Well, I used to exercise in the mornings only because I wanted to spend all day at home on the computer or watching movies "honestly I had the whole morning free so I used that time training" now I sleep all morning and exercise in the afternoons, I find it better "I need to rest a lot because I end up very tired from training" so I exercise at 3 in the afternoon and I finish at 4:30 or 5 in the afternoon, then I spend it on the computer. I certainly feel that now I'm not on my computer too much and I'm giving my eyesight a good rest. But I really feel and think that there is no perfect or mandatory time to exercise, I exercise just to stay in shape.