Anyone using HRV? (Heart Rate Variability)



I just put the HR strap on for a couple of minutes in the morning to take the reading. My wife already thinks I’m strange for riding my bike in the shed, without me wearing a HR strap to bed as well :grin:

I’ve never used any sleep tracking apps. The Polar H10 has got Bluetooth connectivity though, so I assume would work with most apps.


I do the same with a hr strap and HRV4Training in the morning. It seems easier to me than using my camera.

It’s worth noting that not every hr sensor can provide that information to the app.


I use Biostrap when sleeping. It measures multiple things such as Sleep, O2 saturtion, etc. So far I like it. #Notsponsored.


I used the “Sleeptracker” app for iphone for awhile. You put the phone nearby on the bed, and it uses motion sensors to detect your duration and quality of sleep. It gives you a “score” based on sleep efficiency (whatever that means) and duration relative to your goal sleep amount.

You can also set it up to record any snoring or apnea events, which it did reasonably well. It has an alarm function that times the wakeup within a user-selectable window, presumably to wake you at the right time of your sleep cycle, if possible without going over the set wake-up time. My only complaint is that if you snooze the alarm and go back to sleep, it doesn’t include this in your sleep duration.


Mostly I’d be interested in an app that tells me “you are asleep.” As far as I know, sleep tracking apps are notoriously bad at actually determining different sleep stages so I’m skeptical about the alarm functions.


That’s really all I use mine for, I only give passing glance to my “sleep stages” it’s mostly just to see how long I sleep. I also use the sound recording to tell if I’m snoring excessively, I use pillow by the way.

I’ve been using HRV4Training for a month or so now, and I am pretty impressed with its ability to discern how I feel. Pretty much if it says I’m sucking, it’s right. More to follow on this one I’m sure.


I will add one more for “thumbs up” HRV4T. I think I’ve been using it for almost since it first came out. Well… at any rate for at least the past 1.5 years or more.

Is it useful? I am no bio-scientist, but… I do like having another data point to add to my training and to aid in my body’s need for recovery days. At just a couple weeks south of turning 60… I find this useful. On those days I am just dragging or feeling ‘off’, my HRV is often below normal values. Personally, knowing this gives me the ‘permission’ to take it easy that day or even, just take the day off the bike and do errands or chores or just vegetate with the family.

I also like the convenience of using the phone camera and light for the measurement. Because I sleep with the iPhone next to my bed, I can wake up and immediately take my morning HR and HRV reading with minimal movement or disruption that would otherwise increase my HR. Something I believe putting on a HR strap would do.

Using the app, you can also see how you compare against others in your age group or gender. This is just a fun fact to know.

Finally, you know that nothing is free. The ‘app economy’ exists because the developer is is gathering and profiting from the information gleaned from your data or “user content” even if they say they aren’t (reference the recent news about Facebook’s dealings with personal data). If I am going to give away data, I don’t mind it being used for research to benefit other athletes.

Now… if my HRV4T data stream could only be exported to my TrainerRoad calendar… I could consider dropping my paid subscription to a different app I also maintain and track my training data… :thinking:

– Jeff


From what I understand HRV isn’t about heart rate, it’s about the variation between the beats. So, in my mind at least, it shouldn’t matter if you get up and put on a HRM strap as you’ll then be minimizing movement during the measurement time.
But I can see how it’s a concern if you’re interested in resting heart rate. Like you I also use the hrv app when my alarm goes off since I’m still in bed.


Yep. That is also my understanding… HRV is variability in the beating of the heart. Is it steady or syncopated and by how much? (A great explanation is here:

I’ve used my morning HR as an indicator of my fitness and need for recovery since HRM’s for athletes appeared in the 80’s. I know that when I wake up with an elevated HR, for me… HR=56+ (normal now ~ 48-52 bpm), I know I am dehydrated (need to drink more water during the day) or… perhaps drink less… alcohol the evening before. :yum:… or maybe I am coming down with a cold or other illness.

It is not everything, I use it as just another indicator/gauge to use in monitoring the impacts of my training program.


HRV is highly correlated with HR (inversely) - so if you measure HRV lying down after waking when your HR is 50, you’ll get a different measure vs if you stand up and your HR goes to 60.

Main thing when using HRV is to take the measurement in the same way/time of day each time you measure.


I’ve used hrv4training for a while now and I’m not sure what to think of it, personally. I’m a 44-year-old cyclist who has always ridden bikes but in the last decade, I’ve started racing and running very regularly. I almost NEVER see an indication that I should limit my intensity even when I know that I need a break. Even after the most challenging TR workouts (oftentimes failed workouts) or high mileage days in the saddle, I just don’t see much variation. I have used it on various phones with the optical sensor (and a strap for a short period of time), same time every day (lying down, first thing in the am). I always get a clear reading and never have to retest (ECG looks great).

I know for a fact that I cannot take the highest levels of TSS without risking poor mood/illness/injury/etc, but this application never tells me to back off. Am I just not their target user? Anyone else seeing the same results from this application all the time, regardless of training stress?




Ive noticed of late that I don’t usually get “lay off” alert the day after a hard workout, but rather the second day after. Its probably accurate, because I’m usually more sore and feel a little more iffy those days.

I try to treat it like anything else, its a tool. Maybe more will come of it eventually, probably when I understand it better. Marco is a very smart fellow, and they have posted a TON of supporting information on their site. He posted a blog entry for the end of the year called “The Big Picture” where he kind of puts in context, you might want to read that. I know I’m a geek for the stuff, but I found it informative.


Its funny you mention the arrhythmia issues. I live in Florida and consequently sweat like its my job in the summer. Another friend, who is about 15-years older than me, started having some mild cardiac issues. Multiple Dr’s advised him to start using Magnesium supplements to help. Their explanation was that in intense heat, endurance athletes have super high sweat rates and typically have low levels of magnesium- which is difficult to test for by CBC. Just a thought- or something to explore.

In regards to the Apple Watch- I got a 4 a few months ago. The HRM in the watch is surprisingly very accurate and has a HRV feature through the Health app.


Absolutely. The serum magnesium level (what you get from a normal magnesium level blood test) can be normal and the total body magnesium can be low.
Actually I take magnesium daily…it helped amazingly well with my PVC’s (premature ventricular contractions).


I think HRV is a very valuable indicator. However, taking a snapshot in the morning is absolutely unreliable. I am using Emfit QS and it measures HRV throughout the night. There is a very high variance over the night and even in the morning hours. Measuring 5 minutes earlier or later might lead to completely different values. Take a look at a nightly chart.


So how do you make use of day to day changes in a metric that bounces around from hour to hour anyway?


So, my experience in using HRV for around a month:

  • it correlates with well with my general perception of fatigue (i.e., upon waking if I feel poor, my HRC tends to be suppressed);
  • I have a solid idea of my HRV baseline and use morning HRV to guide training. So far, I’ve not had to abandon any sessions;
  • HRV tends to reflect previous day’s activity - SS = no decrease in HRV next day, VO2 max = perhaps 2 day decrease, returning to normal on the 3rd day, and Threshold stuff = single day decreased value.
  • I have tracked it consistently every hour over 1) a training day and 2) a non-training day to see hourly fluctuation. Training days showed logical decrease after a session, whereas non-training day it remained relatively constant.

To put into context, my baseline HRV value is 70, HRV CV is usually around 5, FTP = 330, and I’m 37y.o. with around 8 years of training and racing.


The nighty average value and trend remains very helpful. A rested body shows higher averages than a stressed body.
Normally you see a lower HRV value in the evening and a higher HRV value in the morning - resulting from nighty recover. This is not always the case though and sometimes misleading. Emfit therefore also shows a 2nd indicator “Integrated Recovery”:

Integrated Recovery is the area remaining under the RMSSD graph, and in some sense it indicates how much recovery you gain during the whole night. For example, some people may start to recover very nicely (RMSSD graph shooting upwards) during early hours of the night, after they go to bed and fall asleep, but towards the morning hours they may start become anxious (for example because of work stress), and their RMSSD starts to decline. As a result, morning RMSSD may be quite low when compared to evening RMSSD, thus indicating poor recovery, even though during the night there has been some good recovery. This is where integrated recovery steps in, as it indicates also this good recovery earlier in the night.
Integrated Recovery and Total Recovery should be checked together; even if Total Recovery is low, but Integrated Recovery is medium or high with regard to ones own history, then there has been some recovery. On the other hand, if they both are low, then recovery is propably not sufficient, and one should avoid stressing him/herself too much, for example, avoid very heavy physical exercise.

Total Recovery as difference between morning and evening HRV values:
Recovery is simply difference between morning and evening RMSSD values. Usually it should be positive, indicating that there has been efficient recovery and resting during the night. Of course, this should be analyzed with regard to activities of previous day: if previous day was very light (no stress, no heavy exercise) and evening RMSSD is relatively high, it is not reasonable to expect high Recovery number, because there is no load to recover from.

Values of Recovery are highly individual, and you should inspect them against your own baseline values, and also in comparison to Evening RMSSD values.

Emfit takes an average of an unknown period in the evening and morning to define the Evening HRV values and Morning HRV values. In my posted chart you the evening value to be well above 30 while the first reading is just above 20.



Using Garmin HRV 24/7, I can clearly see that average HRV keeps lowering during an intense training period, like the TR mid volume plans. When sick, stressed or tired from lack of sleep, the same thing happens. During the planned rest weeks in TR plans, my HRV goes back to my normal levels.

I wouldn’t even try to use HRV from one moment during the day for anything. Average over the entire night/day is the only useful measurement for me.