Versa 2 heart rate variability

[rwahl]

Hey guys! I have two questions:

1. Why does the HRV only track when sleeping at night and not during the day at all?

2. What is a good range for HRV when sleeping? Mine is 20 every night and I have no idea if that is good or bad.

Moderator edit: updated subject for clarity

[SunsetRunner]

Good questions, @rwahl - You can find some detailed answers in this Help section. You can also find good information by checking HRV in the Health Metrics in your Fitbit app on your phone. Please check these out then let us know if we can offer more help on this topic.

[rwahl]

That help center area did not answer either of my two questions. It does not tell my why HRV is only tracked at night and not during the day, nor does it tell me the range HRV should be at. 

[t.parker]

@rwahl first about HRV. HRV is higher when you are relaxed. In sleep, it should be rather high. HRV of 20 is very unlikely to have unless you are older than 65 (if your profile picture is you then I highly doubt it). For my age (40) I get usually morning readiness HRV of 69-71. I don't know my sleep HRV, as I don't measure it (maybe one day I will). The number without the context doesn't say a lot. You need a lot more data to make any useful meaning out it. I check my HRV after cardio training, then one time it hit 27 which makes sense because my heart was beating like crazy and it indicates physical stress. However, higher HRV doesn't always mean better. What matters are patterns in R-R intervals which may indicate more stress either towards the sympathetic or parasympathetic nervous system. However, finding this out require lots of context and data. HRV may simply give you a vague hint of whether your body is in some sort of stress but just a number has very little meaning.

Now, measuring at night. It is Fitbit's usual practice when they don't want to reveal any data and methods. This is just my opinion, but for me, it shows a lack of confidence in the feature and its accuracy. You can't take another device that measures HRV using a chest strap or another dedicated device and test it side-by-side. I don't know what data you can see on Fitbit as a result (is it only HRV number, is it a graph?). Usually, optical sensors are not great at measuring HRV and I don't really believe that the Fitbit sensor is any different. HR sensors must be suited to measure R-R intervals and must be very accurate. For that reason, on my Fenix6 watch, I must use a chest strap to measure HRV (it doesn't allow me to use a wrist HR sensor for HRV). Same, the EliteHRV app requires a dedicated device and won't let you use a mobile phone HR sensor. HR is easy to measure. HRV is not. Fitbit's HRV is just a gimmick and buzzword but I wouldn't consider using it for any serious purpose.

[rwahl]

I only have my Fitbit that tracks a bunch of stuff for me, including HRV. However, It only tracks HRV during sleep and never during the day. I am 32, so hopefully still considered young. For last night it says my HRV was 20. It tracks my HRV every night as long as I wear my Fitbit to sleep. From September to today, wearing it every night, my lowest HRV is 20 and my highest is 33. It has never been lower than 20 or higher than 33 overnight while sleeping.

[Lecks]

Mine’s only about 20-25 too. I think that’s pretty low. I’m 59 but rate excellent in the other fitness categories so was a bit worried about the low HRV til I read this !

[sbruinsje]

I had the fitbit sense for a couple of weeks now and or me the hrv is mostly around 80, with the lowest 60 and highest 110. I already didn't know what to make of it but now i am reading all this it means even less to me.

[dorien11]

mine was 116 last night, seems impossibly high?

[elizabeth_jane]

Whoop has a good article on typical HRV ranges: https://www.whoop.com/thelocker/what-is-a-good-hrv/ -> you can find typical HRV ranges by age there. 116 is very, very good.

----------------------------------

20-25 is within the typical range for your age!

[Jason2020]

I've been looking more into this and my Fitbit Charge 4 gives me a similar reading of 23. It seems inaccurate either based on https://elitehrv.com/the-8-biggest-mistakes-made-when-measuring-hrv that states, "We regularly get the question of why heart rate monitors like the Fitbit Charge are not compatible for measuring HRV. The simple answer is that many of these devices are not intended for measuring the more detailed heart rate fluctuations needed to calculate true HRV. They either do not record the RR intervals (times between each heartbeat) needed to calculate HRV or they provide smoothed, averaged, or altered RR intervals that remove the variability that makes up Heart Rate Variability." It says Fitbit uses RMSSD or the root mean square of successive differences between normal heartbeats. According to the Whoop Strap chart below I should be in the 40 to 70 range. According to https://elitehrv.com/normal-heart-rate-variability-age-gender It seems like my score should be around 50. As you look at more studies here https://elitehrv.com/hrv-demographics-age-gender they find the Average male my age could be 32± 16.5. So if the last one is accurate I guess I am OK. Looking at the varied numbers maybe the higher ranges are from studies of people who use devices to monitor fitness on their own accord and therefor care more about there fitness and maintain a higher level of it. The last study was a 5 min EKG study so just the average person that may or may not work out. Last though is this website stating that HRV is supposed to be higher at night https://www.myithlete.com/how-your-hrv-varies-throughout-the-day/ Honestly IDK what to think except maybe I need to work out more during the day. This Covid living has me getting lazy. Also Fitbit needs to release more info on averages on their app so we can see how we compare (based on their measuring devices) to the average person our age and gender tested at night.

[daniel.manso]

I’m 41 years old, and my numbers are pretty much the same. It doesn't make any sense to me. It's just not precise data entirely out of context. Since I quit smoking and restart running, no changes in the numbers. It’s been six months until now.

Have no clue. Mine was 114 last night, and I'm 41. However, the previous night was 71. This seems to be a considerable variation without exogenous variables' existence.

Moderator edit: merged reply

[BlueCursor]

You are comparing apples to oranges. Fitbit Charge reports an HRV number in milliseconds. Other devices report an HRV score.  An HRV score is the millisecond value normalized with a logarithmic function and scaled with a number added to it to make it bigger. This expands the score, usually between 1 and 100. Different companies use a different formula to normalize the millisecond value. So unless you have an HRV in the original milliseconds, the score cannot be compared to HRV scores from other companies. 

[Laura321]

This was one of the best answers I've read on a community forum, Fitbit or other companies.  I have a Fitbit watch and wear it all the time and like the metrics on sleep, resting heart rate and step count,  but know that the step count can be effected by do many non-step movements (like driving in a car). Some of the apps are useful and convenient.  However,  I found that I can't use the HR feature for any kind of HR tracking that involves movement.  I use a Polar chest strap and the Polar app.  Polar was an early pioneer in making HR  devices (chest straps) and I started using them when they first came out.   I'd been using Fitbit devices for step counts for quite some time as well so when Fitbit came out with the 1st multifunction HR and step devices I eagerly bought in.  However it didn't take me long to realize the HR feature was nowhere near accurate except on very low to no impact activities   I haven't been paying much attentionthe metrics in the app and  just saw that HRV data is now available on my Versa 2.  I also wondered why the about more section says that higher HRV data is better but then didnt give any ranges.   I haven't ever tracked HRV and admit having a hard time understanding all that goes into it and Fitbit isn't making it any better.   I very much appreciate the info you provided and maybe I'll try some of the devices you mention or see what Polar has available to get more reliable data.  Thank you again.   

[tekitorch]

Mine was 11 - I guess I'm dead? 🤔

[Robert-H]

This is an old thread but I thought I would add my input based on what I have learned from using a Versa 2 for over a year and trying to track my health.  I stumbled across it after initiating a premium trial and trying to make sense of HRV.   

I can’t speak for the HRV device accuracy.  I have been frustrated in the past at my Fitbit device.  For example, several times my heart rate would be exceptionally high and restarting the Versa 2 would correct the issue.  Or clocking 10000+ steps over several hours driving a large truck over mountain passes. 

When I initially looked at my low HRV, I dismissed it as the device issue.  But after monitoring it for a few weeks, I am with @Scotty7991.  It is useful as a guidepost and not a measuring stick.  Also, it is a personal measurement and use it to track your lifecycle choices.  In another post, someone pointed to this article from WHOOP about HRV and how it tracks with age:

What is a Good HRV? | Heart Rate Variability | WHOOP

With changes to my diet, lifestyle, and especially changes to my sleep habits, it seems is it possible to improve your score.

As an example, my HRV score dropped after my Covid shots:

I track my sleep metrics in Excel and have also generally observed HRV tracks with nights of poor/good deep sleep.  When I have a poor night(s), it drops and improves on nights with a lot.  I have been working through snoring/apnea issues.

Also, I would check what you eat and drink.  I was concerned last Christmas when my resting heart rate jumped 10 points over the course of a week.  During that time, I at A LOT of Christmas cookie with refined sugar, drank my share of beer and wine, and stressed prepping for Christmas with two kids.  But I observed it also went back down after two weeks of improved diet, less alcohol, and some intermittent fasting:

Overall, I get light to moderate exercise.  My diet is whole foods with low processed ingredient and little alcohol.  For reference, I am 54. 

Hopefully, this post helps anyone following behind me. 

[Specky]

Appreciate this is an old thread but:

1. Why only measured at night? Because we tend to be still at night, and the sensor gets a more accurate reading.

2. Is your reading good or bad? It's low (= bad, sorry), but you're only in roughly the bottom third. There is a LOT of variation from one person to the next: at least, there is when Fitbit measures it. And 'bad' here shouldn't be taken too seriously. It's just one indicator out of many and not a reason to panic.

Chart A here tells you the typical range for Fitbit. Use the solid lines (06:00).

This study has the details: https://www.thelancet.com/journals/landig/article/PIIS2589-7500(20)30246-6/fulltext

[Robert-H]

Thanks for the link.  From the article, I am taking away exercise matters.  I am now on 46 consecutive days of 10000 steps.  I will up running/stairs to see how it matters.

[Pcmom114]

I must be dead too. Average 11-13.

[Robert-H]

A quote from @Jason2020's Link might be helpful?

When measured alone, without any other context, HRV tells you the general state of your nervous system and health but cannot tell you what is causing or affecting your condition.

Tracking HRV in conjunction with additional context such as energy levels, fitness tests, sleep quality, a food log, etc. can help you identify what specific lifestyle factors are most affecting your systemic health and progress.

[Lecks]

Thanks for your observations ! Yes it does seem to reflect my lifestyle
vaguely . In particular I get a better score on days I’ve done a big burst
of exercise and raised my heart rate.
Good to hear what you have found 😀