Is 6 hours enough sleep a night? I want to try waking up to do cardio in the morning, then doing my lifting or training in the afternoon/evening... but I would have to wake up at 5:30a to get my cardio in, only giving me about 6 hours of sleep a night. Currently I'm lifting 2 days a week and training MMA 3 or sometimes 4 days a week. I don't have time to spend on just cardio as much as I would like. I really want to drop weight but I also need a strong cardio base if I ever want to compete.