Exercise also helps lower
blood sugar. Muscles need
glucose in order to function, and the two things which deliver that
glucose are insulin and adrenaline, and adrenaline is released during exercise.
As for sleeping late, that shouldn't have any direct effect on blood sugars. Getting a good night's sleep can make you feel better overall, though, and that positive influence can improve your mood, which can actually lower you blood sugars after you wake up.