I read something a few months ago - cannot remember the source or I'd quote it - that said first thing in the morning your arteries/veins are so dilated that they're virtually identical to that of a SMOKER. YIKES!! So call me crazy but I'm thinking morning is NOT the best time to be exercising. The article went on to mention that the vein / artery constriction that occurs naturally overnight is at least partly to blame for the high incidence of early morning heart attacks. Interesting...