What effect does sleep have on exercise?

BIG. Important to sleep enough (usually 8 hours, continuous) to allow for healing and resting of the muscles, among other things. Sleep is not overrated ---- it is critical to good health and will affect your exercise abilities/performance, as welll as recovery and long-term achievements. Sleep well, and long !
Helps. I get asked often if exercise helps sleep, is that the question you meant? I think it helps both ways: healthy sleep provides good energy to work out and conversely, exercise can promote restful sleep. I would not try to exercise too late or just before going to sleep, your body needs some time to unwind and relax...
Sleep is important. Sleep affects almost every aspect of total fitness. Sleep loss reduces physical performance primarily by reducing the motivation to engage in physical exercise as the effects of sleep loss on strength and endurance are relatively minimal.