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Comment by anonporridge | Hacker News Reader

Sleep quality would be a better metric than duration.

HRV is generally the metric used. You can measure that with a cheap chest monitor, or get a fitness watch that tracks it continuously throughout the day and night.

Good HRV levels are highly correlated to activity level, so your base hypothesis still makes sense.

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Good point.

Is there a standardized way to measure sleep quality? Or are the numbers one measures only compareable as long as one uses the same device?

I would be interested in suggestions which watches measure the HRV / Sleep quality reliably and display the data on screen. Or let me get it from a Linux laptop. I hate having to install an app to get the info off the watch.

HRV is indeed a good proxy metric for sleep quality, and I can really recommend Garmin watches for measuring it. Even the cheap models track the "Stress" metric 24/7 (which is HRV under the hood). More expensive ones have pulse ox monitoring and a full blown sleep analyzer that provides sleep stage breakfown and a compound sleep quality score. All from just being worn on the wrist normally through the night.

However, HRV is not the whole story about sleep quality. If you develop sleep apnea, for example, your HRV will not react very much, though your sleep quality will suffer. There is no substitute for sleep study to detect such issues.

HRV is indeed a good proxy metric for sleep quality, and I can really recommend Garmin watches for measuring it

I'm a little skeptical about my Garmin's ability to accurately measure sleep quality.

Sometimes I wake up refreshed and felt like I slept very well, only to have my Garmin tell me that I had poor sleep quality (usually because of too little REM sleep), other times I've had a bad night of sleeping (like the dog needed to go out several times) and I wake up tired, and my watch congratulates me on good sleep quality.

I wonder if one of the sleep monitors that uses a pad on the mattress would be more accurate.

Sleep apnea isn't really detected by HRV no bit pulse ox is a pretty good indicator.

My understanding is that different devices measure HRV with different techniques, so they're not necessarily comparable. I've heard Apple Watch is especially bad at measuring HRV, while Garmin and Whoop are good.

One performance and health coach I follow recommends the Polar H10 chest strap to take a measurement every morning.

https://twitter.com/Alan_Couzens/status/1723334537235607989

https://twitter.com/Alan_Couzens/status/1473672665541984259

There's also not an absolute number or threshold that's good or bad. Generally higher is better, but what really matters are the fluctuations from a personalized baseline.

Is "take a measurement every morning" about sleep quality or about something else?

Is it even possible to sleep with the H10 strap?

Taking a measurement at the same time every morning helps to establish a consistent baseline so that you can detect changes from day to day. But the latest generation of smart watches can track HRV continuously throughout the day, so if you have one of those then taking specific measurements is less useful.

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