............ and what I still can't get my head around is why is it that so few flight-crew seem to be afflicted with it, inspite of spending a veritable lifetime sitting immobile on our arses ! .... and certainly so when compared to the few short hours your average pax is exposed to this (apparent) risk, i.e. surely if the title of the thread is true then surely 1 in 10 pilots should be similarly effected ?