Update 1: Using a heart rate monitor to better manage MECFS (including HRV)

In mid June, I talked about using a heart rate monitor to better manage MECFS. I thought it might be useful to post an update and let you know how it’s going. And I’m adding information about another useful measurement, Heart Rate Variability (HRV).

Heart Rate Monitor (HRM)

Using the Heart Rate Monitor (HRM) has been incredibly helpful. Firstly, it’s keeps me aware of when I am reaching my anaerobic threshold (AT). As I mentioned in the first post, it doesn’t take much to reach my AT, i.e. just brushing my teeth does. I have started noticing how long it takes before I reach my AT, sometimes much more quickly than others, depending on the nature of the activity and on how I am feeling that day. It’s a good indicator of how the symptoms of ME fluctuate even over the space of an hour, let alone a day or longer. On a ‘good day’ I can sit up and speak to someone for a little while and my heart rate might be 84. Yet if I sit up & chat for too long, my heart rate can go into the 90’s and I can even reach my AT. I am constantly checking the HRM when talking, not because I’m bored, but because it’s an indicator of when I should stop and go and rest. As the idea is to NOT reach my AT.

So using the HRM is bringing about the behaviour change that I need if I want to improve a bit. It’s really hard – I mean, stopping part way through a chat with a friend isn’t easy. But it’s what I have to do if I want to see some relief in my ME symptoms. Using the alert helps me make ongoing decisions about what I can and cannot do on any given day or hour, and is slowly making me change what activities I plan. If it’s a shower day, then I cannot prepare food and cook, so I plan food prep/cooking around the non-shower days. This is a key part of pacing, but the difference is that the HRM is helping me make this actually happen.

Crucially, the ‘alert’ (a vibration on my wrist) is key to me recognising how unwell I really am and how much I need to change. This feature is really essential, as it really does make me stop and rest. Without this feature I would continue to push myself, as I’m terrible at stopping, particularly mid-task.

Heart rate variability (HRV)

One thing I didn’t talk about in the original post, was heart rate variability – HRV. At the time, I was more focused upon trying to keep my heart rate down during the day as I undertook different activities. But another factor that the articles I read, such as Hannah’s Story stressed, was the importance of measuring HRV. This tells you “whether your nervous system is in balance, or whether you’re swinging into either parasympathetic or sympathetic dominance, i.e. whether we’re crashing, so our very own PEM (post-exertional malaise) detector”.

HRV measures the variation of time in milliseconds, between one heart beat and the next. The average HRV¹ for a person of my age (53) is c. 57. When I first started using the FitBit, my score was 19 and my average for the 1st month was 22. This is yet another measurement that helps show just how unwell people with ME are.

Using the HRM gives me an in the moment idea of how I am doing and helps to know when to stop and rest, and the aim is to try and not go over my anaerobic threshold of 100bpm (as discussed in the first blogpost). HRV gives an overview of how I am doing over a longer period of time, and the aim is to pace in such a way that I increase my HRV over time. Interestingly, my average since starting to measure HRV has gone from 22 to 24 milliseconds. A small but important improvement.

I should mention, that I have been keeping a record of all my stats, in a spreadsheet which I update each morning (particularly as a number of stats, such as HRV, are captured by the Fitbit when I’m sleeping). This is how I can start to see trends, such has HRV going up or down, which in turn help me get closer to working out my baseline and what activities I can plan in the coming days/week. At the moment I’m also recording the daily number of steps, my resting heart rate, and how much sleep I’m getting, etc. With steps, the aim, the opposite to most people using a Fitbit, is to stay under my current ‘goal’ of 2,200 per day. My average is 3,006 – oops! Filling in the spreadsheet has become a part of my daily routine. It only takes a minute or so, and the information I am gleaning from this is definitely worth it.

Overall, I’d say that using the HRM and monitoring HRV, has started to bring about tiny improvements. And when you have a chronic illness like ME, tiny improvements matter. I am beginning to plan activities that better fits where my MECFS symptoms are, which at the moment is still doing very little. And again, it gives me the confidence to show that a) I really am ill, and b) that there is finally something I can do that can help me pace better and relieve some symptoms and impacts of MECFS on my life. There is a dim light in the long tunnel.

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Note: I would love to see companies who produce heart rate monitors and similar devices, start developing tools to help people who have chronic illnesses and ill health in general. All these devices currently focus on fitness: have your reached your goal today?! I think it’s time they started focusing on wellness: be careful you might be doing too much today, take a break. Interestingly, there is some work being done on this by researchers for Long Covid (which has lots of cross-over with ME) in Scotland. The University of West Scotland is running a Fitbit trial which asks patients to stay less active! They are developing an app that will send messages before you get to the point of exhaustion. I so wish I lived in Scotland now.

1. I found a couple of different charts on the web with this info, broken down into the women/men genders, the Normative HRV Scores by Age and Gender [Heart Rate Variability Chart] and Normal Heart Rate Variability: Average HRV Range by Age and Gender. For simplicity’s sake I went with the female chart in the 1st one.

See also: Using a heart rate monitor to better manage MECFS.