A Guide to HRV: The Impact of Sleep

In this video we're going to be talking about sleep, how it can become dysfunctional in complex chronic illness, how it can affect elements of autonomic health such as heart rate variability, and then some tips and tricks that we can use to improve sleep, and thereby overall health, in complex chronic illness.

Sleep is an incredibly restorative process for the body and the mind. When we go to sleep, what typically happens is our autonomic nervous system will shift its activity from fight-flight, or sympathetic nervous system activity, over to parasympathetic nervous system activity, or rest and digest.

People with complex chronic illness often experience difficulty going to sleep because of dysautonomia, or autonomic nervous system dysfunction. This is usually because their fight-flight system is in overdrive, and it leads them to an experience of feeling what's called "tired and wired". They're very tired from the day's exertion, but their autonomic nervous system is still telling them that they're under threat and they're experiencing a lot of stress, and that can make it very, very difficult to fall asleep.

We often see changes in autonomic nervous system function, so people will have more sympathetic or fight-flight nervous system activity going on, which causes disruption to all phases of sleep and increases the likelihood that you're going to experience sleep disruptions and multiple wakeful events through the night. We also see hormonal dysfunction in people with complex chronic illness.

When we're thinking about high-quality sleep, there are a few factors that we really want to focus on: sleep length, sleep depth, and sleep consistency.

When it comes to sleep length, what we're really trying to do is make sure that the body is fully prepared to enter into a sleep state and stay asleep for as long as the body needs. This can start from the very first moment that you wake up from the previous night's sleep — making sure that you're getting adequate morning light that triggers your body into understanding that the day is beginning. It helps hormone cycling start to occur in a healthy fashion. Then, as you go through the day, make sure you're doing things like not eating too late at night, and that you don't do anything too stressful or exertional just before bed. It's okay to do things that are cognitively taxing, but not within two to three hours of sleep, because that can push you into a state where you're going to have difficulty staying asleep for a long period of time. It's very important that you're getting at least seven to nine hours of sleep per night, so that you can get as much restorative sleep as possible for your physical body as well as your cognitive health.

As we move into how to maximize sleep depth, it's about making sure that your autonomic nervous system is ready for sleep. We've spoken about fight-flight and its ability to impact sleep. When you're going to sleep, if you want to ensure deep, uninterrupted sleep, things like breathwork that can help to switch the body from a fight-flight situation to rest and digest can be really helpful in encouraging deep sleep.

When you're optimizing sleep consistency, this is one of those things where it can really benefit you to be quite militant about your habits. It's unpleasant — no one likes having a bedtime — but doing your best to keep your bedtime consistent within a half-hour range is something that will be really helpful in ensuring sleep consistency. Use what's happening outside to guide the light cues that you give yourself: have light coming primarily from the ceiling in the morning, to mimic what the sun is doing, and light coming primarily from lower down, like lamps, as opposed to overhead lights in the evening, to mimic the sun going down. These things are going to be really powerful in triggering circadian rhythms that help your body get into this highly consistent sleep mode.

We can group sleep into non-restorative sleep and restorative sleep. Both are important, and you can't get one without the other, but restorative sleep is the part of your sleep where you actually experience physical recovery from the day's exertion, as well as cognitive recovery. When you have a deficit in restorative sleep, what we've seen in the literature is that the next day your fight-flight nervous system activity is going to be heightened, which means that your heart rate variability is going to drop. By contrast, if you're able to get a good, deep night's sleep where you maximize restorative sleep time, your nervous system is going to shift more to rest and digest during the day, heart rate variability will increase, and you'll typically have a much better day symptom-wise.

So to recap: sleep is one of the most important things we can do to manage symptoms day to day and ensure that we're recovering from the day before. People with complex chronic illness rarely get refreshing sleep and often don't get enough of the restorative sleep phases that are so important to recovery. There are many, many things we can do to improve and optimize sleep that rely on different behavioral changes through your day-to-day life — including just monitoring your sleep, which can be a really helpful guide to help you understand how much sleep you're getting, how much of it is good-quality restorative sleep, and what progress you're making with behavioral changes.

In the following videos in this series, we're going to talk about various aspects of your lifestyle, how they affect your nervous system and your overall health, and then different tips and tricks that you can use to manage them.