Inspire 3 is not tracking my heart rate accurately

[FrankieFireFly]

Hi all,

I recently bought an inspire 3 and was excited about the health metrics. I’m female, 44 and fairly fit/active - so have a resting heart-rate of about 58 to 62 (which is very good/excellent for my age apparently). However my HRV is in the 20’s!!! Which is pretty odd (and ironically I do lots of work around wellbeing). Just wondering if others have found this - from what I’ve read those who are more active (eg joggers) are noting this. Please confirm - or otherwise - as I’m curious.

Moderator Edit: Clarified subject

[MarreFitbit]

Hi there, @FrankieFireFly. Welcome to the Fitbit Community Forums. Thanks for the details provided in your post about the accuracy of your heart rate on your Inspire 3.

Heart-rate variability (HRV) is the variation in time between heartbeats. If your heart rate is 60 bpm, your heart doesn’t necessarily beat once per second — a healthy heart isn’t like a metronome. Your autonomic nervous system determines the timing of each heartbeat.

HRV varies from person to person. Studies show that people with a higher HRV have better cardiovascular fitness and might be more resilient to stress. Mindfulness, meditation, sleep, and physical activity can help improve your HRV. A significant drop in HRV may indicate that your body is experiencing illness, stress, or depression or anxiety.

If you haven't done so yet, please see What factors can affect my heart-rate reading on my Fitbit device? 

See more tips in How do I track heart rate with my Fitbit device?

[FrankieFireFly]

Thanks Marre,

I actually do much research into HRV and wellbeing (some has been published in PLOS One) - but I’m curious about the accuracy of it - especially when taken overnight. I couldn’t find any published papers on Fitbit devices and HRV (especially using night time HRV as a valid indicator of HRV)

Typically, we use HRV to understand how well individuals respond to a stressful situation in the day (and over time) because that is when you have more variation between your SNS and PNS - if coping well (eg when subjected to day time stressful events). So I’m wondering how accurate the Fitbit metric is - as it’s calculated overnight when sleeping. Also my results don’t reflect a sudden drop but a very, very low baseline -  a baseline established when one is sleeping. That is why I wondered if it could have something to do with general fitness.

If you can point me to any published research around fitbits and HRV please do. As if the wearable technology is accurate that is great!

[lmacmil]

Where is HRV shown?  I see resting heart rate (mine is 51 to 55, a result of being a runner/jogger for almost 50 years) but I can't seem to find HRV either on my dashboard on the website or on my app (Apple).

[FrankieFireFly]

Hi,

You should be able to update your Fitbit App and then see a new metric called ‘health metrics’. In that section you will see HRV, oxygen saturation, body temperature …and after a few days of collecting baseline data these indices get populated. I hope that helps. 

[lmacmil]

Thanks.  I had to add it to my home screen.

[FrankieFireFly]

That’s great.

When it starts to work, let me know your HRV readings. Mine are so low, I could theoretically be in a coma! 🤣

[lmacmil]

Mine has ranged from 22 to 28ms over the last week.  Apparently that's quite low but I am in excellent health and aerobic shape so I'm not going to worry about it.  Plus I don't think the Fitbit is anywhere near as accurate as an EKG would be. 

[FrankieFireFly]

Thanks - that’s interesting as mine ranges from 17 to 27!!! So for someone in their 40s very low. I’m not convinced it’s accurate because if you have a low heart rate generally that also means your Parasympathetic Nerve System (PNS)/vagus nerve is working well (as it acts as a break to the Sympathetic NS ‘accelerator’). Without the vagus nerve your heart would beat at circa 120 BPM.

In high stress situations you should have high HRV as it means you have more control of SNS via PNS …but overnight fitbit is working out HRV when at rest …and as I understand it SNS activity from when in REM sleep. So not really rest vs. stress.

My thought is this metric isn’t accounting for individual differences and those who have a very low resting heart rate - which indicates good PNS/vagus nerve control per se. Although this is at present speculation/a hypothesis 🙂

[lmacmil]

Apparently HRV decreases with age.  I'm 74 so mine appears to be at the very low end of normal for and old guy!

[FrankieFireFly]

That’s good …but doesn’t appear to fit with your general fitness for your age 🙂…

“Reduced HRV, which reflects sympatho-vagal imbalance (i.e. increased sympathetic or reduced vagal activity), is associated with cardiovascular risk factors such as physical inactivity, hypertension, and diabetes (2–4), and cardiovascular disease (CVD), itself (5).”

…which is why I don’t trust this fitbit metric 👍

[lmacmil]

Wow!  I had over 16,000 steps yesterday which included a 25 minute run (2.5 miles), mowing the lawn, and a 30 minute walk in the afternoon.  Admittedly that's a high day for me but I usually average about 10,000 steps/day.  My BP is normal, I don't have diabetes or CVD and I'm certainly not physically inactive. 

A friend got a high heart beat warning from her Fitbit last winter and spent several hours in the ER (mostly waiting to be seen) only to be told they couldn't find anything wrong. The Fitbit is not a medical device.   I'm going to remove HRV from my metrics. 

[FrankieFireFly]

I think I might too 🤣! I average about 90,000 steps per week and am generally fit and well (with no health problems) and a resting BPM of circa 58 to 60. So I’m not convinced by it 👍