Sleep tracking for people with AF and Heart Arrhythmias

[DPinOz]

Arrhythmias seem to affect -
Fitbit sleep stats (Sleep Stages; Deep REM, Sleeping Heart Rate, Blood Oxygen Variation), Heart Rate Variability, Oxygen Saturation, and Breathing Rate.

The result is that Sleep and Health metrics are not tracked. For me this happens most nights (Arrhythmias generally occur more frequently at night in most people due to heart rate and blood pressure drops during sleep and rest).

The Fitbit does a good job of identification of AF, but it seems that these same people who may most benefit from fitness tracking and data are then left out.

Seems odd that Fitbit are missing a big market segment in an aging population. Your own in-house data would probably show market size.

My guess is that most of the missing data is a result of the sensitivity of the measurement due to a too short a measurement time interval. For example and most likely, Heart Rate Variability is being measured over too short an interval (30sec to 1minute) with comparison periods too close. Could the time intervals be relaxed to several minutes? HRV per 5min? This should make this data less sensitive to Arrhythmia variations.

My feeling is many of the glitches reported for sleep tracking are due to Arrhythmias and Bradycardia. Especially in fit adults with low resting Heart Rates below 50 bpm. For most AF causes increased Heart Rate resulting in palpitations, however in fit adults with lower resting pulse rates the AF just causes an irregular beat and a slight wave change on ECG.

If I am correct, Fitbit will get more reports and returned "faulty" watches. A software fix may reverse this, and forge a stronger market segment.

[LZeeW]

@DPinOz   I have some information for you about Fitbit's HRV measurement.  Fitbit only measures this during sleep and only in a sleep period of three hours or longer.  You can see this by tapping on your Health Metrics tile > the Learn More in the HRV section > slide the toggle to about.  It isn't an extremely short time period.

I agree with you that arrhythmias can affect sleep stage measurement and analysis.  I saw this in my husband.  For a while, he was in AF some of the time, but not all of the time.  He was wearing an Ionic at the time.  He got sleep stages when he was in a normal rhythm.  He usually got a sleep graph with no sleep stages, except for light sleep from start to finish when he was in AF.  It is my understanding the HRV changes in different sleep stages and is part of the information that Fitbit uses.  I know that many users who are in AF don't get sleep stages at all, just sleep patterns.

I disagree with you about bradycardia.  My RHR is less than 50 most of the time and has been as low as 43.  I never have a problem getting sleep stages or Health Metrics data.  There used to be a Help article that said that low heart rate limit was 35.  I looked for that information because a user with a RHR of 38 wasn't getting sleep stages.  I think this user is an exception.

I think it will take more than a simple software fix for this.  When I read articles about HRV, images trying to explain HRV always show a normal heart rhythm.  I haven't found anything about HRV and AF or other arrhythmias in simple internet searches.