Thanks Cort - interesting Qs and As.
I was puzzled by his statement that when people are better enough to exercise in the way they did before they were ill, they're 100% recovered, and won't get ill again.
Not the case with me, and some others I know. After being ill for 8 years, I was welll for many years and was ski-ing, playing sport, hiking etc. But then started to get relapses, and have been ill again since 2002. Other researchers have found that the illness often recurs after a long period of remission.