There are a number of studies recently saying 6 hours 30 minutes is optimal and sleeping more than 7 hours is detrimental. Some even say 5 is enough. I have to work and study a lot this semester and definitely need extra time. I am thinking about sleeping 5 hours at night, then a 30 minute nap during day, will that be enough, or better not to mess with this? I am not doing weights, and will train 3-4 times per week, which is low for me.