How often does it read heart rate? Does the graph just show an "average" HR?

[WarpedTrekker]

I'm wearing my Charge 3 at night, and it appears from the graph, that each reading is 5min apart. Is that correct? It takes a reading every 5min? If that is correct, does it average out the heart rate over the last 5min in the FitBit app, or does it show the reading as it was just taken?

Also, if I look at my watch at any time, is the heart rate that is displayed, the real-time rate, or is that an average of the last 5min?

I have another device that measures HR constantly over night, and it showed my HR dropped down to 45bpm, but the Charge3 only shows I was at 60bpm during that period. So I'm trying to determine what device is correct.

Also I know for a fact last night, my HR jumped to over 100bpm+ due to a panic attack for a minute, but the FitBit didnt register anything above 90bpm. So this is why I'm thinking the FitBit is doing some type of averaging instead of showing actual heart rate on it's graphs.

[WavyDavey]

Hi @WarpedTrekker ,

You are correct.

The Fitbit takes readings more often, but what you're seeing in the graph is the five-minute average from those readings.

What you see on the watch is a real-time view of the heart rate.

Because of the averaging, it's possible to see a high reading on the watch real-time, that doesn't show up on the graph because it's averaged out.  Hope this helps.

[WarpedTrekker]

Thanks. Is there any way to get a more defined detailed graph that doesn't average? This is easy coding to add to the software. 10sec averages would be more acceptable and useful then showing only every 5min. People with heart conditions need to keep tabs on what their exact High and Low heart rates have been during the day. Averages are not helpful. 

Today I tested it by going up three flights of stairs and the graph only showed I peaked at around 100bpm. But I immediately took a reading with my Samsung S10 sensor and it read 135bpm which is much more accurate to what I was feeling as I felt my heart racing much faster then 100bpm.

This is unacceptable accuracy in the graph. Same thing when sleeping. I have episodes where my heart has gone down to 45bpm when measured with other devices like an oximeter, but due to the averaging in the fitbit graph, it shows my lowest heart rate of 65bpm. 

I would like to see more granularity in the graph where you can zoom into the time. If the watch is actually taking readings more often then it should sync all of them to the app not just average them out. 

I'm trying to keep track of my heart rate due to a medical reason but this device is unacceptable to do that. 

Also why fitbit hasn't added HR notifications for too low or too high of HR? Samsung Active has that feature and  also Garmin and Apple Watch. AFiB and arrhythmia detection should also be added and I hope is added at some point in the near future. People have been asking for those features for a long time. 

[WavyDavey]

I agree that considering a fitbit to be a medical device is unacceptable. We're reminded often that they aren't medical grade devices, and not meant to diagnose medical conditions.

You can manually start an activity on the tracker, like Workout, and let that run for the duration of the exercise. There I believe it gets down to 1 second intervals, so even brief peaks and valleys should show.

[raleighfit]

The app Cardiogram works with Fitbit and has heart beats for every minute. I assume it is an average. A great app.

[Donxyz]

Good Answer I wondered about this for a while