The first question that we will discuss is, how much exercise is needed every day, how much will give the greatest benefit, and how much is positively injurious?
And on the threshold we are met with the greatest difficulty of the whole subject; for persons vary extremely in their endurance of exercise, and a walk which would be insufficient for one person may be infinitely beyond the powers of a second to endure. We cannot lay down a rule in this particular. Every person must find out for herself what amount of exercise she must indulge in daily. For a perfectly healthy girl of sixteen to twenty, three to five miles’ walk daily, or an hour’s bicycling, or, if outdoor exercise is not permissible, half an hour’s gymnastic exercise is the minimum amount of exercise which she should take daily.
Ever so many people have an idea that you can lay in a stock of exercise, as you can fill a coal-cellar, and draw on the reserve when you are too lazy to renew the supply. These persons will tell you, “I do all my walking on one day, so that there is no necessity for me to go out any other day in the week. I walk twenty-one miles on that day, that is three miles for each day in the week, so I am all right on this score.” Now just consider one moment what you are doing, and you will agree with us that your method is not only fallacious, but exceedingly harmful.
Suppose that you eat on an average two pounds’ weight of food a day. Do you think that it would be equally beneficial to take the fourteen pounds of food on one day and then have six days’ starvation? Some animals can do this, but man is not fitted for living in this way. With the usual logic evinced by most people when they are contradicted, we are at once answered, “Oh, if what I do is no good, as I cannot take exercise when I like, I shall not go out at all!” Evidently concluding that she takes care of her own health out of consideration for our feelings!
You must be a physician to hear this form of argument without smiling. Perhaps you would feel inclined to answer this lady, “Well, it does not matter to me what you do. It is your health, not ours, that is at stake.” So, indeed, would we like to answer; but if we did, what would be the good of us? No, we will not offend this lady; we will wait till to-morrow, when she will have come to the same way of thinking as ourselves.