In the early days of HRV, I measured my beat-to-beat measurements using my iPhone (occasionally paired to a Polar heart rate monitor) to gauge my training load. But it was an inconsistent predictor because I needed to make sure to take the reading every morning under the same conditions, etc. Given the challenges that surround our household’s morning routine, that kind of manual, tedious process for gathering HRV data never really let me get confident baseline data.
Now, the Apple Watch collects HRV data and — given how difficult it was to do it manually and get good baseline data — I was skeptical that the Apple Watch would be able to use sampling my HRV throughout the day to generate anything useful. I’m still skeptical, but my recent/current bout with Lyme disease over this past week has given me more confidence in the Apple Watch’s sampling technique to set a good baseline and show variance from that baseline.
I think this picture is pretty self-explanatory but will add that when my HRV fell to its lowest around 11/12, I could barely get out of bed, was sweating uncontrollably and could not stop shivering. By the 15th, after 36hours of doxycycline, I felt about 80% better. I am still not 100% despite a rebound in HRV.
So, HRV on the Apple Watch is good at showing when you’re REALLY sick. That seems to be all I can take away from it at this point, but at least it shows that the Watch’s sampling approach does reflect reality, even if it doesn’t yet predict or give early warning.
I’ve been tracking my own HRV for many years using a stand alone device called the EmWave. Now though with the advent of bluetooth heart rate monitors and iPhone apps, you can get a whole lot more info pretty easily.
Here’s the deal though: you need to use a really high-quality bluetooth heart rate monitor to get decent data. I had been using a cheap Jarv heart rate monitor for years to track my heart rate while running, riding, doing intervals, etc. And it works just fine for that stuff (if a bit flakey at times and does seem to run the battery out pretty quickly, but, you gets whats you pays for).
I paired up my Jarv with an HRV app on my iPhone though and it reported my variability as wicked low. At first I was concerned that maybe I didn’t have high HRV I thought I had. Then I tried the HRV app with the much more expensive Polar H7 and my HRV #s were way up there.
It appears that the way the Jarv reports the intervals between beats (R-R) is not quite reliable when compared to the way the Polar does the same reporting. I only found one other link on the inter webs that noted the Jarv under-reported HRV and since not everyone may have multiple monitors around to test with, I just wanted to note here that if you start tracking HRV and want reliable data, don’t use the Jarv heart rate monitor. Spring for the Polar one.
* by way of example of just how fascinating the rabbit hole is here: Low HRV correlates with depression but while antidepressants (specifically SSRIs) may alleviate the symptoms of depression, they do not increase HRV. It would be interesting to see a study on whether or not Cognitive Behavioral Therapy (CBT) – which is shown to be as effective as medication in long-term alleviation of depression – causes an increase in HRV.