But which is the cause? Perhaps someone convinced they're ill, weakens their own immune system - either through some psychosomatic mechanism, or through associated behaviors.
The disease is very poorly understood but one common symptom seems to be a low tolerance for excercise. CFS patients recover very poorly from exercise, and a day of even moderately increased physical ativity may cause them to "crash" and become debilitated for multiple days.
It is also worth mentioning that CFS patients often have normal results for cholesterol, blood pressure and so on. One reason why biomarker studies like this one are important is exactly because currently CFS patients often end up bouncing from doctor to doctor, and none of the diagnosis ever work.
Please don't idly suggest that CFS is just something psychosomatic or behavioral. The disease is much more debilitating than that, and this very common psychological misdiagnosis most often leads to dangerous advice. For example, CFS patients are often told by doctors to excercise, which actually only makes the symptoms even worse.
Sarah Myhill is a crank who sells blood tests and weird megavitamin mixes to vulnerable people.