I do the odd morning run (before work 6am) 2-3 times a week as well as my after work runs. i do em on an empty stomach i only do 3-4 mile at easy pace on the fells just to help up the milage with a faster pace in the afternoon, tried upping the pace once and thought i was gona have a heart attack think its to much to push it after just waking up! so morning runs are just to loosen the legs off and get a few extra miles in for me, its also nice to be on the fells 1st thing.