I just watched this online last night & was wondering if anyone here had tried it.? He stated a study was done where they had ME/CFS patients walk on a treadmill for 3 minutes then rest for 3. In all 10 repetitions of this. He said no-one had PEM or crashed. He also suggested wearing a pedometer & doing between 1000 - 5000 steps per day, no more/no less. Sorry, I don't have the link but it was called the Stepwise Approach, May 2010.