Too little is not real beneficial either. It appears that some activity helps to relax the student and still leave time to focus in a concentrate the remaining time to quality studying. Health Take care of yourself. Your brain will not function properly if you abuse it. Alcohol, drugs, tobacco will all have a negative affects on your performance.
Proper diet is also important.
As is a good night sleep. So at the risk of sounding mother hennish take care of yourself so that you can make the most out of your college experience. If you do get sick or have to miss a class try and get someone to tape the lecture for you. That way not only can you get someone's notes, but you can hear the lecture yourself. Take advantage of the college culture.