Every body continues in its state of rest or uniform motion in a straight line, except insofar as it doesn't.
I try to squeeze in a workout whenever I can, even if it's doing squats with my 7-month-old in the kitchen or jumping on the trampoline with my 5-year-old.
Electronic aids, particularly domestic computers, will help the inner migration, the opting out of reality. Reality is no longer going to be the stuff out there, but the stuff inside your head. It's going to be commercial and nasty at the same time.