I'm not on insulin @iameshu , but I do exercise everyday with varying degrees of intensity. Talking from a purely exercise point of view, the higher the intensity your exercise the more likely your blood sugars will rise due to your body triggering its 'flight or fight' response. That means your body produces a stress hormone such as adrenaline. Adrenaline stimulates your liver to release glucose, hence the flight or fight mode. Lower intensity exercises do not activate this bodily response so your blood sugars are likely to decrease. That is the simple explanation that explains the contradictory nature of exercise from a purely exercise point of view.