The effect of active exercise on the heart, as it is well known, is to make it beat faster; by this the blood is driven through the body at a quicker rate than usual. Sometimes, when the effort is unusually severe, there is a disturbance of the regular balance between the heart and the lungs. There is thus produced an irregular or unequal action of the former, causing what is known as "loss of wind," which is, however, soon restored by resting.
There is an excessive flow of blood to the surface of the body, causing it to redden, and at the same time the perspiration is greatly increased. It is on account of this latter moisture opening up the pores of the skin that the good effects of exercise are chiefly due. The perspiration consists mainly of water containing different salts and organic matters. It is found by experiment that the amount of water passing through the lungs and skin is usually doubled even with moderate exertion.
The result of moderate exercise in benefiting the nervous system is well known, and the effect of a gentle walk in making the ideas flow through the brain is a matter of common observation. At the same time, it must be borne in mind that exercise, when carried to the verge of fatigue, compels inactivity of the brain for a time, since Nature must have repose. But when carried out in moderation with a view of improving the condition of the body, it conduces to the salubrity of the brain as well, for the latter organ shares in the health of the former. The only thing to guard against is irregular and fitful doses; thus it is far better to take a little in moderation daily, than to attempt to make one day's exercise suffice for the rest of the week.
It follows from the foregoing, therefore, that without exercise a perfect state of health is an impossibility. There can be no proper bodily health unless there be daily exercise. It is the same with everybody, no matter what the condition of life may be. Exercise is quite as necessary for the well-to-do man as it is for him who is not so circumstanced. The laws of health cannot be violated, and all the money in the world will not atone for neglect in this respect. Exercise is not a matter that can be carried out by proxy. No; each one must take his own exercise, and he derives all the benefit for himself.
It is a fortunate thing, then, that most people have to earn their own living, for the exertion thereby entailed is actually necessary for health. Yet, while this is the case with those who live by their bodily labour, it hardly applies to those who are more dependent upon mental work. For instance, the latter include literary men and journalists, the members of the professions, and those of the vast commercial world - all, indeed, who have brain strain and clerical occupations. In their case the great fault is that they use their heads too much and their limbs too little. For them walking is one of the very best means of obtaining health, and it should be regularly and systematically practised.
It has been said that no man under sixty, unless he be kept walking while at his work, should walk less than six or eight miles a day, if he wishes to keep well and have healthy children. In the cooler weather in Australia these are certainly suitable distances, but in the hot months half these amounts will be found sufficient, and they had better be carried out in the cool of the evening. Then again, for those over sixty it has been well observed that a daily walk is still the best means of promoting health. But the walk must always be proportionate to the strength, and should be done at nothing more than a moderate pace, if a man wishes to take care of his blood vessels.
There is another matter which calls for notice, and it is that of early morning exercise. Now, I am quite willing to admit that there are many who derive great benefit from their early morning swim, their matutinal walk, or their tennis before breakfast. But it should be distinctly borne in mind that there are others with whom such early morning exercise does not agree. They get as a result a weary, languid feeling which lasts throughout the entire day. Now, they are apt to imagine it is the exercise in itself which produces this effect. But the truth is, it arises from the time of day at which the exercise is taken, and is not due to the exertion at all. It must not be forgotten, therefore, that while many people derive the greatest advantage from early morning exercise, yet there are others for whom it is altogether unsuitable. But, on the other hand, the latter will obtain every possible benefit by taking their allowance of exercise at some other period of the twenty-four hours.
There are other forms of exercise besides walking, and these have their good points. Riding is, of course, invaluable, especially in cases of sluggish liver. As it has been wittily observed, the outside of a horse is the best thing for the inside of a man. In the cool months in Australia riding is a real pleasure, but in the hot season it is hardly so agreeable. Then again, rowing is a magnificent exercise, and has much to recommend it in early adult life. There is no harm whatever in rowing as an exercise, but when it comes to racing that is a different matter. It is the great strain on the heart, together with the excitement which constitute the sources of risk. The other varieties of exercise, namely, gardening, the different games, cricket, football, tennis, etc, need not be particularized as they all subserve the same purposes, and are in consequence very desirable.
In all the preceding I have endeavoured to show that daily exercise is absolutely necessary for the proper maintenance of health. But there is something even more than this. It is that a long life itself is to be ensured by exercise. It is only by exercise, and by exercise alone, that the various organs of the body, the heart, the lungs, the stomach, the liver, etc, are maintained in their normal state of health. Their condition, moreover, is only to be improved by the muscular movements belonging to exercise. The heart itself is intended for action, not for inaction. By action it thrives, and by disuse it becomes weakened. It is so with all the other organs. In conclusion, therefore, it must be said that the whole system can only be kept in perfect health by muscular movements, and that in addition to keeping the body in health exercise actually increases the chances of living to a good old age.