Cycling Fitness / Training Advice

How are people measuring HRV? I tried it for a while using my Garmin 935 where the protocol was to stand still wearing the HR strap for about a minute just after getting up. I tried it for a couple of months and got basically no signal in the data... I can’t remember the actual values but I never got out of the “most rested” category even after a heavy week or the morning after a HIM tri. So I gave up.

However I’ve been considering a whoop and I thought one of the advantages is that it measures HRV 24/7 rather than a single daily measure. My garmin does also record HRV continuously using the optical sensor however I always thought the optical sensor (in my watch at least) was a blunt tool for measuring HRV and that the whoop uses a higher frequency optical sensor specially designed for HRV. Using the continuous garmin HRV, anecdotally I do see some correlation with my perceived stress... for example I can easily see a spike in stress during the point where I had an argument with my fiancé a few days ago. One of the key features of whoop is that it is supposed to give a score that would tell you when to train and when to rest, but looking back over the past few weeks of garmin data I don’t get anything like that... as with the once daily measure, my overall stress score barely ever even get into the low stress category. Maybe I’m just super chill, or having a desk job provides ample opportunity to rest but overall I get so little information from HRV that I don’t find it useful at all. But I was wondering about trying whoop to see if I get better results with a dedicated device.