If we’d played our cards right, my GPS watch and I could have walked from Montreal to Mexico City and back again, such was the distance we’ve covered together in the last seven years. But the poor thing is now beyond battered, so I did what anyone would do and asked for a new one for Christmas. But what I got was a fitness tracker, which, in case you are lucky enough to remain blissfully ignorant, is a GPS-capable watch that allegedly does everything short of brew its own coffee (although, next year’s model, maybe…). In the meantime, unlike my trusty old GPS watch, which did not pretend it could do things that it could not do, what this fitness tracker does turn out to be good at brewing is my rage.

To be fair, this predicament is my own damned fault. I wanted to be able to track my heart rate without wearing electrodes strapped to my chest because it’s uncomfortable and the strap always slips as I bounce along down the road. Fitness trackers do not bother with that shit. They shine a little set of lights at the veins in your wrist and, if you can believe what you read on the internet, measure the extent to which that light gets absorbed. That amount decreases in between heartbeats, when blood is not flowing as much as it does during heartbeats, giving the fitness tracker something to count. But this turns out to be way more brilliant in theory than in practice.

Again, I have no one to blame for this pickle but myself, because I’d also read on the interwebs that wrist pulse heart rate monitors “aren’t accurate” “and can easily be off by 10%” but I’d decided to give it a go anyway. Ho-ho, I thought, I still have my old GPS watch with the chest strap heart rate monitor. I’ll just use both systems simultaneously several times, thereby calibrating the wrist pulse heart rate monitor. Then I’ll know if a reading of 110 beats per minute means that or if it means something more like 121 beats per minute. But, boy, was that naïve of me. Because what “not accurate” turns out to mean is not that there is a continuous, consistent error, but that most of the time the fitness tracker is spot on with its heart rate measurement and the rest of the time it’s spewing total garbage. And by total garbage I mean, in the midst of my exercising, zooming off down to 45 bpm (which would be great if I was fit, but my heart has never beat so slowly at any point in my entire life, not even when it was in the midst of failing a couple of years ago), and then at some point, two, ten, or fifteen minutes later shooting up to ten or 20 bpm over my actual heart rate before wandering back down (if its fit is over, that is) towards a reasonable value. The problem with this, aside from the two, ten, or fifteen minutes that my blood is boiling with rage (which is really, really not good for my heart these days) and I want to smash the fitness tracker with a very heavy hammer (which I at least have the foresight not take out with me on my jaunts), is that everything the fitness tracker calculates about its bearer’s fitness is based on its measurement of its bearer’s heart rate. And that means, if you’re wearing one, the picture the fitness tracker is painting you of your fitness is considerably misleading.

For starters, this means the particular fitness tracker I have isn’t correctly logging my number of minutes exercised each week, you know, that number that is suppose to be at least 150 minutes of moderate exercise or 75 minutes of vigorous exercise or some correctly calculated combination thereof if you want to take care of your heart. Although the recommendation agencies have updated the rule that this exercise has to be done in segments of greater than ten minutes’ duration to count to the rule that every little can be counted toward the total, no one has told my fitness tracker this. It ignores any segment under ten minutes in length. And so some days I really hate it, because between the cutting out that it’s doing and the many pauses because you run into a neighbor or because the dog needs to stop and sniff some other animal’s dried urine that cause my heart rate to briefly drop out of the moderate exercise zone, I can come back from 90 minutes of exercise that probably had 80 minutes at a heart rate high enough to count as moderate exercise, but the fitness tracker logs exactly ZERO. Yes, of course, I still got that exercise, yay, heart! But if a company is selling a fitness tracker as a fitness tracker, it needs to do its tracking way better than this.

And the problems really only spiral out from there. The fitness tracker also likes to track my VO₂ max and tell me what my “fitness age” is. The fitness tracker calculates VO₂ max based on the heart rate it takes for me to walk a mile on the flat at a certain speed. So of course my VO₂ max skyrockets into brilliant values after one of these bad measurement episodes where my heart rate “goes down” to 45 for multiple stretches while I am briskly walking. And while I love the rush of seeing an exercise age fifteen to 20 years younger than my own, this is horrendously misleading, for the truth of the matter is I am now a depressingly unfit middle-aged woman with a flu-damaged heart that freaks out if it goes over 120 beats per minute (moral of this story: ALWAYS GET YOUR FLU SHOT BECAUSE IT FUCKING SUCKS TO BE BROKEN DECADES AHEAD OF SCHEDULE).

Caveat emptor, you might say. But there are real world consequences to the fitness tracker’s lies. Another thing you’ll read on the interwebs when you hate Google fitness tracker heart rate monitor cuts out during exercise is that there are people who have to wear these things to get decent rates on their health insurance. If they don’t hit their weekly exercise targets, premiums go up. And if the fitness tracker isn’t logging all your minutes because its wrist pulse heart rate monitor has a heart attack every time you bend your wrist (because you’re riding a bike, doing yoga, lifting weights, or, you know, just moving normally) thereby diminishing the blood flow through your wrist, causing the measurement to go haywire, then the health insurance company is basing its premiums on a faulty metric. I was also reading about the tests of coronavirus vaccines where they jabbed people and gave them a fitness tracker they had to wear for the duration of the study for data collection purposes. And that just made me want to SCREAM.