Exercise testing for CFS is like professional boxing: you know you’ll get the crap beaten out of you, but you volunteer for it anyway. The difference is that in boxing, you get paid. In CFS exercise testing, you just hope to get some useful data. I don’t have the results of my testing yet, but I thought it might be helpful to at least share what the experience was like.
The rationale for exercise testing in CFS comes primarily from the research of the Pacific Fatigue Lab at the University of the Pacific. Their research has shown that people with CFS have a unique response to a two-day exercise challenge compared to healthy sedentary controls or people with other illnesses. In the second test, people with CFS demonstrate significant impairment of their metabolic function. In other words, the testing captures the effects of post-exertional malaise. If you want to read more about this, you can check out the series of articles I wrote on post-exertional malaise in 2010.
The Pacific Fatigue Lab testing calls for two cardiopulmonary exercise stress tests (CPET), spaced 24 hours apart (referred to as the Stevens Protocol). I went to Ithaca College to have my testing done by researcher Dr. Betsy Keller, who has provided the CPETs for CFS research by Dr. Maureen Hanson and Dr. David Bell. I was instructed to rest for several days in advance, and to eat frequent carb-rich snacks of fruits, whole grains, etc.
The test began with blood pressure and EKG measurements taken while I was lying down. Then we moved to the stationary bike. I was fitted with a nose clip and scuba-like mask so that my oxygen and carbon dioxide could be measured and analyzed. The EKG leads were hooked up to another machine so that my heart could be monitored throughout the test. Then I sat on the bike without pedaling for three minutes, so that resting data could be collected. My blood pressure was measured every two minutes throughout the test. I got the order to start pedaling, and every two minutes a little more resistance was added to the bike so I had to work harder as the test continued.
And it was hard. Very hard. The techs were constantly shouting encouragement, telling me how much time was left at each resistance level, goading me to push to the next level. Every two minutes, someone would ask me to rate my level of perceived exertion and that was recorded as well. There was so much going on, all I could do was focus on pedaling the bike. The goal of the test is to pedal until you feel you cannot go any further. Not I-would-like-to-stop-now, but I-will-fall-off-the-bike-if-I-have-to-keep-going.
Once I hit that point, they dropped the resistance from the bike and asked me to pedal a little more to start cooling down. I was just on autopilot at that point, barely paying attention to what was going on. They kept taking my blood pressure to be sure that it started dropping back down to normal. Finally, they helped me off the bike and into a chair to recover. The best part was then being helped into the next room to lie down!
On the next day, we did the whole thing over again. It was definitely more difficult the second day, although I don’t have any data yet to say whether they saw the dysfunction they expected. Once I cooled down from the second test, I was helped to the car and allowed to go home.
I think I will do a separate post about recovering from this test. Suffice to say, it sucks. I just hope the test data will be helpful.