xiv MUSCLES AND EXERCISE 199 



138. Value of Exercise. Next in importance to the 

 quality and quantity of foods and air for keeping the 

 muscles in a healthy condition, is the matter of exercise. 

 The blacksmith has a large, strong right arm because 

 he uses it so much. The muscles of the athlete grow 

 strong because of constant exercise. A muscle that is 

 not used becomes soft, flabby, and feeble. 



Regular daily exercise of the muscles increases the 

 action of the heart and lungs. More blood containing 

 food and oxygen is pumped to all the organs of the 

 body. The muscles used most reap the greatest 

 benefit. Proper exercise is beneficial to both old 

 and young. The young, growing person requires a 

 greater amount of exercise than the adult. As long 

 as a muscle is growing, exercise will tend to make it 

 grow larger and to develop it better. That is why 

 those who get a great deal of outdoor exercise look 

 healthier and are better developed physically than 

 those who live indoors most of the time. Exercise 

 and sunshine make people well and strong. 



Muscular exercise has a wholesome influence upon 

 all the organs of the body. The digestive apparatus 

 grows stronger; therefore more foods are eaten and 

 they are better digested. The heart and lungs grow 

 stronger and are able to do their work better. The 

 lymphatics perform their functions of draining the 

 wastes from the cells with greater efficiency. The 

 skin, liver, and kidneys remove the waste materials 

 from the blood more easily. The brain gets a larger 

 amount of nourishment and the mind is clearer and 



