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

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

 

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.

 

Daft question, but do all heart rate monitors have the metal contacts?
Metal gives me hives

 

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.

 

A detailed and useful post @Clark Ellis ... Though I have to say I've no complaints about the Fitbit HR Charge2 (I think that is the name of the one I have) or the app that goes with it. I like the "resting HR" feature in particular.

 

Specific metals likely give you hives. Nickel is a common culprit. Or brass (copper/zinc alloy).

That said, my Garmin (hand me down) heart rate monitor does not use metal on the chest strap.

 

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.

 

Thanks Keela Too, and that's good to hear about your Fitbit. What does the resting HR feature do on yours?

 

@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!)

 

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.

 

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?

 

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??

 

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.

 

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.

 

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.

 

Oh, wow, didn't know it was a thing! Lucky me, I guess

 

Thanks, that sounds feasible if I could turn the bluetooth off and only put it on to download info.

 

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