Found a way to detect Afib during or after the fact

[flroots]

I stumbled across a way to detect Afib during or after the fact. While looking at activity on phone, I noticed Tennis, Brisk Walk, Moderate activity and Intense activity. While Tennis and Walk were programmed by me, moderate and intense activities were detected by the watch itself. I found that the periods of Intense activity corresponded exactly to a recent period of Afib lasting almost 3.5 hours. Out of curiosity I looked back in time and found other periods of Intense activity. These almost certainly corresponded to Afib since the number of zone minutes reported were virtually impossible to have corresponded to any normal activity. I wonder if others experiencing Afib have used this feature to record Afib episodes. I also wonder if there's a potential algorithm that can generate an alarm. For example maybe when intense activity is detected while activity detected by arm motion is low. In other words one should not experience intense activity while relatively sedentary, I really think there is an opportunity for an Afib detection algorithm. Perhaps I should turn this into a suggestion?

[LZeeW]

@flroots   Fitbit tried to study this with its almost year long Fitbit Heart Study.  I haven't seen any published results.  Heart rate changes using the heart rate sensors can be suggestive of A fib.  But A fib is diagnosed by ECG.  But you could also earn those zone minutes from a fever, dehydration, or other situations.

Just my guess, but I suspect Fitbit moved away from using the heart rate sensor when it got the ECG approval and released the Sense.  I participated in the Heart Study.  It was supposed to run for a year or until Fitbit got the data that it needed.  It ended a few months ago.  If there were useful data, then I think major updates for all devices would be out by now.