Resting Heart Rate vs. Sleeping Heart Rate? Does sleeping use HRV, etc?

[SteverinoLA]

What exactly is the difference b/t resting heart rate and sleeping heart rate as measured by Fitbit device (I have Charge 3)??  I can see my heart rate throughout all 24 hours including sleep, so what exactly is Fitbit measuring to calculate the new sleeping heart rate that requires premium subscription to see?  Does Fitbit measure HRV (heart rate variability) or is it just heart rate plus restlessness???

[SteverinoLA]

What a minute... did Fitbit actrually remove the daily graph of heart rate?  Used to be in app for sure but now I don't see it.  I can see this info on web site dashboard for Heart Rate in 5 min intervals.  Arrrg, is this info now removed from app b/c it's locked behind the premium paywall too?   Oh boy.

[LZeeW]

@SteverinoLA   You heart rate tile should be where it was.  If it is missing from your dashboard, tap on the Discover icon > Health & Fitness Stats > all available tiles are there.

The Premium subscription does not give you a separate sleeping heart rate.  One of the metrics that goes in to the Sleep Score is call Restoration by Fitbit.  It is a graph of your sleeping heart rate measured at one minute intervals.  The Restoration score comes from how much time your sleeping heart rate is below your resting heart rate.  Here is an example:

My RHR is 47. Yes, it can be in the high 30's in my sleep.

Fitbit does use HRV, both to detect sleep and to estimate sleep stages.  Does this answer your question?

[SteverinoLA]

Hey LZeerW.  I have the heart rate tile on web and in app, but it seems Fitbit removed the 24 hour graph showing daily heart rate in 5 min intervals.  It's still in the web interface:

but now gone from Android app as far as I can tell.  Presumably now replaced w/the restorative heart rate graph you show that's only visible w/premium subscription.  I definitely used to have that graph you show b/c I would use it to confirm when I would awaken to go pee (you can see those little nighttime blips in my graph above).

1) So this question still remains -- did Fitbit remove this graph of useful info and now put behind this premium paywall?

2) Are you sure about HRV employed by Fitbit devices?  I referring to heart rate variability -- the variability of the time b/t individual heart beats.  The more variable the better.  It's the standard for measuring recovery.  This would be measured by heart rate sensor, not the SpO2 sensor I think.  Previously, Fitbit only measured it for the Relax function on devices.  Oura ring as well as Garmin wrist devices measure it continuously to report their "ready" scores for the day.  Oura ring is current standard for measuring HRV but was hoping Fitbit could come close to I just need one device.

[LZeeW]

@SteverinoLA   I am positive that Fitbit uses HRV.  It is mentioned in this Help article about Sleep Stages.  I am an iPhone user and have the 24 hour expanded heart rate graph in my app.  Here is Today:

Today

I got here from the usual Heart Rate tile > today's graph > expand.  This is gone from the Android app?  If it is gone, then it is a bug -- this graph is not behind a paywall.

You are correct about HRV and the Relax feature.  There is respiratory variability in the R-R interval.  Fitbit uses this to differentiate between inhaling and exhaling.  The Sp02 is not used.

[SteverinoLA]

Whoops, brain fart.  Yes, I have that graph so it's still there.  And I see in that article that Fitbit does measure HRV for sleep stages.

1) But can you see your HRV data somewhere in Fitbit world and is it a factor in the Restoration Score?  

2) How does your Sleeping Heart Rate graph shown in your 1st reply above compare to your Daily Heart Rate graph shown in most recent reply?  Shouldn't they be identical other than just being far more precise (is it 1 min intervals?) for the sleeping graph?

[LZeeW]

@SteverinoLA   Fitbit doesn't give you any interpretation of your heart rate variability.  From what I see, it uses HRV to estimate sleep stages and to guide your breathing while using the Relax feature.  The Restoration score appears to look at two things, the percentage of time your sleeping HR is below your RHR and what percentage of your sleep time is spent as Restless.  This is all very new, so I still don't know how how much each factor plays in to the score.

It's hard to put the sleeping heart rate graph over the daily heart rate graph, even to eyeball it.  The sleeping heart rate graph crosses midnight.  You can scroll the daily heart rate graph from day to day, but there is that midnight gap.  The daily heart rate graph is smoothed out, due to the sampling frequency.  Another issue is trying to compare them is that the "expanded view" does not go into landscape view.

I am happy to provide you with other insights.

[SteverinoLA]

Ha, I always spend hours in search funtion here trying to to answer my own questions.  You've already nailed way more real info in just this thread.  Thanks, you're awesome!

That article about sleep stages is the 1st time I've ever seen Fitbit mention HRV since I've been around for couple years.  Previously, they said sleep stages were calculated just based solely on heart rate and movement.  Hopefully, more info will come out on how exactly Fitbit now uses HRV measurements.  

Ultimately, I think I just need to accept two devices -- Fitbit to track my activity and an Oura ring at night to track and report my recovery, including HRV. 

I try the out the Premium week trial shortly.