Est. 2023 · Denver, CO ktb/os · live
Field Notes · 7 min / field notes · 7 min

I bought a smart ring for the vibes. It ruined my sleep.

A week with the Oura Ring 4 taught me more about placebo effects than it did about my own body.

The Oura Ring 4 arrived on a Tuesday. On Wednesday, I had my first bad night’s sleep in months.

This is, statistically, a coincidence. Bad nights of sleep happen. I had a late coffee. The windows were open and I heard a fox at 2 a.m. The ring, in fact, did not cause the bad night.

But on Thursday morning, I reached for my phone and opened the Oura app before I’d stood up, which I had promised myself I would not do, and there it was: a score of 64, and a little chart telling me my “readiness” was low. And from that moment, I was — against my will, against my better judgment — a little worse.

I’ve worn the ring for a month now. I have come to believe that wearable health tech, at least for me, at least right now, is a trap. Not because the devices are bad. They’re good. They’re, frankly, miraculous. But because I am bad at being told a number about myself before I’ve decided how I feel.

Here’s what I learned.

The ring is a beautiful object

Titanium. Matte. Weighs nothing. Fits under a watch. Doesn’t set off metal detectors, though it makes the TSA agent squint.

Charging is a tiny plastic puck you plug into USB-C. The battery lasts a week. Updates happen overnight. The app is tasteful, the charts are legible, the data export is a CSV file, as God intended.

If you’re buying a smart ring because you want to own a piece of small, beautiful, well-made hardware, you’ll be very happy. The Oura is a nicer-feeling thing than most watches I own.

The data is pretty good

I’m not a scientist. I can’t tell you whether the heart-rate variability it measures at 4 a.m. is clinically accurate. But I can tell you that when I stayed up late, it knew. When I drank, it knew. When I went for a run, it knew, and when I skipped one, it knew that too.

For the first week, this was thrilling. I was — I thought — getting a window into myself. My body was a system. The ring was an oscilloscope.

For the second week, I started to notice something uncomfortable.

I was optimizing for the ring

Not for sleep. For the ring.

I started going to bed twenty minutes earlier because I knew the ring would reward me. I stopped eating dinner after 8 because it docked me for late meals. I stopped drinking the occasional glass of wine because the readiness score was brutal about it.

These are, mostly, good choices. Eat earlier. Sleep earlier. Drink less.

But I was making them for the wrong reason. I was not making them because I felt better. I was making them to move a number. And because the number was opaque — “readiness” is a composite of sleep, HRV, temperature, activity, and ineffable Oura Magic — I couldn’t tell which of my new behaviors was helping, or whether any of them were. I was doing rain dances for a god whose preferences I couldn’t decode.

The mornings got worse

The worst thing the ring did was take over my mornings.

Before the ring, my morning routine was: wake up, feel a way, decide if the way was good, get out of bed accordingly. Sometimes I’d feel tired and go back to sleep. Sometimes I’d feel great and go for a run. My body and I had a working relationship. We disagreed sometimes, but we were in conversation.

After the ring, my morning routine became: wake up, check the ring, discover whether the way I was about to feel was allowed. A 90 readiness and I’d go for a run, regardless of how I actually felt. A 55 and I’d mope, regardless of how I actually felt.

A hundred thousand years of listening to my own body, and a twelve-hundred-dollar piece of titanium had replaced it with a number.

The placebo works in both directions

Here is the most unnerving thing. On the days when the ring said I’d slept badly, I’d be tired — whether I had or not. On the days it said I’d slept well, I’d be energetic — whether I had or not.

I tested this, casually. A few times, I looked at yesterday’s score instead of today’s, by accident. When I saw a low score, I felt worse than I had thirty seconds earlier. When I saw a high one, the tiredness I’d felt a minute ago got reinterpreted as the kind of good tired you get from a useful workout.

The ring was, in some non-trivial sense, manufacturing the feelings it claimed to measure. Or at least shaping them, at the margin, in a direction I hadn’t asked for.

Who the ring is for

I think there are two kinds of people who should own a smart ring, and I am neither of them.

The first is someone with a specific, tractable health problem — a sleep disorder, a metabolic condition, a training plan that genuinely needs HRV data — who treats the ring as an instrument. They look at the data when it’s useful and ignore it when it isn’t.

The second is someone so psychologically sturdy that a 64 is just a number on a screen. These people exist. I know two of them. They wear the ring to bed and treat the morning score with the same affect they give the weather.

I am, it turns out, neither of those people. I am a person who will happily let a little titanium loop tell me, against all my accumulated evidence, whether I had a good night.

The verdict

I took the ring off last Monday. I haven’t put it back on.

The data is in a folder on my computer. I’ll look at it, occasionally, when I want to know something specific — did I actually sleep badly that week, or does it just feel like I did? Those checks are useful. They’re the way instruments should work: you reach for them when you need them.

What I won’t do anymore is strap an instrument to myself all the time and let it tell me how I’m doing.

I can just ask.


Matt has the opposite take on the Oura — he wore his for a year and loved it. We recorded an argument about it for the channel. Spoiler: we didn’t resolve anything.

“The worst thing a sensor can do is be wrong. The second worst thing is be right, at 3 a.m., about something you can't do anything about.”
WRITTEN BY
Michael Kelso

The older one. Writes essays about the shape of software and runs the Linux rig nobody asked him to build.