One of the main issues with Chronic Fatigue Syndrome is the postexertional malaise we experience. To some people, we appear healthy because they see us participating in an activity or at work and they think we are okay. Usually what happens and what other people don’t see is the consequences of that activity later that day or the following days or weeks.
Many investigators have used exercise testing to identify markers of fatigue. I actually had the exercise testing done that I will be talking about in this article over two years ago. It it sort of like a stress test, except you are riding a stationary bike, and wearing a mask at the same time. This test determines how much oxygen is consumed (VO2) for volume of oxygen consumed. Your heart rate and blood pressure are monitored and tracked throughout the entire test.
An important part of this test for CFS patients is you need to get to the maximum target heart rates and exercise level and you can’t quit if you get tired. You do have to push yourself, but as I was told, it is necessary in order for the testing to be accurate and to prove if you are or are not disabled.
According to the article by the CFIDS Association, Science & Legal News on Postexertional Malaise:
“To survive and to carry out activity, the body must extract oxygen fromnthe atmosphere and transport it to every cell in the body, where it’s used for essential metabolic processes. Oxygen and energy are inexorably linked.”
The research team found and noted in their paper that reduced capacity is evident with using the test-retest approach. During the study, six CFS patients and six sedentary, but otherwise health people were put through the exercise test on two consecutive days.
The first exercise test on the first day showed no difference between the CFS patients and the healthy people. After the second exercise test a day later, the CFS patients showed a significant decreased oxygen consumption when compared to the mean of their first test and compared to the VO2 of the healthy people in the second test. This is what the authors of the study (J. Mark VanNess, PhD, Christopher Snell, PhD, & Staci Stevens) had to say:
“The fall in oxygen consumption among the CFS patients on the second test suggests metabolic dysfunction rather than sedentary lifestyle as the cause of diminished exercise capacity in CFS.”
Implications for CFS disability claims
The exercise stress test is one of several tools used by the SSA to determine disability. For CFS disability and other conditions, the SSA requires that there be proof of the existence of a “medically determinable impairment” and the inability to do any kind of work. The SSA considers an abnormal exercise test an objective medical impairment in CFS.
The researchers on this study though want those with CFS to realize that just a single exercise test will probably not offer up the proof necessary that the SSA requires for disability. For me it did, but everyone is different. The single exercise test does not show a difference in oxygen consumption between people with CFS and those who are healthy in most cases.
The authors said that:
“The initial data from this study suggests that the test-retest format offers a superior basis to establish disability consistent with SSA policy and other relevant case law.”