A while back, I wrote an article about how your nutrition tracking app sucks. It’s been almost 2 years since then, and it hasn’t gotten much better.
Sometimes, we assume that if it’s high-tech, it’s better. Often, that’s the case, but not always. Another area where high-tech is actually worse than its lower-tech counterparts is wearable devices, like Fitbits, Apple watches, Oura rings, Whoop straps, etc.
Original source: here.
Let me tell you a little story about a 14-year-old watch that I had.
It was a Polar heart rate monitor that I bought in 2008. It cost $110. That watch was fantastic. It had a few major functions:
- The obvious: tell time.
- Measure my pulse.
- Alarm clock.
That’s it. In the 14 years that I had it, I only changed the battery twice. It used a chest strap, so it had near-100% accuracy.
Fast forward to 2022, and after 14 great years of service, that watch was kaput. I haven’t needed to buy a heart rate monitor in that time, so I lost touch with what’s on the market. But now that I needed a new one, I had to familiarize myself with what’s out there. So I did. And almost unanimously, heart rate monitors have actually gotten worse with time. How?
Yes, they now have fancy features, like:
- GPS
- Weather
- News
- Text messages
Awesome! But remember, the single feature that you need out of a heart rate monitor: your pulse. In that regard, it’s gotten worse. Modern-day heart rate monitors have done away with a chest strap, and are just using the wrist to tell you your pulse.
Just because it’s fancier and newer doesn’t mean it’s better.
Case in point, one study compared 3 wrist-worn heart rate monitors to the gold standard (the Polar H10 chest strap):
- Apple Watch
- Fitbit
- Polar Vantage
At lower intensities they were decent. Not amazing, but decent. At higher intensities, they weren’t good. The Apple Watch was the most accurate of the 3. In this case, most accurate meant that it was about 5% off the gold standard. Doesn’t seem like a big deal, does it? At lower intensities, it isn’t. But at higher intensities (especially interval training), it’s close to useless. If someone’s maximal heart rate is 150 beats per minute (that’s what it would be for a 70-year-old), a 5% variation means 7 beats per minute. That’s a lot!
And the Apple Watch was the most accurate. The Fitbit and Polar Vantage were even worse than that. You’re better off measuring your pulse manually (taking 2 fingers to your neck, and counting the beats – really!).
That’s just pulse. When it comes to how many calories you burned, all 3 were atrocious in their accuracy.
- The Apple Watch was off by 14.68-24.85%.
- The Fitbit was off by 13.44-29.66%
- The Polar Vantage was off by 16.54-25.78%.
Terrible.
“But Igor, I use it to track my sleep”, I can hear you say. I get it. It’s tech, it’s got nice, colourful graphs, which makes it look pretty scientific. What’s not to love? Well… the accuracy.
There’s not a single device out there that is an accurate sleep tracker.
The gold standard is called “polysomnography” (or PSG for short). If you were to go to a sleep lab, they’d attach electrodes to your head to measure brain wave activity. I always wondered how watches that don’t attach anything to your head can measure your sleep, the different stages of sleep, etc. Then I dug into the research. They mainly use pulse. And as we learned earlier, they’re not that great at measuring pulse. But even if they were, pulse does not have a perfect relationship with sleep stages.
Original source: here.
Case in point:
- One study showed that the Oura ring was able to distinguish between awake and asleep with 95% accuracy. But um… you don’t need tech to do that. You can do it yourself! However, when it came time to estimating which stage of sleep you’re in (light sleep, deep sleep, REM sleep), it was pretty bad. It had an accuracy of 77-79%).
- The Fitbit and Apple Watch were worse, with an accuracy of 55-78%.
- The Whoop strap could classify sleep stages with about 60% accuracy. Not good.
So the main lessons here are:
- I’m getting to be crotchety, with stories of “back in my day…”
- Just because it’s fancy and high tech doesn’t mean it’s accurate.
- Modern heart rate monitors are just pretty expensive pedometers.
- Yes, they have some cool features, but you can get those features on your phone or computer (like GPS, weather, text messages, etc.). The one thing that you really want out of them (accurate pulse tracking), they don’t do well.
- I miss my 2008 Polar Heart Rate monitor ☹
So what should you do if you want accurate heart rate tracking? You have a couple of options:
- The super low-tech option: measure using 2 fingers on your neck. It’s actually more accurate than modern-day heart rate monitors.
- If you want the gold standard (near-100% accuracy), get the Polar H10 strap, and connect it to your phone.
If you want accurate sleep tracking, go to a sleep lab. I understand that you can’t go to a sleep lab every night, but you can wear the watch every night. However, is that watch/device worth it if the data it’s giving you is inaccurate data? No data is quite a bit better than bad data. Lots of research has found that people who obsessively track their sleep with these devices paradoxically have worse sleep.
So say good night to the near-useless wearable devices. Get a watch that tells time, and nothing else. Get a heart rate monitor that tells you your pulse and nothing else. Everything else, you can do on your phone or computer.