poor sleep.

TVO.org: Your work involves studying the impact of sleep on cognitive decline, dementia, and neurodegenerative diseases. What links are you finding between a lack of sleep and these conditions?

Lim: In epidemiological studies that take a look at folks with good or poor sleep and a subsequent risk of developing cognitive impairment, it appears as though several different forms of poor sleep, such as sleep apnea, are associated with higher future risk of developing dementia.

The question, of course, is why. In some cases, it could be that poor sleep is an early feature of changes already occurring in the brain that are related to dementia. For instance, people who develop Alzheimer's disease begin to accumulate changes in the brain years before the onset of memory complaints. And some of those brain changes may be leading to sleep difficulties. But, at the same time, there's increasing evidence that sleep plays an important role in maintaining brain health. And so poor sleep may be contributing to the risk of dementia.

TVO.org: What can be done about that?

Lim: The first thing is that there are many things we can do ourselves, without any sort of medical testing or intervention, to improve our sleep. Things like making sure you have regular sleep habits, a regular routine in general, enough physical activity  — all those things that we should be doing anyway. And making sure we schedule enough time to get the sleep that we need. A rule of thumb is that if you need the alarm clock to wake up in the morning, you're probably not getting enough sleep.

And we need to value sleep to some degree more as a society. There's a certain strain out there that almost puts pride in depriving yourself of sleep in order to work more. And that probably isn't a healthy way of looking at sleep. And, then, if you're getting enough opportunity for sleep, enough physical activity, and a good bedtime routine and you still find yourself unable to sleep, having difficulty sleeping, or feeling excessively sleepy during the day, do not accept that as being a normal state. At that point, maybe consider speaking to a doctor about that, because there may be an underlying sleep disorder.

The three take-home messages are that sleep is important for the brain, that there's a wide range of normal, proper sleep — but that, at the same time, we shouldn't be satisfied with unsatisfactory sleep.

This interview has been condensed and edited for length and clarity.

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