Devices for Pacing by Heart Rate *Variability* (not by heart rate)

[TJ_Fitz]

I haven't had much success with pacing by heart rate. I've found that it just doesn't accurately reflect the stress level of my body. For example, reaching up over my head to deal with some items on a shelf immediately spikes my heart rate but doesn't cause PEM, but sitting still and reading, watching TV, or playing games on my phone for too long can indeed zap me. Add to that, as a CIRS patient, I get flares from breathing in bad air, which has nothing to do with exertion. So pacing by HR just isn't useful.

What might be useful, however, is something that can warn me of changes in stress level (via changes in HRV) and that can tell me how recovered I am so that I can plan around recovery level regardless of how I feel. This is important because I also have bipolar 2 disorder, and I feel quite good on those hypomanic days regardless of how well I've rested and recovered.

My Garmin is supposed to do both of these things, but it doesn't do them very well. Can any of you recommend wearable devices that are good at tracking your state of rest/recovery AND good at warning you of acute stress events?

 

[Frangipani]

Oura ring? Cort Johnson from Health Rising mentioned using one to track stress.

 

[TJ_Fitz]

I looked at those, but ultimately decided to upgrade from the old Garmin vivosmart 4 fitness band to a vivoactive 5 smartwatch. I really like the "body battery" feature, and the vivoactive has improved stress and sleep tracking, and also attempts to monitor recovery state. So far I haven't been able to get stress alerts working, but at least I can see stress levels on the watch face.

 

[TJ_Fitz]

I haven't had any success thus far discovering a way to pace by HRV without either wearing a chest strap or buying one of those Polar Verity Sense armband sensors (it's optical but still accurate for HRV readings -- and expensive). However, I have found that pacing by heart rate actually does work for me, if I'm using the right threshold.

Background: the day before beginning my Workwell study, I had a very long walk through my departure airport, a flight breathing recycled air (that's a problem for people with CIRS because of cross-contamination and human-produced VOCs), and another long walk through my arrival airport. Then I spent the night in a motel room with a water-stained ceiling (again, big problem with CIRS). So I went into day 1, in which my aerobic threshold was measured at 94, already impaired from overexertion and exposure to bad air. After the day 1 study was done, my wife and I did some sight-seeing in the San Francisco area (again, too much walking), then spent another night in the water-damaged motel room, resulting in an aerobic threshold of 89 on day 2.

Based on my day 2 results, Workwell recommended that I pace myself at a heart rate no more than 89, but I could barely do anything at that rate, and more importantly, I felt worse and worse, and wasn't sleeping well because I was too wired. I realized a few weeks in that I needed to exert myself more than I was, so I started moving up my threshold. Yesterday I went out for a walk and decided to pace myself based on the "breath test", or how I felt, while watching my HR. Based on that, I estimated my threshold to be around 105 at the time. Naturally it's going to fluctuate, depending on overexertion/PEM and exposure to indoor air pollution.

 

[Kpont]

I find the Visible app works reliably - you just need to be disciplined about taking the reading first thing each morning. Note - if you have POTS, it’s better to be lying down. If not, sitting up is better.

I’ve found that other apps, including my Apple Watch health app, don’t do as well because they aren’t made for CFS. They are made for Exercise, tracking, and recovery (so the algorithm isn’t quite right).

 

[TJ_Fitz]

No POTS here, thankfully. That sounds like a good way to get a "morning readiness" score. There are several others that do something similar as well (like Elite HRV). My Garmin watch actually does this, too, with their "Body Battery", and it updates throughout the day.

I don't think anyone makes what I'm looking for! I want a near-realtime HRV measurement with alerts when the measure drops too low. It would need to be a rolling measurement. For example: display the lnRMSSD calculated over the past 20 seconds, and update/recalculate every 3 seconds. After becoming familiar with typical scores at the edge of my tolerance, I could set a threshold and get a warning whenever the number fell below it.

I'd use lnRMSSD (natural logarithm of root mean square of successive differences) because the RMSSD seems to be a good short-term measure of how relaxed you are. Taking the natural log makes it more linear. I'd probably multiply it by 10 or 20 to make changes more obvious, too.

If I can ever get my head in the right place, I might even attempt to create a app for my watch or Android that does such a thing, but it's probably just another item on a long list of good ideas that I'll never get around to doing.