It's hard for healthy people to imagine what this is like...I spent about 2 years almost 100% bedbound and it is hell. Showered about once every 10 days because that's all that my energy budget allowed.
Some people in this severely ill state experience partial spontaneous recovery but some certainly do not.
Headline: Former Olympic sprinter in bed 22 hours a day with ME/CFS.
https://athleticsweekly.com/news/beth-dobbin-i-feel-like-ive-lost-everything-1040013690/