"This is misleading. ME/CFS is not the outcome of poor lifestyle choices. It's a severe, complex disorder of the nervous and immune systems. A tiny percentage of victims, nearly all of them young, may recover their former vigor as Stu did (if indeed he had ME/CFS—it is not widely understood and misdiagnosis is common). For most victims, strenuous exercise of any kind causes pain to spike and savages the little strength they have, possibly irrevocably. "