“This is cool,” I keep saying to myself. “This is really cool.”
It’s Friday morning, and I’ve skipped work to be here, standing half-naked amidst hundreds of thousands of dollars’ worth of medical test equipment, with electrodes affixed to my chest, a blood pressure cuff on my arm, on oxygen sensor on my finger, and an industrial grade treadmill standing a few feet away that is capable of humming along at 4:00-mile pace and tilting the belt to a grade that would make a mountain goat faint. Nearby are multiple computer screens showing my heart rhythm and other vitals. I’m about to star in every runner’s dream role as experimental subject in an honest-to-god V02 Max test.
It is, indeed, very cool, but I’m also nervous as hell.
The truth is, I’m not having this test to prove or disprove the effectiveness of some training program or other, and I’m not here because anyone really cares what my maximal aerobic capacity is. As my cardiologist said when she was setting up the appointment, she wasn’t ordering a V02 Max test so that I could go home and brag about it to my friends. Ouch. That was exactly what I was planning to do.
No, the main reason I’m about to step on this treadmill is because we’re trying to solve a little mystery about the way my body responds to the early stages of exercise. Maybe — if we’re lucky — the test will reveal something interesting about my cardiovascular or pulmonary systems. I suppose that’s the main source of my nervousness. On the one hand, it would be great to “fail” at the test, which would mean replicating the negative experiences in recent races while obtaining hard evidence about how my body is responding to exercise stress. On the other hand, “failing” means reaching exhaustion prematurely, and it’s physically unpleasant, not to mention that I’ve never had it happen on a moving treadmill.
The lab assistant who is administering the test is matter-of-fact as she explains the protocol, including how to signal when I reach the point where I think I can’t continue. After taking a set of resting measurements, I’ll start running, with the belt set to move at a constant 6 miles per hour (10-minute miles). I’ll have ten minutes to warm up with the belt set at a gentle 1% grade. After those initial ten minutes, the grade will be increased by 0.5% every 15 seconds, while the pace remains constant:
0:00-10:00 - 1.0% grade 10:00-10:15 - 1.5% grade 10:15-10:30 - 2.0% grade 10:30-10:45 - 2.5% grade 10:45-11:00 - 3.0% grade 11:00-11:15 - 3.5% grade 11:15-11:30 - 4.0% grade ...
In addition to the leads connecting my chest to the machines measuring my heart rhythm, I will also be wearing a mask with tubes attached so that all the gasses I inhale and exhale will be measured for oxygen and C02 content. When the mask is on, it increases the feelings of claustrophobia, but otherwise it’s not uncomfortable. When all is in place, and I’m completely connected, I signal that I’m ready to go.
When the test starts and the belt begins moving, I’m taken aback by how fast 10:00 miles feel at first, but after a brief panic, I’ve settled in, and after a minute or so I’m beginning to get comfortable. In fact, I start feeling so much better as my body warms up. The gentle pace begins to feel like a jog and I can feel myself relaxing. Sitting immobile with no shirt in the cool lab, I had felt chilled, but now I’m starting to feel warmed up and I’m actually starting to enjoy myself.
Soon enough, the initial ten minutes is up, and the grade is increased. No problems, at first. In fact, for the first couple of minutes after those first ten, it feels easier, not harder, to be running on a slightly more challenging grade. But now I begin to realize that 15 seconds is a very short amount of time, and as soon as I’ve adjusted my stride to the new grade, it’s increased again. After 4-5 minutes, I’m starting to perspire, and I’m really having to focus on my running form and on staying properly aligned. I think I might be wobbling a little bit, because the lab assistant says at one point that I should try to stay in the center of the treadmill. Meanwhile, every couple of minutes, she is taking my blood pressure, which requires me to hold my arm out straight for a few seconds. What had been an inconsequential break in concentration has become a major logistical issue.
And still the grade increases, every fifteen seconds, without fail.
At around 15-16 minutes in (12-13%), I’m touched that the lab assistant who has been absolutely business-like up until now, begins to offer encouragement. “Good job,” Great work,” “Keep going…” Later, I think this is probably all part of the protocol. The whole point is that I run to the point where my body can’t make use of any additional oxygen, so if I give up too soon, then the results aren’t quite as clear.
Now I’m dreading the sound the treadmill makes when the grade is increased by another half a percent. But at the same time, I find it easy to focus for those fifteen seconds. “I can do this for another fifteen seconds,” and then it gets steeper, and I try to reset my expectations and say “I can do THIS for another fifteen seconds.”
Towards the end, at somewhere between 17:30 and 18:00 (sorry, I can’t remember when it was exactly — I was preoccupied with trying not to fall off the treadmill), I start being anxious about being able to grab the bars that signal that I’m done. I don’t feel like I’m quite at exhaustion, but I’m definitely at a point where I’m feeling impaired to the point where my coordination is failing. And at that point, I make the decision and lunge for the bars. Immediately the lab assistant hits a button and the treadmill slows and the grade lessens. In a few minutes, I’m walking on near-level “ground” and immediately feeling twinges of regret that I didn’t actually give it my absolute best.
A little later, going over the results with my cardiologist, I feel a little better seeing that in the final 30 seconds, my heart rate and my oxygen consumption did, in fact, plateau. I was running harder, but the energy was most likely coming form non-aerobic pathways. I might not have run to total exhaustion, but I did run to maximal aerobic exertion.
And the results?
Well, they were pretty normal results for a well-trained athlete. My V02 Max was measured at ~166% of normal for my age, which was to be expected given my running background. My max heart rate was a bit lower than predicted for my age. More importantly, at least in this test my body responded appropriately to the exercise stress, so there was no clear indication of any specific issue. But given my prior symptoms, my cardiologist deemed the test “equivocal,” neither proving nor disproving the hypotheses we had going into the test. In other words, more tests are needed. Again, not a surprise.
Other than that lingering regret at not having given my absolute best (when I shared that feeling with the cardiologist, she kind of laughed and said she heard that a lot from runners), I was satisfied with the test and happy that I had “passed” it. As I’ve written in a different post, it was a strange way to prepare for a race two days later, but it gave me peace of mind about many things, and made racing easier, even if my calves were a bit traumatized by struggling with that steep grade.
(To be continued… eventually… )
Interesting Jon. My experience with the stress test I took 10.19.15 turned into an emergency! Feeling lousy in mid September my PCP ordered one for me as a precaution. In retrospect she messed up not recognizing the obvious symptoms but that’s another story. In any case I failed big time. Six hours later the cardiologist, now my cardiologist said I was a very lucky man. Turned out to be one very blocked artery which they fixed with a stent. So now I’m on a statin (the horror) and back to “normal” with no damage to the heart muscle and all other arteries in good shape. I tell my story in much more detail a lot not to engender sympathy but you just never know what the heck is around the next corner!