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How to use HRV

I last did a post about HRV, an introduction of sorts, I’ve learned a little more so I thought it was time for another post on the subject. HRV or heart rate variability is a way to tell what shape your body is mentally and physically. It can be used to judge when it’s time to go all out on the next workout and when it’s time for a light stroll. It can be used to measure physical and mental stress as well. Some devices such as Garmin Vivosmart 3 and Lifetrak Zoom HRV are attempting to do all day HRV measurements. How good or accurate (or even useful) these are is very much a TBD. I am skeptical.

HRV is a measure of the variance of time between heart beats. A healthy and well rested system can react quickly to needs of the body. There is good HRV and bad HRV but the reality is there is a range. Too high is bad and an indication of one issue, too low is bad and an indication of another issue. Now I am not a Dr, I am an engineer :). So I will make no attempt to explain the physiology of any of this. What I will try and do is discuss what you can glean from HRV and how to use it.

First up is tools, you will need a highly accurate heart rate monitor. For now that seems to be chest straps. I have a Wahoo TICKR and a Polar H7 both of which seem to do just fine with HRV and give consistent readings. Next up is an app on your phone. The last time around I put a few through their paces and decided on EliteHRV. It is simple to use, easy to understand and works well. If there is anything I wish for, is a portal, where I could see the data offline, on something other than my little phone screen. Oddly enough the app does send the data up to the cloud, I guess for their use.

Taking a measurement is pretty simple, get your chest strap, wet it (most chest straps have to be wet to be accurate), sit still start the app and wait two minutes. Two minutes seems to be about the right amount of time to get a reliable accurate consistent HRV reading. The more still you are the better the measurement. For the first couple of days you will get nothing out of the app while it figures out your baseline, normal, state. Once done you are now ready to start getting some meaningful data out of the app.

I am not going to try and discuss HRV during an activity, at this point I have not figured out what it means, or even how accurate or useful it might be,

So let’s get started. After taking measurements for a bit it was time to see what shape I was in before a ride. So I took the measurement, and as you can see I am in the green and good to go! The intra chart shows a pretty stable reading.

The reading isn’t right in the middle of perfection but it’s well within the range of what it considers good for me. So off I go on a ride. I rode for 2.5 hours, and then retook my measurement. Sure enough it shows that my body has been under some considerable exertion for me). My HRV had dropped from 59 in the morning to 36 after the ride. The only thing missing would have been a nice simple dial again. I have no idea why they only do this for morning readings.

So the next morning I measure my HRV again. Here you see I have recovered from 36 back up to 51, but it’s still in the yellow meaning if I were to go out an hard exercise it might be a bad idea. I would be at risk of performing badly or even injuring myself pulling muscles and the like.

By the next day you can see my HRV had recovered back up to 58 (now two mornings, and roughly 36 hours after my ride). As an interesting note, my Garmin Fenix 3 gives you a guess at what it thinks is your time to recover from your workout, and it guessed 29 hours so in the same range.

Now to see the affect of things other than exercise, I had a really bad night of sleep. And low and behold my HRV, down to 51, reflected it and showed a deccrease and the fact that I would not be in a good place to do a hard workout, something I felt anyway.

Here’s another pre exercise HRV, then a post exercise and then the next morning. This time it dropped from 54 to 43. This was an easier ride 688 calories Vs 1244 (according to my Fenix 3) from the previous example and as you can see my HRV dropped only 11 this time Vs 23. And as you can see it took less time to recover from my exercise, the next morning I would have been good to go again for another workout (albeit just barely).

And for completeness here is an almost perfect HRV after a good long nights rest. Right smack in the middle of the good range!

This last image is a way of seeing it all in one. You can see here it’s about a range. Too high is bad, too low is bad. It’s about distance from center of your normal. You get the best readings and accuracy when you take your HRV regularly.

May 19, 2017 Posted by | Uncategorized | Leave a comment