Exercise is as much of a vital necessity for man as air, water and food, in the sense that no man who does not take exercise regularly, can be perfectly healthy. By “exercise” we do not mean merely walking, or games like hockey, football, and cricket; we include under the term all physical and mental activity. Exercise, even as food, is as essential to the mind as to the body. The mind is much weakened by want of exercise as the body, and a feeble mind is, indeed, a form of disease. An athlete, for instance, who is an expert in wrestling, cannot be regarded as a really healthy man, unless his mind is equally efficient. As already explained, “a sound mind in a sound body” alone constitutes true health. Which, then, are those exercises which keep the body and the mind equally efficient? Indeed, Nature has so arranged it that we can be engaged [Pg 60] in physical as well as mental work at the same time. The vast majority of men on earth live by field-labour. The farmer has to do strenuous bodily exercise at any cost, for he has to work for 8 or 10 hours, or sometimes even more, in order to earn his bread and clothing. And efficient labour is impossible unless the mind is also in good condition. He has to attend to all the many details of cultivation; he must have a good knowledge of soils and seasons, and perhaps also of the movements of the sun, the moon, and the stars. Even the ablest men will be beaten by the farmer in these matters. He knows the state of his immediate surroundings thoroughly well, he can find the directions by looking at the stars in the night, and tell a great many things from the ways of birds and beasts. He knows, for instance, that rain is about to fall when a particular class of birds gather together, and begin to make noise. He knows as much of the earth and the sky as is necessary for his work. As he has to bring up his children, he must know something of Dharma Sastra. Since he lives under the broad open sky, he easily realises the greatness of God. Of course, all men cannot be farmers, nor is this book written for them. We have however, described the life of the farmer, as we are convinced that it is the natural life for man. To the extent [Pg 61] to which we deviate from these natural conditions must we suffer in health. From the farmer’s life we learn that we should work for at least 8 hours a day, and it should involve mental work as well. Merchants and others leading a sedentary life have indeed, to do some mental work, but their work is too one-sided and too inadequate to be called exercise.