Once you get your body in shape, you can’t stop working out. Within a short time your muscles start losing tone, and where you once could do fifty sit-ups, twenty is now your maximum. You must keep at it. The intellect acts in the same way. When problem solving, stimulating discussion or reading is a part of your daily life, your mind is sharp. After a two-week vacation of lounging on the beach, your brain feels soggy.
