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Using Heart Rate Variability as a measure of "biological age" (and the Palo Alto Longevity Prize)


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Hi guys hope you dont mind me joining you as I'm really intrigued  as to what your thoughts are on all things HRV and autonomic function,as I dont know anyone who has used these devices, online or otherwise.To be honest my main goal is to improve my running  aerobic function rather than live to 120 but if that happens due to improved aerobic function  so be it,and if a study comes out saying lying in bed all day adds 30 years to your life,you're on your own guys. :)xyz


Although I religiously take my HRV reading ever morning,it's my walking speed at  say 80bpm that I am more concerned with.If it has regressed from 15mim/mile to say 15:30m/m I change my regime and take things easier.This I feel is more accurate than any single HRV reading.Testing myself at a low heart rate is giving me feedback about my health,and testing myself at a high heart rate is giving me feedback about fitness.I have tested running pals and at times have found that their fitness was improving and at the same time  their low heart rate speed was regressing which eventually leads to a physical injury or 'chemical' injury(cold and flu etc)


You also have to remember that an HRV score in my case today for example was 66 standing 78 sitting is different to my 66 score  in January.I averaged 11mim/59sec at 126bpm this morning but in January 13min/15sec at 126bpm was my pace .I'd like to think I have improved but HRV tells me nothing has changed.So not really sure about certain things,maybe you have some thoughts on that?


Im not sure what the scoring scale  is with elite but with ithlete its 20x Ln RMSSD for my age(55) average  HRV score  is 59 with upper limit being 75 and lower 45.

 I think its when one reaches 70yrs that we have a chance to slow down decline if not raise HRV as thats when most of us stop working.


Hope this helps




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Hey Leo, good to see you here, I was hoping you'd join in!  Unfortunately I don't think there are any HRV experts in our group, and you probably have more experience with HRV tracking than anyone here...  That said, I've been doing a lot of reading lately, in part thanks to info that you provided on the CR Society Facebook group.  


I've been thinking a lot about cardiac coherence, and I will be posting a lot more about it after I receive my device and do some work with it as well as additional review of the scientific literature.  The basic plan will be to use one of the many paced breathing apps in conjunction with HRV measurement (or if possible, both with a single app).  Richard Gevirtz described (in the quantified body interview 'Heart Rate Variability Biofeedback as a Tool to Reduce Stress') how he finds a person's ideal breathing cadence in his practice (the ideal pace varies from person to person). I found an android app called "Paced Breathing Pro" that does everything I want for paced breathing including vibration notification and ability to vary inhale/exhale times as well as hold times at top and bottom.  I will go through a wide range of breathing styles and paces while simultaneously measuring HRV, with variations on breathing cycle duration, percentage of time inhaling vs. exhaling, and time holding at top and bottom of cycle, sitting vs. standing vs. laying down, etc. It will require a lot of careful data collection and time, but should ultimately allow me to optimize my HRV through meditation/breathing which supposedly can result in health benefits such as improved immune function and mental states although I still need to read up more on all of that and separate science from fiction.  Also note that Leo found Heart Rate Coherence Pro which may do both the breathing guide and HRV measurements in a single app, I'll have to explore that.


The Elite HRV FAQ has some relevant Q&A.  First, about how to do our "standard measure" - the giant data review that Elite HRV just posted about was based on what they call "Morning Rediness Readings" so I think our group should use the same standard for comparison purposes. This means taking readings first thing when you wake up, before getting out of bed, while just breathing naturally.  Of course all sorts of other readings will also be very much of interest within the group as well, I just think it will be good to have some baseline apples to apples comparisons particularly if we are trying to figure out how lifestyle factors and interventions influence HRV (and aging by extension). 


Q: Why is it important to measure HRV (Morning Readiness) in the morning instead of other times throughout the day?

The best way to determine your individual heart rate variability and thus nervous system activity is to take a short (1-5 min.) reading each day. Ideally you want the reading to happen at the same time, in the same way, so as to eliminate as many affecting variables as possible.

Throughout the day many factors can affect HRV. Internal processes like circadian rhythm and hormonal fluctuations cause it to slowly rise and fall over 24 hours. Also whatever you were doing before taking a reading has a very strong impact on the reading. Mental, physical and emotional experiences all affect HRV.

This is why we recommend taking the reading each morning. When you have just awoken you haven’t had the chance to experience the stresses of work, school, or the day. Your circadian rhythm and hormonal patterns should be consistent at that time as they were the previous day. We also recommend that you breath naturally for the Morning Readiness and take the reading in the same body position each time.

By calculating your baseline first thing each morning, you can eliminate a lot of variables and highlight the patterns that matter most. This allows you to cut through the “noise” and get insights about how recovered you are and how ready you are to tackle the day’s challenges.


Q: How do you calculate the HRV score?

Our HRV score process is broken down as follows:

  • We capture the R-R intervals via the chest strap heart rate monitor.

  • We apply the RMSSD calculation. Root Mean Square of Successive Differences (RMSSD) is the industry standard, time domain measurement for detecting Autonomic Nervous System activity in short-term durations (5 minutes or less).

  • A natural log (ln) is applied to RMSSD. Since RMSSD behaves logarithmically, it is difficult to conceptualize the magnitude of changes as it rises and falls. Therefore, it is common practice in the application of RMSSD to apply a natural log to produce a number that behaves in a more linearly distributed fashion.

  • The ln(RMSSD) is expanded to generate a useful 0 to 100 score. The ln(RMSSD) value typically ranges from 0 to 6.5. Using over 1,000,000 readings from our database, we have been able to sift out anomalous readings and create a much more accurate scale where everyone fits in a 0 to 100 range.

In regard to converting ithlete to Elite HRV scores, it looks like all you'd have to do is divide by 1.298398835516739.  Both apps apparently just multiply ln(rMSSD) by a fixed constant, but Elite made an attempt to fit everyone into a 0 to 100 scale based on their database of actual readings.


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Quick update -- I was very excited to find my new wahoo tickr waiting for me when I got home from work tonight! I could not wait to try it, I took it out, adjusted the strap, lightly moistened the electrodes, and took a sitting reading while breathing normally. First - the led indicator lights on the unit work great, that was mentioned in the reviews -- a very nice feature. Second, it quickly and easily paired with my Android phone via the Elite HRV app. The result of my first readiness reading? I have off the charts good HRV, with scores exceeding the mean from the best group (18-25 year olds) in the Elite HRV data, and exceeding the best group (10-19 year olds) in the Umetani et al., 1998 data.  My ln(rMSSD) was 4.67 corresponding to a 72 score in the Elite HRV app (4.87 or 75 score laying down later after eating).  Note: the very BEST ln(rMSSD) from the Fontana CR group (including Dean) was 3.87, with a mean for that group of 3.58 - so if my number is accurate (which remains to be seen) and comprable (to their 24 hour measurement) then I have blown them out of the water (another benchmark that can't be used in favor of severe CR).


My readings may come as a surprise to some (it was a surprise to me) considering I do zero endurance training and only brief HIIT workouts.  It's looking good for cold exposure especially since I had been wearing a cold vest for an hour before doing the reading... I look forward to gathering more data and doing lots of experimentation. Can't wait to find out how others from our group stack up. Hopefully my initial readings were not flukes.


EDIT to Add: Did a sitting reading after cold shower + ice drink + cold vest and got my highest number so far, Elite HRV score = 81, ln(rMSSD)=5.27

Definitely looking promising for cold exposure.

Edited by Gordo
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Mine arrived today as well which is nice. It can sometimes take a long time to get things here in Alaska, so I'm glad I can join right in from the beginning.


I normally like to read things systematically so that I understand them as well as I possibly can, but I haven't had a chance to read up on HRV very much yet, so I only have a foggy idea of what we are doing and why it is important and how to make sense of it all.


I downloaded the Elite HRV app and the Wahoo TICKR synched easily. To test it out I took a "morning readiness" reading, even though it is about 8:45 p.m. here. I was sitting up and trying to breath normally but I notice that because I was being tested on something I don't think I was breathing normally. It felt a little like I was holding my breath or that my lungs were always a bit too full to be natural. I'm going to need to work on tricking myself into breathing normally.


If I understand the results correctly, it looks like my first initial test reading got an HRV of 59. Based on the charts above that looks about typical for someone my age (37). Nothing to get too excited about, but perhaps my HRV will gradually improve as I continue CR.


I haven't gone out and bought a CE vest yet, but I have been taking ice cold showers (no heat at all from start to finish) and finding I rather enjoy them, even though they are also a bit unenjoyable at first. I've also been walking my dog in lighter clothing than I otherwise would be, and riding my bike to work in the cold without heavy layers. So you could say I am dipping my toe into CE but not in a really deliberate or focused way yet. For the time being my focus is still on figuring out CR and how I want to practice it.


Okay, some quick dumb questions:


Higher HRV is better right?

For our little study we don't need to wear the monitor all the time right? Just a quick reading in the morning? Anything else particularly useful like wearing it while going for a run?


I will eventually do my homework on HRV, but for the time being I might need to lean on some of you who are doing a lot of research to digest it and share the main takeways. I hate mooching like that, but I'm excited to learn more and see what we discover.

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Hey Gordo thats great news,way off the chart is a brilliant score but how are you going to see any differentials if you take a reading with a cold vest on sitting down .Holding your breath also gives a high hrv up to a point.


Lets not turn this into a my hrv is better than your hrv,its all about being able to measure differences in your ANS and where can you go after 'way off the chart'? With your protocol you will be getting oversaturated with your parasympathetic system ,it would take an earthquake to stimulate a sympathetic respone :0)

You have to ask yourself was everone else on Elite wearing a ice jacket to make reliable comparisons with.

In order to keep it like for like probably best to take it as soon as you wake up preferably after cortisol has subsided rather than exactly same time .

Circadian and hrv


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I got mine yesterday too.  I also used the EliteHRV android app, my initial sitting value was 35, but increased to 50 while doing paced breathing.  It was low 20s for most of my 20 minute hot bath at 116F, but at the end when I submerge my head twice for 20 seconds each time while holding my breath it fell to 1 and my pulse hit a peak of 170 - roughly max heart rate for my age.   I wonder if that is typical for HRV to fall to 1 at max heart rate?  While sleeping my pulse averaged 58 and I awoke in the middle of the night with an HRV of 60 but it fell back to low 30s as soon as I got up.


Due to the intensity of yesterday's work out I skipped this morning's workout and my cold bath, but I will use it for my next workout and cold bath.  I've also just begun practicing relaxation/meditation and I think this might provide useful feedback if a deeper state of relaxation results in higher HRV.

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@Gordo, I'm curious if your initial reading was a fluke or if you've been consistently in that same range so far.


I've only taken four morning readiness readings so far, so it's not enough to really tell what my baseline is, but I was pleasantly surprised that this morning's Elite HRV rating was an 81. I had gotten by far the best sleep I've had this week last night, so maybe that had something to do with it. Otherwise I have two readings at 59 and one at 66.


I'm also having fun learning about the sympathetic and parasympathetic measurements. The first morning I was mildly sympathetic. Later that day while I was biking to work I took a corner too fast and ended up crashing. Not seriously hurt, but with some nice road rash. Since then all my readings have been parasympathetic. I might be trying to over-interpret this given that there are so many factors at play, but it would make sense if I'm doing a little bit of healing right now.

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Hey Thomas, yes, I think its best to gather lots of data first before trying to come to any conclusions.  And Leo, thanks for that study, it is very useful to see some normal circadian fluctuation data as it relates to HRV (and melatonin).  I am definitely a "weird" case, as I do mild cold exposure pretty much all day every day, EXCEPT when I sleep.  This is just an odd ball long term personal experiment I have chosen to do.  That said, so far my lowest readings seem to come when I first wake up, which probably corresponds best to what my HRV would be without CE.  Clearly there is pretty wide fluctuation of values throughout the day as documented in the study Leo posted.  I think the only way to do meaningful analysis might be to do 24 hour readings (like Fontana did with the CR group).  I'm not sure how practical that is with our devices, but I'll play around with it...  (I guess taking a reading every hour while awake might be a decent approximation as well).  Also not sure that an elevated HRV caused by CE implies any particular health advantage, it could be meaningless, it is interesting to me though that the link exists and reminds me of "Dean's Law" which states that everything associated with good health and longevity is in some way connected to BAT activation.


I took a whole lot of readings today while doing different paced breathing exercises (you can actually do this all within the Elite HRV app itself by the way, it just doesn't have as many options for customizing the paced breathing, basically it only lets you choose how may breaths per minute you want to do, at 0.5 breath intervals.  I feel like I need to do this a few more times before gathering "actionable" insight.

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This thread looked interesting enough that I ordered a TICKR too.  I'm probably a bit of an outlier, since I'm a 65-year-old who picks through CR practices and discussions like it's a buffet, adopting things that look interesting without having ever followed a strict CR routine (too nervous about BMI dropping too low at my age).


I do cold exposure and TRF, though, exercise for a minimum of 4 hours per day (just over half of it walking, the rest a mix of resistance, flexibility, and balance exercises).  My TICKR should arrive in about a week.  If I'm not entering too late, and y'all think the data from someone of my hybrid regimen would be useful, I'm in.

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Welcome Larry, sounds great.  I think our whole group is just one big collection of "outliers" haha!  My thinking is that perhaps with enough data we can sleuth out some factors that may improve HRV (and longevity) based on the practices that we follow.  I'm not sure we'll have enough data points to do that but I think it's worth a try.  In the very least, it seems to me that tracking your own HRV daily has value for general health monitoring and even early diagnosis of disease (more on that later).


Early in this thread I linked to part 1 of "hrvcourse", the other 2 parts are just as important and informative.  Here is part 2:

HRV Demographics, Part 2 – Fitness Level

One of the friendly debates I've had with Dean and others is the anaerobic vs. aerobic approach to fitness.


"Generally, a higher Heart Rate Variability is correlated with increased aerobic fitness, and vice versa. This makes perfect sense since it is well established that regular aerobic physical activity can improve cardiovascular function and health which is measured indirectly through HRV. Many studies have shown that the intensity, duration and frequency of aerobic training are directly related to HRV changes. This is why HRV analysis with respect to physical training, especially aerobic physical training, is an increasingly popular technology used by elite and recreational athletes to achieve an edge... an active life pattern can be effective in diminishing the decline of HRV associated with aging"




"The good news is that in many of these studies, the activity level required to gain the significant health benefits as measured by Heart Rate Variability is only light to moderate. In the menopausal women study, the significant HRV improvement for the active women was seen at just light to moderate activity like walking three times per week for hour long sessions.

Both of these studies suggest that regular physical activity in the older subjects tended to reverse, to a degree, the aging effects on cardiovascular health such as vagal tone decline."


What about athletes?


No surprises that "significantly greater Heart Rate Variability was seen in trained men and women at rest, likely due increased vagal tone and parasympathetic activity and reduced sympathetic activity".

But what about 

Endurance-Trained vs. Power-Trained Fitness?

"Although less studied, the available research shows HRV effects on anaerobically trained individuals in power sports to be similar to those of aerobically trained athletes (Berkoff D J et al., 2007)."


In a study comparing 145 elite track and field athletes at the 2004 Olympic Trials, Berkoff et al. found that there was no significant difference in Time Domain and Frequency Domain HRV values between the endurance athletes and power athletes for both genders. The aerobic athlete group consisted of runners training and competing in 800m or longer while the power group included sprinters and athletes competing in field events that require more anaerobic training such as weight training and sprinting. From the results, they concluded that aerobic and anaerobic training leads to similar responses in Heart Rate Variability.




"The study hypothesized that the lack of differences in HRV may be based on “autonomic benefits of anaerobic training.” It is possible that the autonomic cardiac changes that result from anaerobic training are similar to those seen with aerobic training."


I thought this warning was interesting:  

"Be Careful: It is important to point out that elevated aerobic fitness can also have a downside. Since it has such a potent effect on Heart Rate Variability, it can actually mask underlying health issues"




In general, increased aerobic and anaerobic fitness significantly increases Heart Rate Variability. This is because increasing activity level and fitness increases autonomic activity correlating with increased ability for the body to regenerate energy, repair tissue, and more capably respond to both physical and mental stress.

Fitness levels that are required for health improvements do not require high volume, repetitive endurance sport training. An active lifestyle consisting of light to moderate activity (either aerobic or anaerobic or both) has shown to be sufficient for health benefits to reverse age-related HRV decline. Improved fitness beyond an active lifestyle increases Heart Rate Variability indices but it is not clear if those increases correspond to improved health past fitness.


I would add that both CR and CE apparently boost HRV, perhaps even more so than exercise.  I'm still gathering data and watching trends, but many of my readings seem to exceed that of even elite olympians despite the fact that I work out for only minutes per day and do no endurance training at all.  This is of keen interest to me, but who knows if it's meaningful or not...



Edited by Gordo
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  • 2 weeks later...

Sorry I'm late to this thread. A link to an episode of the podcast The Quantified Body (episode #35) was made earlier. It should be noted that this podcast has several episodes on the subject of HRV. See the list of episodes on Damien's website. Episodes specifically devoted to HRV are (so far): #1, #6, #8, #11, #20, and the previously linked #35. #20 is an interview with the longevity prize funder himself and specifically talks about the use of HRV as a biomarker of health/longevity (and is a short episode) and why it was chosen as criterion for the prize.


I'm a bit disappointed Damien didn't press Joon Yun in that episode on what seems like the obvious most important question about using HRV as a long-term general health biomarker: How is doing so appropriate when the HRV values jump around so much in response to other transient things, as aptly demonstrated by all these other episodes that are using it for other things. Eg, athletes find that drops in HRV are good signals of overtraining or temporary illness that might make them want to back off training for a bit (episode #1 of podcast). Others use HRV as a stress-level indicator and can see immediate drops just by thinking about stressful things in their lives (episode #6). There are variations depending on lying vs. sitting vs. standing, etc. These temporary confounders make it seem trickier to use HRV as a marker of long-term health / longevity / mortality predictor (whether in lab animals, as for the prize, or in us for our own health optimization).


At the very least, one wants to measure consistently (same position, time of day, etc.) and other practical tips are to try not to think too much about life or the upcoming day when doing a measurement in the morning. But even with those consistencies, to use it as a long-term health measure one has to do some kind of aggregation over many readings to get rid of transient effects. I didn't see any discussion of the right aggregating math function. Is it better to take average, or to use the highest (best) reading over a given timeframe (a month say)? That depends on which causes more fluxuation: transient drops from things like overtraining, stress, or temporary illness (colds/flu), which would argue for max, or random inconsistencies of the readings that might cause spikes that aren't real, which would argue for some type of averaging. I don't know.


More in a minutes. I'll put in a 2nd post.



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It should also be noted that Polar Heart Rate monitors have for years had a function that uses HRV to give a resting-only test estimate of VO2max. HRV obviously correlates with cardiovascular health, which in turn also correlates with biological age, but I think most of us would agree that VO2max while generally declining with age is not by itself the best biomarker of biological age.


So I'm skeptical that HRV by itself is that useful of a bio-age marker. Though it does seem likely to be useful for dealing with the transient things mentioned above (picking up illness faster and more precisely than fever or resting HR for example, or for helping to figure out what stresses you in life or as a biofeedback marker to get better at meditation for example).


There is a lot of work exploding right now in the aging biology world on coming up with better bio-markers of biological age (or mortality prediction). DNA methylation (aka epigenetics) is a hot area for this right now (see for example the publications of Horvath and those of Hannum), though the issue is that the tests are expensive currently (and not easily available direct-to-consumer). Lots of people are trying to use machine learning ie statistics (in many recent cases the latest buzz-fad subtype of model called "deep learning" neural nets) to predict biological age. Examples include how-old.net (age from a face photo) and aging.ai (age from simple blood test values). Also notable is the recent publication of the different rate of underlying biological aging of a cohort of (at the time of publication) 38-year-olds, which I'm pretty sure was discussed on these forums somewhere, which was based on many different measurements though IIRC they didn't release a model that other people could plug their own numbers into.


I'm confident these kinds of efforts are fairly quickly going to come up with things that are better predictors of overall health/mortality than actual chronological age or just-HRV.



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Hi Karl,

I judge my hrv by a monthly rolling average and its a great aid in determining whether you're stressed or not and changing the things you can change which hopefully counteracts the stresses you cant change.

I take mine every morning standing up as ive experimented with supine readings which for me unfortunately my parasympathetic systems floods the reading.There are lots of variables that can affect readings which for me makes it more relevant and interesting.Its not as simple as watching what you eat,which is the easy part.Its all about balance.You dont see many stressed centenarians

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Leo- I am also really appreciating the value of daily HRV tracking.  Today is a perfect example, I woke up feeling "normal" but my HRV score showed a substantial drop.  This is a signal for me to be careful, and to recover, which is what I tried to do today, though as the day went on, I could tell my immune system was fighting something (which happens a lot when you have 2 young school age kids and a school teacher wife).  This is even more valuable to someone living an obsessively healthy lifestyle, because we don't get the typical symptoms when our immune systems are fighting something, the only symptom I seem to ever get is feeling tired or "off kilter" (I haven't had a fever, sore throat, cough, headache, or runny nose in years).


At any rate, I can't remember now where I saw the following link, but I searched the forum and couldn't find it.  This is an interesting TEDx talk someone recommended, and deserves to be in this thread.  

TEDxPortsmouth - Dr. Alan Watkins - Being Brilliant Every Single Day (Part 1)

He starts talking specifically about HRV around minute 13 after quite a long build up for the TED format :).  He says something to the effect of: HRV can tell you when you will die, it can tell you how much energy you have, but the real reason his clients are interested is because HRV can alter brain function. Then he actually hooks a volunteer up to a heart monitor and does a live demonstration of this.




"Your biology is controlling your brain function" In part 2 he does a live demonstration of how controlled breathing can boost HRV and "switch your brain on" making you more perceptive, insightful, etc.  "Rhythm and smoothness gives you the most powerful effect." Put your attention while you are breathing on the center of your chest and focus on the energy of your heart, this causes you to drift into a more positive state:






Through the


Every day


However this only gets you to the midpoint of where you want to be.  To take things beyond that you must learn to regulate what emotional state you are in.

Edited by Gordo
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  • 2 weeks later...
  • 2 months later...

Temperature seems to have a big impact on HRV.  As I posted before, a very hot bath readily drops my HRV to 1.  Previously I speculated a connection between pushing heart rate to max and an HRV of 1, but since have achieved an hrv of 1 at heart rates well below max and have managed a little hrv, as high as 10, when hitting max heart rate.


On the other end, cold dramatically escalates hrv.  Here is this morning's reading taken at 62F.  And this is after a brutally intense workout the day before yesterday that I'm not fully recovered from.


hrv 89, hr 61.96, min hr 28.00 max hr 127.66
rmssd 322.65, lnrmssd 5.78, sdnn 299.20, nn50 83, pnn50 60.145
Anyone else noticing a dramatic rise in hrv with this chilly winter?
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Yes, I have noticed, cold dramatically boosts HRV.  It would be interesting to learn more about why and what the mechanism is and if higher HRV induced this way actually has any health benefit in-and-of itself or not...

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  • 3 years later...
On 9/19/2016 at 4:08 PM, Gordo said:

My readings may come as a surprise to some (it was a surprise to me) considering I do zero endurance training and only brief HIIT workouts.

This might explain it:

Genetic influences on heart rate variability

The results showed that variability of HRV and HR measures can be accounted for by additive genetic and non-shared environmental influences (AE model), with no evidence for significant shared environmental effects. Heritability estimates ranged from 47 to 64%, with little difference across HRV measurement domains. Genetic influences did not differ between genders for most variables except the square root of the mean squared differences between successive R-R intervals (RMSSD, higher heritability in males) and the ratio of low to high frequency power (LF/HF, distinct genetic factors operating in males and females). The results indicate high phenotypic and especially genetic correlations between HRV measures from different domains, suggesting that >90% of genetic influences are shared across measures. Finally, about 40% of genetic variance in HRV was shared with HR. In conclusion, both HR and HRV measures are highly heritable traits in the general population of young adults, with high degree of genetic overlap across different measurement domains.

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  • 3 years later...

I'm resuscitating this topic after having read the thread on coffee.

Recently there has been a lot of talking about HRV, especially so after the popularity of this measurement in wearable devices. I read about Gordo's extremely high values, are they correct, have you double checked? an RMSSD of 195 (ln(RMSSD)=5.27) is an outlier and it is not known if it has a specific meaning related to health and longevity. The default value in EliteHRV is not ln(RMSSD)but ln(RMSSD)*k, where k is an unspecified multiplier.

Also, there is not very much definitive presently known about HRV, if not that one's personal trend may suggest deviations in the activity of the sympathetic system, and that too low a value may be unfavourable but many people with a low HRV value have no health problems.

So far, HRV seems to be in practical use mainly by professional athletes, although with the latest wearables a number of algorithms on stress and recovery, based presumably on HRV, have proliferated.

The allegedly best way to measure one's HRV without the risk to incur confounding factors would seem to be a short (2 to 5 minutes) morning measurement, just after waking up. All night measurements as done by wearables may result in some unreliability if taken in intervals and not continuously. 24-hours measurements are downright impractical.

I also read Mike Lustgarten's thread on his personal trends in HRV and the meaning he attributes to them (OK lower HR if paired with higher HRV).


Edited by mccoy
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  • 5 months later...

Long time I was not curious enough to invest time into the topic but winter boredom forced me to find a new toy, so I decided to buy something compatible with elitehrv and I decided to give a try to an old arm tool scosche rhytm24. I am skeptical about non-ecg methods of measuring the things but scosche's tool seems engineered to overcome the issues typical for led measuring tools due to another wavelenght led in addition %). In any case, within hr mode it is pretty accurate, the same as my old analogue sigma strap, no idea how good it is in hrv mode, I have no polar or at better Holter to test against.

I am now in the middle of a dedicated book on the topic https://books.google.com/books?id=f368BAAAQBAJ&pg=PA129&lpg=PA129&dq=DOI+10.1007/978-1-4471-4309-3_6&source=bl&ots=dsnoJ_DF55&sig=ACfU3U2mcRG-wEWWpu4mfHmRW7jasTzjKA&hl=en&sa=X&ved=2ahUKEwjCrPrhtqWEAxU0GhAIHXpSDYwQ6AF6BAgLEAM#v=onepage&q=DOI 10.1007%2F978-1-4471-4309-3_6&f=false

and what could I say - it is freaking complicated to both understand how to use it and to actually use it for own purposes.

IMHO this is an area to be used by researchers for looooong time (and is being used actually for decades but without wide attentiion) until something could be figured out based on it. EliteHRV's method of taking morning readiness check in a stationary position and then calculate some aggregate based on some formula is the most close way to use the things by non-professionals but even this approach at least in my case is questionable. Here are my trends for one month, maybe at the beginning there is some mangling data from tries on a walk, one time random shots etc, but most of the data comes from readiness checks. The context - I am pushing down the calories slightly, slowly decreasing resting heart rate and still weight stable (not sure this will not start to move). Also according to CBC I am balancing at the low (technically it is anemia but I am not suffering from symptoms).


The most interesting for me in my figures is that they are moving like insane and it is funny to map them onto studies of particular things like "SDNN less than 50 is more risky than 100+", "LF <300 is risky and >500 is good" etc. I have no idea how to derive something from this stuff, maybe much longer sequences have to be collected but I am not so stable - I change my lifestyle as year moves and this changes a lot of things so perhaps all this stuff will be just a toy in my case. But the math behind it and theoretical assumptions are still a good food for the mind so I hope to continue to play with it %)




Edited by IgorF
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If somebody has time to play on a low budget with non-optical measurements there seems an option - Kardia's raw data files could be analyzed after conversion via vendor's tool https://www.alivetec.com/pages/research-tools but rooted device is needed. Maybe paid users can do from the website like described but my acc has no data there, so only messing with device rooting could help.

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