A bout of exercise is about the last thing you'd imagine a person with chronic fatigue syndrome – also known as myalgic encephalomyelitis and often designated by the acronym ME/CFS – would want to endure. And you'd probably be right.
But a new study suggests that a blood test following exercise may be a very good way to differentiate between people who have ME/CFS and people who don't. That's important, because one of the things that have made efforts to treat and, perhaps, cure the debilitating disorder – which according to Stanford ME/CFS expert Jose Montoya, MD, afflicts between 1 million and 4 million people in the United States alone – almost preternaturally difficult has been the difficulty in establishing a definitive diagnosis for it. (That explains the large range in Montoya's estimate of the number of people with ME/CFS: A lot of people who have it don't know they have it – or at least their doctors don't.)
Recent work by Montoya and other Stanford researchers has identified a "signature" consisting of altered levels of as many as 17 different bloodborne substances in ME/CFS patients. But the signature is written in disappearing ink: Patients with an ME/CFS status of longer than three years in duration appear to lose it. Likewise, levels of some of these substances move in opposite directions among patients whose cases are more severe versus patients with less-severe cases.
All of which says something about the pitfalls of statistics. As I wrote in a previous blog, "the 'average' human has one breast and one testicle." Simply combining the results for new and old ME/CFS patients, or more versus less severe cases, with respect to these measures would have wiped out all traces of the signature.
The new study, conducted by Montoya, cardiologists Francois Haddad, MD; and Kegan Moneghetti and several other Stanford scientists, showed that a round of rigorous exercise heightened the differences in a set of cytokines (blood-borne immune-signaling substances) that could effectively distinguish sedentary people without ME/CFS from a selected group of ME/CFS patients with significant post-exertion malaise but who were still able to get through the exercise regimen safely.
The work appears in Scientific Reports.
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