I agree absolutely with former President Kennedy that physical fitness is very important for a healthy body. Being healthy and strong is very important when it comes to doing your best. When you are at your best physically it wells good, you feel more energised and inspired, and that leads to even greater things. Doing your best intellectually is very dependent on how good you feel. If you for not sleep and take care of your body you will not have enough energy to do simple things in life. Going without sleep affects your entire day. Mental health is  also very important as well. If you do not feed yourself properly you might  feel lazy and tired, which will not help you get to the peak of your intelligence and skill.  There is no way to do your best if you do not put the effort in becoming your best. Having a healthy body is extremely important to being the best you can be, all you have to do is take care of yourself.