Nov 27, 2023·edited Nov 27, 2023Liked by Marco Altini

Hello Marco, I appreciate you for providing all this information. Without it we might have great tools but would not be using their potential.

Since Oura and whoop are too expensive for me, I'm thinking about buying one of the devices you usually wouldn't recommend. I'm wondering why you don't recommend certain device, for example fitbits and Google pixels. Your criticism concerns

(1) sporadic sampling, or

(2) shorter time windows, or

(3) unclear processing".

However, as far as I understood (see source below)

(1&2) fitbits uses data from an entire night of sleep

(3) fitbit uses rMSSD to calculate hrv

Quote: "Fitbit uses the common formula called RMSSD to determine HRV from your recent heart-rate data. In the graph, your latest HRV measurement is from the longest sleep period over the past 24 hours. Only sleep periods greater than 3 hours are considered."


What exactly do you not like about hrv readings from fitbit devices then?

Thank you.


Expand full comment
May 31, 2023Liked by Marco Altini

Hi Marco & team, How do I connect garmin HRM pro to the app for HRV?



Expand full comment
May 17, 2023Liked by Marco Altini

Thanks, Marco! We have the Scosche Rhythm24 and Kyto2935 in our validation pipeline, and surprisingly, they don't seem to be promising, even during sitting still conditions. My observation is that there is considerable variation between individuals; I have participants for whom these sensors do not even transfer the data (potentially confounding factors such as BMI, skin color, or even blood pressure may play a role). When a sensor fails to provide a good signal - or even any signal at all in some cases - in a participant, out of curiosity, I sometimes test it immediately on my hand/earlobe, and it works just fine. Hopefully, the first draft of the paper will be ready in a few months and love to hear your thoughts on it :)

Expand full comment

Hey Marco could you recommend some non contact HR sensors that you like?

Expand full comment

Hello Marco, got it thanks.

Best regards, Dennis

Expand full comment