Battery Muncher (love the name) and mellster; I'll add my own anecdotes on exercise. In school I was one of life's non joiners (another ASD trait?). Didn't like team sports and didn't participate with the result that I wasn't even remotely athletic. I ended up booted out of the rugby team and into cross country which was the last period of the school day. First (and only) time out my only concern was to get back to the gym and showered in time to catch the usual school bus. I ended up beating everyone including those on the cross country team. They asked me to join (which of course I declined - what a drop-out!) and moved on to swimming instead. In my late teens I eventually got interested in sports and fitness and ended up swimming 1.5km every day plus playing squash and Ju Jitsu. Despite undoubtedly being the fittest I've ever been though I did always find it an effort and after a session I was always red faced and took ages to cool down again (temperature regulation being one of the first casualities with a mitochondrial deficit). To cut a long story short I collapsed during Ju Jitsu training and haven't been able to tolerate any aerobic activity since. Despite this I have never become deconditioned. In fact as long as I keep well out of the aerobic zone I can happily shift several tons of firewood with few adverse effects. As I mentioned above I also have little pain while moving but suffer muscle pain and cramps if I sit still or stand still for long. This seems pretty consistent with a switch to Type II muscle fibres as the mito rich Type I fibres are the ones that maintain posture.