The best way to help all this effort of Nature to give you a nervous system which will stay by you when the worries and trials of life come, is never to over-exercise at any time, and not to exercise at all for a few days before and a few days after your periods. This is the time when your body needs all the reserve power for one purpose. How can I tell when I need rest instead of exercise? The best sign is when you think that you ought to exercise but don’t feel like making the effort. Many, many a girl has become a nervous wreck because someone forced her to exercise when she needed to be quiet and at rest. Never exercise unless the anticipation of the play or game is a pleasure to you. When you get into that state of mind such as, “Oh, I don’t feel like making the effort; I’d rather sit here and read, or talk”――if you feel like that, if you have to make up your mind that you must exercise, but it is difficult to find any pleasure in the thing you are thinking of doing; don’t try to do it. If you make determined efforts to do any physical work that is distasteful to you, if you work by the clock, then you are injuring yourself every minute you are at it. You are drawing upon your nervous capital, not upon the interest. This is the secret of all exercise, brain or muscle: work must be done upon saved-up interest, not upon the capital. If you use the capital, it only means for the body what it would mean for the purse――bankruptcy――sure and certain failure. Any physical effort which leaves you feeling worse than when you started, is injuring you. This does not mean a good physically tired feeling, one in which your cheeks are aglow, when you feel elated at what you have done, when a cold shower bath feels good instead of making you shiver and covered with “gooseflesh,” but that feeling of complete exhaustion, pale cheeks, a feeling of shivering if cold baths are mentioned and a longing for something to drink that will brace you up. When this latter state is yours, you have over-exercised or else exercised at a time when your nervous motor needed a rest, not disturbance. You sometimes hear it said, “Why, she is the last girl in the world I thought would ever get nervous troubles. She is the best girl on the team――Oh! you ought to see her muscles.” Yes, but you should also see those worn-out nerve cells. Misdirected ambition, a forgetfulness that she had only a certain amount of nervous power, an excitement which blinded her to her real condition; these were the factors which made her drive her motor far beyond its powers. Finally there was no more nervous energy to move her over-developed muscles without fatigue, and fatigue has its own poisons which penetrate the whole body and then comes a collapse. This was the cause for this “strong girl’s” nervous breakdown.