A few weeks ago I made a blog post showing one of the ways I use my Heart Rate monitor to track my progress by using the calorie counting function. In the session I filmed I recorded a 1607 calorie burn in 63 minutes. This comes out to 25 and a half calories per minute.
I was informed by many scientifically minded folks that there was no way I could possibly be burning that many calories and that my heart rate monitor was inaccurate, that I was using it in a way that it wasn’t intended. Chiefhiawatha on the Dragondoor forum offered to pay for me to go to get some testing done at Vanderbilt. We wound up talking off the forum and he’s a really sharp guy with a good heart. I matched his payment amount and donated it to the American Cancer Society. Thanks Chief.
So last Friday I went to the Dayani center at Vanderbilt University to measure my VO2 output, calorie burn etc.
First we did the standard vital signs, weight and BF%. More on that in a later blog post.
Next I had my chest hair violated by an electric razor, and they stuck electrodes to me, put a Velcro belt around my waist to contain the wires and then wrapped the whole thing in multiple ace bandages to secure it. The final touch was a mesh tank top that was left over from the 85 football season.
So there I was, all strapped in to the machines looking like a redneck Halloween version of the six million dollar man, without the red track suit.
Then came the mask. It covered my mouth and nose and was strapped to my head tightly enough to create a seal that left my face slightly discolored for several hours. Tubes running out of it to the computer measured gas exchange and other scientifical stuff.
Matt McBryde, RKC 2 was there with me for a little while and took the pictures. He kept chuckling at how ridiculous I looked. Seeing the pictures I understand why. Thanks Matt.
I dialed up my iPod to Twilight of the Thunder God, grabbed my 24kg kettlebell and the swinging began. I switched hands every 10 reps for a little over 13 minutes before setting the kettlebell down at 500 reps. I rested about 30 seconds and went back at it. I stopped counting, but I estimate that I hit somewhere in the 750 range.
I wanted to go for 45 minutes or more but we only had time for 25 minutes in the lab, so we will work with what we got. I was able to see my heart rate and elapsed time on the computer monitor. Three minutes in I hit 160 bpm. I steadily climbed above the 170 mark, never letting it drop below 160 once I got there. The top number was 184. My theoretical maximum based on age is 179. I have hit as high as 189 in training and regularly peg 178-181. After a test or an event, it is easy to look back and wonder if you could have given a little more, but these numbers tell me that I was redlined for most of the test, so I feel pretty good about it.
I was unable to wear my regular HR monitor because of the sensors, but in my training log 2 weeks ago I hit 700 reps in 30 minutes with a 24kg and it resulted in a calorie output of 678. That comes out to 22.6 cals per minute on average.
The machines at Vanderbilt determined and average of 20.7 calories per minute over the 25:00 I was strapped in. So the inaccuracy of my HR monitor is roughly 2 cals per minute, as far as we can tell.
When I talked to Zafer, the guy who did all the testing he told me that my HR monitor was “pretty close” to what was actually going on and that it was good enough for my purposes. If we allow a 10% margin for error above and below both the Met Cart testing and my HR monitor device, there is overlap. That’s what I wanted to know. We talked about the possibility of gearing up for an hour-long foray into the land of the swing. We’ll see what happens.
He also kept saying “you did a lot of work”. I was pushing 298 watts. How loud would I be if I could plug my Les Paul into that?
The thing we both found interesting is that I was able to very quickly (in a about 6 and a half minutes) get to near 100% output and the stay there until the 14 minute mark. I rested about 30 seconds then went at it again. I set the kb down a couple more times during the test, probably less than 2:00 total time spent NOT swinging.
Yes, I did indeed do a lot of work. And I will do more.
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