Run to Win With Self-Control

You would fain be victor at the Olympic Games, you
say. Yes, but weigh the conditions, weigh the consequences; then and then only, lay to your hand—if it be for your profit. You must live by rule, submit to diet, abstain from dainty meats, exercise your body perforce at stated hours, in heat or in cold; drink no cold water, nor, it may be, wine. In a word, you must surrender yourself wholly to your trainer, as though to a physician.
— Epictetus