Sleep is a basic human need. In this episode, we will be talking about sleep systems, age-related changes in sleep patterns, myths about sleep, various sleep disorders (including sleep apnea and insomnia) and cognitive-behavioural therapy as a common treatment for insomnia. Our guest, Sasha Usyatynsky, is a PhD student in clinical psychology at Ryerson University. She shares a lot of amazing insights about sleep and the aging brain, as well as tangible tips you can use to ensure you are getting the sleep that your body and your brain needs.

Sleep Regulation Systems

There are two systems that work in tandem to regulate normal sleep (circadian rhythm and sleep drive) and a third system that can interfere with them (anxiety).

1. Circadian Rhythm

The first system is your circadian rhythm. You can think of it as your internal body clock and it regulates a whole number of things in our body – for example, like when your brain sends alerting signals for you to be wakeful, when you get hungry, when your body temperature fluctuates throughout the day (e.g., your body temperature gets lower at night). The tricky part is that your internal body clock works on – close to – a 24-hour schedule, but it’s not actually quite 24-hours (it’s a bit more than that); so, it is constantly getting out of sync with the clock on the wall (which is strictly 24-hours). What you need to do is match up our circadian rhythm to the clock on the wall (as best we can, so that you're able to feel like your “best self” during the day. You can do that by:

• Keeping a regular schedule

• Eating meals around the same time every day

• Getting exercise or socializing around the same time every day

• Getting up and out of bed; and getting some light exposure early in the morning, but consistently at the same time every morning

NOTE - your body does not know the difference between a weekend and weekdays; so, if you go to bed late and sleep in on the weekend, this can actually create some problems with your circadian rhythm and give you a jet lag syndrome (where there is a mismatch between your circadian rhythm and the clock on the wall).

Regularity is key for the circadian rhythm.

2. Sleep Drive

Now the second sleep system that operates is the lesser known sleep drive. The sleep drive is your need for sleep at any given point throughout the day. When you first wake up, your sleep drive will be pretty low, since you just spent it on sleep for the night. But, as soon as you get out of bed, and your feet hit the floor your sleep drive starts to build. The more active you are throughout a 24-hour period, the faster and higher your sleep drive will build. So, when it gets close to your bedtime, you’ll have (hopefully) built up enough sleep drive to give yourself some good quality sleep. It is akin to having a good sleep appetite. Note – having a high sleep drive does not mean that you'll sleep for a long time necessarily, it has more to do with the quality of sleep that you will get. With a high sleep drive, you’ll likely fall asleep quicker; but, mostly, it will give you more deep sleep, which is when your body produces the hormones that you need to feel refreshed the next day.

Basically, these two sleep systems work together: your circadian rhythm is strong and set, and – in addition - you're building up your sleep drive during the day by being active. In this way, you're going to have a good 24-hour period of healthy wakefulness and sleep.

3. Anxiety

The third system that interferes with your circadian rhythm and your sleep drive is anxiety. Humans evolved to prioritize survival. Back during the time of our ancestors, if we were really sleepy – but, then a bear appeared, our bodies would kick us into “fight or flight” and override your sleepiness. Of course, in present day, we are not likely fighting off bears, but you tend to feel anxiety about other things. The “bear” becomes worry about your day. So, if you’re feeling anxious, it is important to get out of bed, because you won’t likely fall asleep if you’re feeling anxious.

Sleep patterns change with the age

There is a lot of correlation research that shows that sleep quality goes down with increasing age. In other words, aging is associated with poorer quality of sleep. But it isn’t an inevitability. It may have to do with some contextual issues. So, if you think about what happens as you age, your need for sleep (which is largely biologically determined) doesn't really change. So, if you were a 7-hour sleeper when you were an adult, you don't suddenly become a 5-hour sleeper or a 9-hour sleeper (for example), when you turn 65. Your body's natural need for sleep isn't going to go up as you age (in the absence of other sleep disorders). But, what sometimes happens as people age is that they reduce their activity level. They become less physically active, less socially active – which, in some cases, can be linked to the experience of developing pain, as you age. Based on what we know about sleep drive, as your activity levels go down, your time spent in bed should also – logically – go down. But, what actually ends up happening is that people end up spending even more time in bed as they get older (e.g., if they nap or try to get more “rest” because they think they need it). So, essentially, people are trying to use their 7-hours of sleep drive into a 9-hour window. In other words, you’re stretching good quality sleep into poor quality sleep by trying to fit it into a longer sleep window. As a result, you're probably going to experience a worse quality sleep and probably more wakefulness in the middle of the night. Often times, the quality of people’s sleep goes down when they age because they’re not accounting for changes in their lifestyle.

One biological change that actually starts happening, when you get older is that your eyes start changing and light information doesn’t get in as much, which impacts your circadian rhythm. As such, it might be beneficial to spend more time outside, and getting more light exposure, as you age. Some sleeping tips:

·       Spend more time outside (to increase light exposure)

·       Be active and moving around during the day (exercise and socialize at consistent times)

·       Keep a regular schedule (regular meal times, consistent rise and sleep times)

Myths about sleep

Sleep Myth #1: Golden number eight

A big myth is that there is a golden number of hours we need to sleep to feel good the next day. This myth is largely perpetuated by the media and is actually not accurate, because everyone has a different need for sleep. The belief that you need to sleep for seven or eight hours a night might create unrealistic expectations for people, if they are not a 7- or 8-hour sleeper. So, when people don't meet these expectations, because you can't sleep that much, you'll get anxious about your sleep, which will interfere with your ability to sleep for the amount of time that you do need. Some people need 3-hours of sleep and feel totally fine, while other people need 10-hours of sleep to feel totally fine; but, most people do fall within the 6-8 hour range, but any individual might be outside of that. The key is to just listen to your body.

Sleep Myth #2: Quality sleep is solid, with no waking periods

Another myth is that you're supposed to sleep without waking throughout the night. That's actually not true – our brain wakes up on average 12 times an hour in the middle of the night; however, it is not true awakening. Individuals do, however, generally wake up a couple of times a night (e.g., turning over and immediately falling back asleep, getting up and going to the bathroom and then coming back to bed, etc.). If your waking periods are not longer than 5-minutes, then it is completely normal. Normal waking periods typically happen in the second half of the night. An issue would be if your wakefulness is for long periods of time and you cannot get back to sleep. But, it is completely unrealistic to think that you should fall asleep once and not wake up at all until you get out of bed in the morning.

Sleep Myth #3: You can control your sleep

Our body takes care of us getting the sleep that we need. Much like we don’t force our heart to beat or force our lungs to breathe, we do not need to force our bodies to fall asleep. Trying to sleep actually creates a paradoxical effect, whereby the more you try to sleep, the further away it gets.

Falling asleep is like falling in love – it is a mess when you try to force it.

The solution is to have confidence in your body. Trust that your body knows what it needs, and just listen to it. If you're not sleepy, don't go to bed. If your body wakes up, and is fully awake, then you should get out of bed and start your day.

Shifting your sleep window

You can definitely re-train your body and shift your sleep window. The anchor point for that is actually your rise time. Getting into bed earlier does not guarantee that you will fall asleep any earlier. The key to shifting to an earlier bedtime is shifting to an earlier rise time.

Sleep and your brain health

A lot of research has been coming out recently that is highlighting the importance of sleep on your brain health. For example, some research has shown a link between sleep disruptions and changes to the structure of the brain. A 2019 review article (Zhong et al., 2019) that talks about the relationship between sleep and brain changes as being bi-directional. In other words, age-related brain changes lead to sleep difficulties, but also sleep disruptions can accelerate the rate at which the brain undergoes age-related changes.

There have also been a lot of correlation studies that demonstrate that chronic poor sleep quality is associated with a whole number of issues – e.g., depression, high blood pressure, and dementia (for example).

One likely contributor of driving sleep challenges is obstructive sleep apnea.  

Obstructive sleep apnea

Obstructive sleep apnea is a sleep disorder that is more common in the elderly. In other words, as people age, their likelihood of developing obstructive sleep apnea increases. A recent study from the European Respiratory Journal in 2018 talk about this issue. Specifically, obstructive sleep apnea leads to breathing interruptions in your sleep. When you have so many breathing interruptions while sleeping, it reduces the levels of oxygen in your blood. According to the 2018 research from the European Respiratory Journal, this drop in oxygen may actually be linked to a shrinking of the brain's temporal lobes (which houses the hippocampus – your brain’s memory centre) and a corresponding decline in memory. So, in fact, sleep apnea may be driving a lot of age-related changes in your brain. Since obstructive sleep apnea affects the brain’s memory structure, it has been shown to impact dementia. The authors of this research strongly suggest that screening older adults for sleep apnea, and giving them treatment when it is needed, may help prevent dementia in older adults. Approximately 35% of the risk of dementia is associated with modifiable factors, such as depression, high blood pressure, obesity as well as smoking, and now sleep apnea is coming out as another modifiable risk factor of dementia.

Indicators of sleep apnea

1. Loud snoring

2. Feeling sleepy during the day

3. High blood pressure 

4. Someone actually observing you stopping breathing in your sleep or choking, gasping for air during sleep.

If you are experiencing even one of the above symptoms, but typically when people experience two or more symptoms, then it is definitely recommended that you talk to your physician about being assessed for sleep apnea.

Sleep apnea is notoriously under diagnosed in slim women, because sleep apnea is associated with a higher body mass index (BMI), and is more prevalent in older males. As such, if you are someone who is experiencing sleep apnea related symptoms, it doesn't matter what your body mass index is or if you're a woman or not, you should really advocate for yourself with your doctor - especially if you are  a slim woman, but you are experiencing some of these symptoms.

Getting diagnosed with sleep apnea

The process of getting diagnosed with sleep apnea involves doing a sleep study. First, your doctor would ask you a couple of questions to review some of the indicators that someone might have sleep apnea, and then – if it was a serious concern – your doctor would refer you to do a sleep study. In a sleep study, you would go to a sleep centre and do an overnight sleep study. During the sleep study, you would be hooked up to a variety of machines and your sleep would be monitored throughout the night. If sleep apnea was diagnosed, you would be walked through the treatment for that (e.g., Continuous positive airway pressure [CPAP] device).

What is insomnia?

Insomnia disorder is a chronic sleep problem. It is defined as a difficulty with falling asleep or staying asleep throughout the night, waking up too early or any combination of these problems. For a diagnosis of insomnia, you have to be experiencing these difficulties at least three nights per week, for at least 3-months or longer. The defining feature of insomnia is that it causes significant distress or impairment in functioning for the person. In other words, someone might be experiencing sleep difficulties, but if they’re not concerned, it wouldn’t be a clinical issue.

The 3P Model of Insomnia

The 3P Model is one of the biggest in the field right now. The first P stands for “predisposing” factors. Some people are just inherently more likely to develop insomnia. For example, people who are more anxious or have a more active sleep system. The second P stands for “precipitating” factor. Often, some life event triggers transitory or a brief bout of insomnia. For example, work stress, going through a divorce, having an illness (yourself or a loved one), having a new baby, construction outside your window – basically, anything that gives you brief sleep problems. But, when the event passes, the insomnia usually goes away for most people. The last P stands for “perpetuating” factors that makes a potentially brief insomnia into a chronic problem. “Perpetuating” factors are typically behaviours that people do – e.g., taking naps, or thoughts about your sleep (like excessive daytime worry about your sleep) that people adopt in order to cope with sleeplessness. While people are just trying to make things better, due to a lack of knowledge about the sleep system, what they are really doing is interfering with the two sleep systems that regulate sleep (circadian rhythm and sleep drive) and they amp up anxiety. So, they end up maintaining insomnia in the long run. Treatment for insomnia is actually focused on changing those behaviours and beliefs.

What is the connection between insomnia and depression?

Insomnia and depression are definitely linked. Insomnia is oftentimes a symptom of depression. Sometimes, treating depression means that the symptom of insomnia will go away. But, often times, insomnia and depression are both problems in their own right. There used to be a distinction between primary and secondary insomnia – but that is no longer part of the diagnosis. Now it's just insomnia. Basically, treating depression only - without treating an insomnia problem that warrants its own treatment (because it is clinically significant) can be problematic. Research shows that if you're treating just the depression – sometimes the insomnia doesn’t go away, even if the depression goes away. And the presence of insomnia puts individuals at a higher risk of relapse for depression. Likewise, insomnia can be difficult to treat in very severely depressed individuals. In cases like this, you want to take a two-pronged approach: You want to treat the depression and you want to treat insomnia, if the insomnia is severe enough.

Treating Insomnia

Cognitive-behavioural therapy or CBT is the gold-standard and most recommended approach when it come to the treatment of insomnia. In general, CBT is based on a theory that our thoughts, our behaviours and our emotions are linked and act on each other. In the case of insomnia, it’s not just emotions, it is also your sleep that is being impacted by your behaviours and your thoughts. CBT for insomnia is really focused on helping the person get out of their body’s way, because your body knows what to do and we want to reduce behaviours and thoughts that get in our body’s way when it comes to getting sleep.

Sample: Four session brief CBT for insomnia.

In Sasha’s lab, they use a four-session brief CBT for insomnia, and they have a 82% remission rate (82% of people, after 4-sessions of CBT for insomnia, are no longer experiencing symptoms of insomnia). In Sasha’s lab, the effects of CBT for insomnia are shown to be maintained for at least 1-year. Interestingly, research has demonstrated that CBT for insomnia is effective in treating depression as well.

1. Build your sleep drive – e.g., by (a) getting out of bed as soon as you wake up (or within 5- to 15-minutes, (b) being active during the day (socially and physically) and (c) avoiding being inactive during the day.

2. Have a good strong circadian rhythm – e.g., by (a) regularizing your activity, (b) getting light exposure in the morning by getting outside for even a brief walk.

3. Do not associate your bed with wakefulness. Try to reduce the amount of wakeful time you spend in bed. So, if you have trouble falling asleep in general, it is important that you take all wakeful activity outside of your bed (e.g., reading, watching TV). When you can’t sleep – get up and out of bed, and only get back into bed when you are truly sleepy again.

4. Give yourself a wind-down period before you get into bed. Allow yourself time to process the day ahead of bedtime, so that you do not spend your time in bed thinking about the day. Find a mindless activity to do before bed that will allow your mind time to wander (e.g., doing the dishes).

Other sleep diagnoses

Some other sleep diagnoses, include:

1. Restless Leg Syndrome or Periodic Leg Movement Disorder

2. Circadian Rhythm Disorder

Restless Leg and Periodic Limb Movement Disorder is when people find their legs are moving or twitching repeatedly when they sleep. If you are noticing these issues yourself then you want to talk to your doctor about this condition, because it makes for the less restful sleep and increased sleepiness during the day.

The main symptom of Circadian Rhythm Disorder is a delayed or advanced sleep phase. So, this is when your sleep window is shifted by multiple hours from what is normal. Basically, this is seen in people who are extreme night owls or extreme early birds. But otherwise, their sleep is normal within those shifted hours. The main problem for individuals with Circadian Rhythm Disorder is that their body wants to function on a schedule that's not normal within our society. There are treatments for this – you just have to talk to your doctor.

 About the Sleep and Depression Lab at Ryerson University

To find out more about the research taking place at the Sleep and Depression Lab at Ryerson University, you can visit their website by clicking here, email their lab coordinator Olya (olya@ryerson.ca) or you can call the lab 416-979-5000 ext. 2185.

Upcoming research

One of the upcoming studies at the Sleep and Depression Lab will involve providing CBT for insomnia. Of course, not everyone will be eligible to participate (because there is specific criteria), but they have a lot of resources available at the lab; so, please feel free to reach out to them if you have any specific questions.