30 June 2026

Goodhart goes to bed!

This BBC article caught my eye. It resonated strongly with my own experience. I would be curious to hear from others who use sleep monitors – has your experience been similar?

I used to monitor my sleep religiously. Every night, I wore my Apple Watch to bed. Every morning, I would wake up and check not just how long I had slept, but also the quality of that sleep. I did this for years.

Fun fact: if you sleep for a really long time—something like twelve hours—you can actually earn a “blue ring” on the Apple Watch. Ask me how I know…

It got to the point where I would wake up, squint at my watch before I had even put my glasses on, and immediately decide whether I felt energetic or tired based on whatever number it showed me.

Then one day, I began to suspect that Goodhart’s Law might be at work: when a measure becomes a target, it ceases to be a good measure.

So, about a year ago, I decided to run a little experiment.

(I can be incredibly nerdy when the mood strikes.)

I kept a pen and paper on my bedside table. Every morning, before looking at my watch, I forced myself to ask one simple question: Do I actually feel well rested? I wrote down my answer.

After a month, I downloaded all the sleep data and compared it with my notes.

There was absolutely no pattern.

In fact, on several days, the two completely contradicted each other.

I kept the experiment going for another two months, just to make sure.

The one conclusion I came away with was this: my feeling of being well rested (or exhausted) was being governed almost entirely by what the sleep monitor told me—not the other way around.

That was the day I stopped wearing sleep monitors altogether.

I also retired my running watches.

For the last nine months or so, I have been trying to do something much less scientific and much more difficult: listen to my own body.

I’m still learning. But I don’t miss the gadgets at all.

Instead, I now have a wrist bracelet made from bike chain. I tell myself I look way cooler now 🙂



Posted June 30, 2026 by Rajib Roy in category "Musings

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