Heart Rate Variability (HRV)

Bottom Line Up Front: Heart rate variability (HRV) will let you understand the impact of your training on the health of your system. The more your heart rate varies from beat to beat, the better your system is sitting.  When your heart rate becomes highly regular, it is a sign of stress and a sign you have overstressed yourself.  Measuring HRV will give you an indication when it is OK, debatable, and NOT OK to train.


Gear Needed

  • Bluetooth Heart rate monitor. I bought a Polar H10 because it is by Polar which has proven reliable in the past and because it is bluetooth. Some are ANT+ technology which isn’t bluetooth. You can use this to connect to anything that will allow bluetooth HR monitors. Some Garmin devices, for example, won’t connect to bluetooth HR monitors. This is very annoying. You have to make sure you have a bluetooth one that will connect to your phone to use the app.
  • Smartphone App. I myself use iThlete. See Google Play store.  Also available for iTunes. I find it easy to use. It isn’t cheap, but it’s good.  There are other free apps that will measure HRV using your HR monitor or even some that will measure HRV (your “stress level” is what they call it) using the camera on the phone to check your HR!  iThlete is definitely an upgrade. I tried many free ones before I bought it.

My Experience

I first heard about HRV on a Robb Wolf podcast with his guest Joel Jamieson (listen to it here). It sounded interesting. I read more about it and decided it was worth the investment into a new heart rate monitor and some tech (Android app). Once I got the app, I started logging my results. It is easy to use and lets you record logs over time. It even gives you a color code with each reading that lets you know whether or not you should be training that day based on its assessment of your HRV. Pretty neat. I find it is usually accurate, i.e. days I feel run down or don’t sleep well, my HRV is low and the app tells me to debate it or not to train at all. I always measure it the same time every day (first thing in the morning before any exercise or coffee or food).

I have heard the number of people talking about HRV steadily increase over the past few years. This lends value to it being a valuable metric into your fitness, actually useful, and not a fad.


Only if you are into strength and conditioning, an athlete, or very into physical performance would I look into this. While it would be useful for anyone as a marker of systemic stress, it is unlikely the benefits of this kind of quantification would matter to you unless it would dictate adjustments to your training load.  If you are serious about your performance, this is worth the investment. If you have the cash to spend and are into the science, give it a try no matter who you are.

QUESTION: Have you used HRV before? How do you know when it is time to rest vs time to pump up the intensity? Post thoughts to comments.

References & Further Reading

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