Blog: Clark Ellis, "Which heart rate monitor for ME/CFS?"

Andy

Andy

Senior Member (Voting rights)
There’s a very interesting discussion about wearable heart rate monitors on Science for ME. I’m not going to reproduce those discussions here but you might want to check them out. It’s free to become a member and it’s a very good forum.

There’s some research which suggests post exertion malaise (the cardinal symptom of ME) occurs, or worsens, in response to exercise and that it may be lessened or avoided by maintaining a lower heart rate. This may explain, at least in part, why people with ME cannot tolerate exercise. Exercise, including graded exercise therapy (GET) is the most dangerous thing a person with ME/CFS can do. So theoretically, by keeping your heart rate down to around 50-60% of maximum you have less symptoms. Or to put it a better way, you can avoid an increase in symptoms. This may still be difficult, or in fact impossible, for some sufferers as their resting heart rate is already close to that 50-60% range and very minor activity, something simple like standing up may push the person over it, but for some it may be possible.

If you do have a little leeway then you may even be able to safely carry out very light exercise (such as stretching, or light resistance training) without inducing a crash if you can keep your heart rate below 50-60% of maximum. I’m not sure there’s enough scientific evidence for that, so tread carefully, but it might be worth exploring, with the caveat that you cannot exercise your way better from ME/CFS. All you might be able to achieve is a small increase in fitness without a worsening of your ME/CFS. Maybe.

A rough calculation of maximum heart rate is 220 minus your age. Multiply that result by 0.60 (60% of your maximum heart rate) and try to stick below that, or 0.50 (50% of your maximum heart rate) may be better but harder to achieve. Each individual is different and it’ll probably require some trial and error.

I have been meaning to get a heart rate monitor for a while but was overwhelmed when I first began looking. There are lots of devices on the market nowadays. The market is largely fitness orientated but it is still finding its feet and some devices are more niche than others. I think the market still has some maturing to do, bugs to iron out both in terms of hardware and software and that means you need to exercise caution when buying a device because chances are a lot of them will have major design and manufacturing faults, particularly in the lower price brackets.
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https://autodidactauthor.wordpress.com/2017/12/18/which-heart-rate-monitor-for-me-cfs/

Bonus points obviously for saying nice things about S4ME @Clark Ellis ;)
 
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It's easy to say nice things about S4ME. :) It was the S4ME discussion on heart rate monitoring that really got me started with some very useful insight from members, so thank you all for that. I've been monitoring my heart rate and sleep a couple of days already and I've found it super interesting. Heart rate right now 68 beats per minute which is fine, but I've noticed some other things that are potentially not so good so I guess I'll be looking into those.
 
Just taken my fitbit HR off my wrist to check. The bit that does the heart rate monitoring is a couple of tiny very rapidly flashing green lights. They are housed in what feels like a metal box which does contact the skin, but it's the reflection from the light that is read as the signal, not contact with the metal, I think. I guess it would be possible to put a thin layer of clear plastic over the metal, but it might effect the reading. I think you'd have to check with the manufacturers.
 
Liv aka Mrs Sowester said:
Daft question, but do all heart rate monitors have the metal contacts?
Metal gives me hives :(
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Not daft at all, I get contact reaction to nickel, and maybe some other stuff. If a device caused me a reaction I'd send it back. It's one of the reasons why I'm wary of straps that people say cause them skin rashes. Most of these PPG devices use green LEDs and light sensors to measure the reflected light that comes back, so glass or plastic as the light has to travel though. Not usually any metal there, though some might have some metal around this? Mine appears to be plastic. But these devices need to be charged somehow and most have the connection points on the back of the device, which in some cases may touch the skin, I guess it depends on the individual device. These are likely to be copper probably with some kind of chemical coatings on. The backs of some devices may be metal in some cases, like standard watches, but most are probably plastic I would guess. The only metal on the back of my one which might contact the skin are the screws that attach the strap to the device.
 
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@Clark Ellis

Each day the Fitbit app tells me what my resting HR is... as the day progresses the number sometimes changes a little.

I have only been using the Charge since July. Often my resting HR creeps up over a few days - that can be during a period when I'm feeling more "well", and it therefore gives me something of a warning that I'm getting too confident of my abilities. Once I stumble physically, my resting HR often remains high for a while, and during that time I'm also not great. Once my resting HR returns to my mid-range value, I feel "better".

Interestingly if my resting HR goes below my mid-range, I can also feel a bit rubbish (like low blood pressure - so I'm guessing sometimes those can be linked??)

Anyway as a general marker of "how I am" it can be useful I think. I can now have periods of several days feeling quite okay, and there is a natural tendency to allow activity to creep up over a period like this. The highered resting HR is a good reminder for me, that my body is not giving me all the information. LOL

Edit to add. It seems Resting HR goes up or down by only a couple of digits each day. Yet the range of values is about 12. Interesting that changes seem to be cumulative in one or other direction.
 
Great writeup @Clark Ellis, thank you!

I may have said it already in the thread you mentioned, but I had to stop using my Mio Fuse bc over time the green lights caused increasing pain in my arm tissues. Not a contact allergy like from nickel but lasting pain in the arm even after I take it off. Such a bummer bc it's so useful to know when we're risking PEM.

Just dropping that here as something to consider/look out for when using these devices. Hopefully I'm just an unfortunate outlier(--ooh good band name!)
 
Keela Too said:
@Clark Ellis

Each day the Fitbit app tells me what my resting HR is... as the day progresses the number sometimes changes a little.

I have only been using the Charge since July. Often my resting HR creeps up over a few days - that can be during a period when I'm feeling more "well", and it therefore gives me something of a warning that I'm getting too confident of my abilities. Once I stumble physically, my resting HR often remains high for a while, and during that time I'm also not great. Once my resting HR returns to my mid-range value, I feel "better".

Interestingly if my resting HR goes below my mid-range, I can also feel a bit rubbish (like low blood pressure - so I'm guessing sometimes those can be linked??)

Anyway as a general marker of "how I am" it can be useful I think. I can now have periods of several days feeling quite okay, and there is a natural tendency to allow activity to creep up over a period like this. The highered resting HR is a good reminder for me, that my body is not giving me all the information. LOL

Edit to add. It seems Resting HR goes up or down by only a couple of digits each day. Yet the range of values is about 12. Interesting that changes seem to be cumulative in one or other direction.
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I'm still trying to figure out how my mine works but I think it may do something similar. It's really interesting that you've noticed some correlation with your resting HR, and the direction of change.
 
Allele said:
Great writeup @Clark Ellis, thank you!

I may have said it already in the thread you mentioned, but I had to stop using my Mio Fuse bc over time the green lights caused increasing pain in my arm tissues. Not a contact allergy like from nickel but lasting pain in the arm even after I take it off. Such a bummer bc it's so useful to know when we're risking PEM.

Just dropping that here as something to consider/look out for when using these devices. Hopefully I'm just an unfortunate outlier(--ooh good band name!)
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Thanks for sharing Allele, that's really interesting - and worrying! I wonder how it's causing that. Do you think it could have had anything to do with pressure from the raised surface or do you think it's the light itself?
 
Clark Ellis said:
Thanks for sharing Allele, that's really interesting - and worrying! I wonder how it's causing that. Do you think it could have had anything to do with pressure from the raised surface or do you think it's the light itself?
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It's from the light I believe, as the sensation is different than from pressure.
It started out not bothering me at all, then over time it would feel worse for longer, until I could no longer wear it.
I tried moving it up or down my wrist a bit but that didn't help.
Am just realising that this happened when I was in a bad phase and had become scarily thin. I wonder if having a bit of arm-fat now it would be better.
 
The little lights work almost anywhere on the body. I have worn mine inside a sock, or my bra. I just took the strap off. Sure I couldn't read the monitor for those days (in smart clothes so didn't want the wrist watch bit), but if I was really curious I could check on my phone app. Having said that I can't read the monitor without my glasses anyway so I rarely read it. @Allele - Maybe wearing the monitor on a different part of your body might help??
 
Allele said:
It's from the light I believe, as the sensation is different than from pressure.
It started out not bothering me at all, then over time it would feel worse for longer, until I could no longer wear it.
I tried moving it up or down my wrist a bit but that didn't help.
Am just realising that this happened when I was in a bad phase and had become scarily thin. I wonder if having a bit of arm-fat now it would be better.
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Light allergy does get a brief mention on Fitbit's site. It says it's very rare for a reaction to visible light which is what it uses, but it sounds like that's what you have. I guess our skin isn't designed to have light like that right up against our skin.
 
Daisymay said:
Great article Clark, thanks!

Do these heart monitors use wi-fi or any form of EMR to function? I ask as I have problems with wi-fi.
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Thanks Daisymay.
I think all the devices I looked at used Bluetooth and I think that's pretty typical of most devices nowadays. Some also use WiFi, and/or 3/4G. You can probably find a device or two still that only connect to a computer via a USB cable or something like that. Some (perhaps most?) devices probably allow you to turn Bluetooth off and only have it on for brief minute or two to transfer whatever data you want.
 
Clark Ellis said:
Thanks Daisymay.
I think all the devices I looked at used Bluetooth and I think that's pretty typical of most devices nowadays. Some also use WiFi, and/or 3/4G. You can probably find a device or two still that only connect to a computer via a USB cable or something like that. Some (perhaps most?) devices probably allow you to turn Bluetooth off and only have it on for brief minute or two to transfer whatever data you want.
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Thanks, that sounds feasible if I could turn the bluetooth off and only put it on to download info.
 
Allele said:
Great writeup @Clark Ellis, thank you!

I may have said it already in the thread you mentioned, but I had to stop using my Mio Fuse bc over time the green lights caused increasing pain in my arm tissues. Not a contact allergy like from nickel but lasting pain in the arm even after I take it off. Such a bummer bc it's so useful to know when we're risking PEM.

(--ooh good band name!)
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Yes, I had that problem with both the Charge and the Mio. I would have loved to wear the monitor regularly but it felt like I was getting arthritis in the arm that had it on. The pain increased over time. I read of many accounts on the internet about people having that same sensitivity. Somebody hypothesized that it could be a sensitivity to EMF. I don't have the same pain when I wear the chest strap.

I just chalked it up to one more quirky thing with this illness.

Lynn
 
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