A Guide to HRV: The Impact of Movement

In this video we're going to be talking about movement, its effect on the autonomic nervous system and its effect on post-exertional malaise. We're also going to discuss how movement affects heart rate variability, and how it can be used to safely help, rather than harm, people with complex chronic illness.

People with complex chronic illness often experience changes to their physiology which mean that when they exert too much energy, they experience a worsening of their symptoms, or even the emergence of new symptoms. This is sometimes called post-exertional malaise. So ultimately the point of pacing is not necessarily to avoid activity, but to complete activity in a way that avoids the crash afterwards.

I think the topics of movement and post-exertional malaise are incredibly controversial, not just to people with complex chronic illness but to medical providers as well. Over the years, there have been many instances of literature showing us that exercise can be viewed as a cure-all for illness. And there's been a substantial misunderstanding of the science behind post-exertional malaise, and how movement can make people feel so unwell when they live with a complex chronic illness.

As we update our scientific knowledge on the topic, we are in fact seeing more and more scientific evidence to suggest that people with complex chronic illness need to adhere to a strict energy envelope to avoid post-exertional malaise. And this absolutely does differ from the consensus scientific literature in healthy individuals, showing that exercise is almost always beneficial.

Whenever we're working with folks with complex chronic illness, the main message is to get to know your own symptoms, and to better understand how much movement is just enough movement, and how much movement is too much and is going to trigger post-exertional malaise. We do want to make sure that people are remaining as active as their symptoms allow, and that can be a really tricky balance. But we should also name the fact that movement can be beneficial to people, so long as they stay within their energy envelope.

As always, heart rate variability can be a useful metric, because it gives us a general sense of our overall health status. As people notice an increase in their heart rate variability, this in many cases may correlate with an improved ability to tolerate exertion and tolerate movement. And as they experience a reduction in their heart rate variability, these may be points where they're highly vulnerable to too much exertion, which might lead to a crash.

Similarly, the consistency of heart rate variability is very important as well. If you're experiencing multiple changes day to day in your heart rate variability — one day it's high, one day it's low, the next day it's very high again — this might be a sign that your ability to be resilient to more movement and more activity is compromised, and you should rest until your heart rate variability stabilizes.

Although we do like to encourage folks with complex chronic illness to move as able, and engage in movement and activity as able, there is a lower limit to that. If you're someone who is in a crash, or who has a severe complex chronic illness to the extent where just completing basic activities of daily living for self-care and hygiene takes it all out of you, then we do not encourage movement beyond that, because that can lead to a severe crash.

So if you're someone who wants to start out exploring your capability for movement without triggering post-exertional malaise, we really need a bit of a mindset shift. Often, when we think about exercise, we think about building up our fitness and getting stronger and going off and running a marathon. That's not the sort of thing that we encourage in terms of safe movement to explore. What we want to be thinking about is movement that isn't geared toward improving cardiovascular fitness. It's movement that is geared toward just getting the body moving, in a situation where you feel safe and comfortable.

The general guidance that we can give is that the level of activity, the level of exertion that you're doing, should never feel too challenging for you. And when we say too challenging, that can be a function of how you feel yourself in terms of exertion, or what your heart rate or heart rate variability is doing in response to the exertion that you're going through. Some days, what you were able to easily do the day before will not be the same as what you're able to do on this day. And the really important lesson — one that deviates from what we tell healthy individuals with regard to exercise — is that on those days you don't want to be pushing through just because this was what you were able to do the day before. You need to listen to your body, you need to listen to your physiology, and that's how you're going to avoid the crash.

Many people with complex chronic illness will also be prescribed rehabilitation activities by clinical providers, such as breathwork, stretching and gentle movement, that do not have the goal of increasing muscle strength or improving cardiovascular fitness, but of retraining appropriate autonomic nervous system responses. This is sometimes called autonomic rehabilitation, and it's very important to note the difference between rehabilitation and exercise that is designed to improve fitness or muscle strength. They're not the same, and one can be very, very helpful whilst the other can be quite harmful.

So to recap, movement and complex chronic illness is a very complex and nuanced topic, and this is something that we all need to navigate very carefully and individually. Movement can be helpful for maintaining what you already have, preventing deconditioning, and optimizing autonomic nervous system health. Being able to monitor yourself — either using heart rate monitoring or heart rate variability monitoring, or even checking in with yourself subjectively and using exertional monitoring — can provide crucial insights into how to avoid too much activity and triggering post-exertional malaise, and how to stay within a safe zone of activity and movement that is beneficial to you.

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.