According to this independent study:
“The greatest degrees of confidence are extended to HRV4TR/ECG and OURA, as our data suggests they can most accurately report rMSSD”
“The Oura smart ring (PPG) exhibited better accuracy than all cECGs except for HRV4TR/ECG and the FSTBT (cECG) lacked in rMSSD accuracy.”
What I meant is that I arrived at the same ballpark numbers with both methods. So it was a confirmation.
Intervals.icu will now plot DFA a1 from that app. There is also a long thread discussing (among other things) how accurate it is:
Pay this man! Always coming through with the quick updates
Chronically low HRV? I’m 69 and recently discovered that I have chronically low HRV. I’ve been taking HRV readings for a couple of years, which were not low but those were taken with Wahoo Tickr and typically after a 10-minute guided mediation, which I now know raised HRV.
I received an Oura ring for Christmas and have been comparing the overnight reading with 4 apps (Elite HRV, HRV4Training, Kubios, HRVLogger) using a Polar H10. Are all consistently in the 17-21 ms for rMSSD. The good news is that the trend is what is important and a low HRV does not necessarily mean a low readiness score, as I regularly get good-to-go scores. But after looking online, the potential bad news is that a chronically low HRV predicts a higher risk of heart disease and mortality from several causes. https://www.ahajournals.org/doi/10.1161/01.CIR.102.11.1239 Although HRV does reduce with age, mine is lower than my average peers, according to EHRV charts. I wanted to throw this out for discussion in case others have a similar pattern and see if anyone has been able to raise their HRV. As for me, I follow all the recommendations to increase HRV, including good sleep, meditation, healthy diet, and (of course) exercise of around 100 miles cycling per week.
Biofeedback is said to increase HRV and the Elite HRV app has a built-in module for biofeedback. I plan to try that (20 minutes twice per day) and see if it makes a difference.
This was an interesting post from Alan Couzens. He is offering HRV guided personalized training for $20/week.
Now his active tweeting makes sense….nice side gig. He knows how to write code, so he can automate a good deal of the process.
If you have an Apple Watch, the new version of Sleep++ ( Sleep++ on the App Store ) is a good way of consistently recording HRV and getting a comparable “Whoop-like” recovery scores. I’ve been using the last few weeks and it’s pretty spot on. RPE is proportional to the score.
People using Elite HRV app which metric do you use that correlates with fatigue or just works fine for tou?
Not sure I completely understand what you are asking, but as an Elite HRV app user, I just track the main HRV and Readiness score it provides each time you take a reading and then track this in intervals.icu in order to identify trends etc… I find these main metric provide enough for me to form some opinions on how my training is affecting me over different timescales.
Hey guys,
I’ve been gathering my HRV data for the last 6 or so months (Polar H10 via HRV4Training). I’ve recently (starting in March) bumped up my training volume from average of about 8hrs per week to now probably 11 on average (peaking at 13 thus far), on my way to building my volume in the offseason into 2023.
So I’ve been looking more toward long term trends in HRV relative to baseline, and I’ve noticed something that doesn’t track with the FAQ and common misconceptions. Specifically, my HRV baseline will generally track in the normal range when I’m training my “normal” training week, 10-13 hours, 2 hard sessions, 2 long sessions, 2 recovery/technique/neuromuscular sessions.
It’s when I go to take planned recovery that my baseline falls below normal. It’s almost like my HRV data is telling me I’m better off not taking a recovery week. See below graph, a standard from HRV4Training Pro:
You can see there’s two times I’m “maladapted to training”. The first is near the end of March. This is after 3 weeks of my new normal… all throughout the actual block, HRV baseline is normal. It’s not till I took some structured time off that my baseline dove. (This also coincided with the advent of allergy season in San Diego, so the deload coincided with those allergies and about ten days of reduced volume anyway). So the dip there might make some sense given stress caused by the onset of those allergies.
The next dip starts, again, several days after a planned deload. April’s training went very well, nice ramp rate and then recovery and HRV baseline, again, below normal. “Maladaption to training” happening well after the actual training has backed off.
And now again, I’m taking a few days of easy before a racing block here, and my daily HRV has been below my baseline value for two days in a row. Not after Monday where I did a 20-min MMP test, but after Tuesday’s recovery ride, Wednesday day off, Thursday 90 minutes with a few openers of less than 30s… HRV below baseline and trending lower.
Physically, I feel fine. It’s possible there are stress confounding factors this week, but the April dip had no such confounding factors. I took three days off the bike, then a got back into my training.
So, the oddity here is that it’s almost like my body is in homeostasis when I’m training “normally”, even ramping as I was in March and April, it responds well until I shut things down.
My thoughts here are a couple:
(1) Perhaps the subsequent maladaption to training after planned recovery is time-late, or it is indicative that I’m not taking enough rest during my recovery weeks.
(2) This is just how the model works because it is a rolling baseline average? But even then, the acute, daily HRV trends show that when I take recovery days, my HRV ends up below baseline, and it returns to normal when I am training.
Perhaps I need to take a baseline during my offseason when I don’t train at all… I’ve not done that, but that’s two weeks out of the year, so it would seem less valuable to know what that looks like anyway.
Anyway, interested here if anyone has similar experiences, or if anyone has insights here. I’m admittedly relatively new to HRV, but looking at my trends in HRV4TPro today bounced off my training and subjective log, this was somewhat eye opening, and maybe, potentially, actionable in my planning and training execution.
Any thoughts? @marco_alt - free advice? 
I opened my 30 day free trial of the coaching account on Pro today after going back through some of the blog articles, and the dashboard and overall presentation of the data on Pro is great. I will be subscribing and using it for my athletes who track HRV.
(This also has me seriously considering an Oura for my upcoming birthday… not for the HRV, but more for the combined sleep and not having to measure every morning… recognize that there will be a new baseline required from changing over…)
I also plan on trying the test Marco wrote about in his most recent blog, one suggested by Dr. Seiler for testing HRV before and after long, “polarized” zone 1 sessions to see if they were easy enough. That seems like an interesting test to run prior to or in your prep and early base seasons.
Clearly a case of The Opposite:
I’m broken. 
But then after my particularly taxing workouts inside my training blocks, I do get a dip in acute HRV like clockwork… typical is Interval - Long Ride… and the day after one of those two sessions, I will usually be below baseline. But it comes right back up after the subsequent easier days and I’m ready to bang on again.
But if I shut it down for a few days and recover? Lord, my body hates me, apparently.
So, if I take 3 weeks off, and only train for one week, I’ll be awesome at bikes?
Do you get any additional info from HRV that is not given by RHR?
hey @kurt.braeckel, thank you for using our platform.
Interesting data here, I will try to address a few aspects, based on what I can gather from the description and what we normally expect.
As you say below, the relationship between the acute (daily) change and training intensity is typically quite consistent, but in the long run, this relationship between physiology and load changes.
Acutely, after an intense or particularly demanding session (e.g. one in the heat), we tend to see suppressions in HRV highlighting the disruption in autonomic activity that can last up to 48 hours. This is what we report for a broad range of individuals (N = ~30 000) in a recent paper: Sensors | Free Full-Text | What Is behind Changes in Resting Heart Rate and Heart Rate Variability? A Large-Scale Analysis of Longitudinal Measurements Acquired in Free-Living
The reason to use HRV and not just resting heart rate (@Vernix) is typically the higher sensitivity to these stressors. Changes in heart rate are often around 0.5%, and smaller than day to day variability in this metric (hence indistinguishable from noise). On the other hand, changes in HRV are larger and therefore more useful (here is a summary of this part of the paper: Recap of our latest paper, part 2). On the other hand, heart rate is a better marker of cardiorespiratory fitness, hence they both serve a purpose, and are not necessarily interchangeable, outside of very strong stressors (sickness, alcohol). In this series I go deeper on the differences, physiologically and in the data, if anyone is interested: Resting Heart Rate and Heart Rate Variability (HRV): What’s the Difference? — Part 1 | by Marco Altini | Medium
Now back to your long-term trends. In the long term, when responding well to training, we want to see a stable or slightly increasing HRV in response to higher load. This is very different from the acute drop (intuitively, training causes damage in the short term but benefits in the long term, both for health and performance). Your data during the first block of increased load is really good, with increased HRV and no suppressions. The second block is less ideal, you have a very good long term trend, but also frequent dips. This might highlight that some sessions were a bit too much (or other stressors were more frequently present). Still nothing to worry about when you bounce back really quickly (in a day).
Allergies and other health-related issues will certainly sink your HRV more than training, so this is one factor to always keep in mind. I often experience something similar myself: https://twitter.com/altini_marco/status/1442419577271504896
To reiterate on the importance of non-training related stressors, below is one of my favorite case studies, one year of data showing a bike accident, a planned stressor (altitude camp), work related stress, and sickness, all highlighting clear changes in resting physiology:
What about your long-term reduction with reduced load?
It is of course difficult to know for sure, but this reminds me of changes with tapering. It has been reported in literature multiple times that during tapering (reduced load), HRV should not really increase but most likely reduce. I cover the literature on these aspects in this blog: Heart rate variability (HRV) during taper | by Marco Altini | Medium
There could be multiple reasons behind this reduction in HRV, as covered in Daniel Plews’ research, for example, reduced plasma volume due to less aerobic stimulus. I would however always think first about non-training related stressors, that we cannot see in the graph, but you might be able to identify as you do have the context (e.g. the allergies, or anything else work or family related, this is just stress after all).
I hope this is informative. Just one more link since you mention potentially going to night readings, and given that you already made it a habit to measure in the morning, it might be good to keep going that way (unless not practical): Thoughts on Heart Rate Variability (HRV) measurement timing: morning or night? | by Marco Altini | Apr, 2022 | Medium
Alright, thank you again for your support and have a nice weekend
Wow, thank you @marco_alt ! I’ve read most of your blogs, but there’s two in here I’ve missed. I will definitely check them out.
I think this week could be related to confounding factors of family stress. This morning, my numbers were back within baseline values for both RHR and HRV, as the stress eased up substantially throughout the week. So it could just be coincident with the recovery this week. I’ll keep an eye on it. I have a no-kidding taper coming up in about four weeks, so it’ll be interesting to see what happens there.
Thank you for your time! I hope the response was informative for others, as well, and not just totally self-serving. 
