https://www.youtube.com/@TheQuantifiedScientist https://www.youtube.com/@TheQuantifiedScientist That guy is a great reference, and through his videos you can f

https://www.youtube.com/@TheQuantifiedScientist https://www.youtube.com/@TheQuantifiedScientist That guy is a great reference, and through his videos you can find various measures where he compares devices against reference devices (e.g. the Polar H10 for heart rate for instance). A lot of the reliability of these devices relies upon a tight fit as well.