My experience with the vivosmart4

It's an interesting toy and PEM is visible in the data it collects. It tracks steps per day (imprecisely), heart rate, stress level, body battery, sleep phases. I'm not sure what measurements the stress level and body battery are based on.

The body battery is the measure that seems most useful. When I clearly overdid it and then could not recover properly from the exertion, this was visible in the body battery. First, on the same day of the exertion, it showed a failure for the body battery to increase with rest and this is exactly how it felt to me. I tried to rest several times but could not relax and was not able to recover fully from the activity. The next morning, it showed the body battery had recharged to 67, whereas in the previous 3 days I had woken up with a charge of 100. And this also matches roughly how I felt.

Listening to one's body is more accurate than the device I think, but it's still nice to see I'm not imagining things.

 

I also have a vivosmart4. (Currently not wearing it due to skin reaction with the band and I got a bump on my arm next to it.)

It's a really nice device. It's far from perfect, e.g. it really struggles with tachycardia in combination with orthostatic hypotension.
(So when in the shower it peaks but the measurement is often slower than counting actual pulse by hand, and when I have bad tachycardia under the shower, it can happen that while my manually felt and counted heart rate drops when sitting down for a bit, the heart rate monitor rises because it can better measure heart rate with rising blood pressure.)

But like you it's a nice crude general observation tool. I find the body battery not very useful in daily numbers related to how I feel, but it does show trends accurately: weeks with higher scores are better than those with low ones. And a current antibiotics course is clearly visible: the body battery score dropped like it fell of a cliff. I can also observe PEM and bad crashes in the "stress" monitor. I find it actually measures physical stress a whole lot better than mental stress. Prominent PEM for me on the device can look like a block of high stress throughout the day while I'm actually lying down and reading.

And of course you have a crude step count, which again is not so much use to me daily, but it does show trends.

 

I believe Heart Rate Variation (HRV), you can find it in the app.

(Can't look it up now, my phone is charging and I'm Stuck Under Cat.)

 

The observation agrees with my pacing strategy that aims to arrive at the end of the day feeling like I have some spare energy (instead of being totally exhausted and/or wired and unable to relax).

 

I have the vivoactive 3 and you can add a HRV widget but you have to select it each time you want a reading.

it doesn’t have the body battery function but it does have the body stress one. I have been using it for a few years now and it is really good at showing when your body shouldn’t be doing any activity. Sometimes I might feel not too bad and think I should do something useful ( housework , light gardening) but I check the body stress and it is really high so I take a day or two longer to relax. It then goes right back down.

I have noticed that if I do take the time to relax until my body is ready, when I do then exert myself ( like walking upstairs) it doesn’t take as much of a toll as it normally would. If I am tired my heart rate normally goes racing and the body stress goes up to high 90s. But if I am rested this doesn’t happen.

so I find it really helpful in working out what I can or can’t do when I think I am feeling okish and want to make the most of thinking I am ok to do normal activities.

 

Another interesting observation: during a PEM day, my stress level went down after a good meal. This is something that I've seen many times before I started using the device. The increase in blood sugar seems to help the body handle whatever it's going through.

 

On indicators of recovery from PEM according to the device. Looking at my "body battery" level in the morning after waking up, it took 5 days to reach a level of 97 (out of 100). During the previous days with PEM the level was much lower, suggesting a failure to recover during sleep. The stress level was also very low on awakening.

 

@Simon M very kindly gave me a vivosmart4.
It was quite a while before I finally started using it (I have to pick my time for mastering any kind of new tech), but have been using it for most of last year. Given my recent additional health issues, I have found it very useful. I only really used the immediately available things on the watch itself, ie heart rate, steps, stress level,spO2, VO2,body battery.

Very recently I've started wearing at night and today I began uploading the data so I can view the Garmin reports.
The sleep one was a real eye opener showing me waking up many times throughout the night, and getting less than an hours deep sleep.

I know that RCTs are now more often being conducted using wearables.
I really think it would be worth some research being done just comparing pwME compared to healthy controls reports of this kind over a given period of time, without it testing any kind of regime ,treatment or schedule.
Even if the readings are not that accurate, they will be comparatively useful.

eta:
sleep report for last night

 

I've been using Vivoactive 4 for 3 years and I find it fairly accurate when it comes to times and waking ups during sleep. I have a sensor from other company (forgot name) to put under mattress to record sleep, but that I found absolutely unusable. It records the whole time spent in bed as sleeping time so I've had 23+ hours as "sleeping" in data.

 

I’d forgotten all about that, and I am proved useful. I’ve tried another number of devices and methods, and even the very expensive WHOOP device (which I had on a free trial) wasn’t very accurate on sleep stages. Certainly, it would sometimes tell me I was sound asleep when I was simply lying still and Breathing slowly, but mentally too-alert.

However, if the reported wake times correspond to times you know you were awake, that’s a good sign.

 

I'm getting better acquainted with the online reports so have been looking at the graphs for the last week or so, and they are pretty good in terms of accuracy re sleep. I know when I've had a particularly bad night and now I can see why, or at least it confirms that I've been waking at regular intervals during the night.
From what I've read on reviews about the vivosmart4 it can take a while to get used to your sleep patterns so I'll see how it goes.

What to actually do about the problem of not sleeping properly though is still an issue that needs to be figured out.