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EFFECT OF EXERCISE ON NUTRITION.

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occur, are dependent on certain derangements of the physical condition of the brain-irregular distribution of blood, local congestion, or interrupted circulation from functional sluggishness,-and man may often be literally said to walk away from his cares, and secure, by the mere exercise of his limbs, bright and happy thoughts and feelings.

Muscular exercise is enabled to influence the circulation of the blood, and promote all its ulterior uses in the economy, not only by its direct effect on the arterial system, and the influence of the mechanical pressure of the contracting fibres on the contained and contiguous arterial capillaries, but, in some degree, likewise, by reason of the veins being to some considerable extent provided with valves, particularly those veins which have to carry the blood in a direction opposite to that of its gravity. The consequence of this is, that external pressure on these vessels assists in propelling the contents onwards,-the valves preventing their retrogression, as the vis à tergo does in the case of the arteries. The thoracic duct is, moreover, likewise furnished with these valves, at short distances; and thus, every movement of the trunk of the body, every full respiration, may be readily conceived to influence and promote the passage of the chyle through the lymphatic system, and cause it to be conveyed more quickly and readily to the current of the circulation.

The expenditure of azotised matter produced by all the processes of the animal economy, and the

large degree in which this is increased by muscular exercise, become important among the reasons for attention to this as a means of health, as a direct and powerful agent in carrying away effete matters from the system, and promoting the efficient compensation for the alimentation of the body.

The effect of muscular exercise on the great process of respiration, remains to be mentioned among its causes of powerful action on the economy. Perhaps, in consequence of the greater velocity, or the greater volume, in which exercise causes the blood to be driven through the tissue of the lungs, stimulating, as this may be inferred to do, the nerves that minister to the purposes of respiration, the respirations become, in a degree corresponding to the quickened or more energetic circulation of the blood, more quick and more deep; and the oxygenation of the blood is in the same ratio promoted, the consumption of carbon increased, and the animal heat maintained, and more thoroughly diffused through the distant parts, and to the surface of the body. The marked effect of muscular exercise in increasing the heart's action, either as to its quickness, or its power, or both, and in stimulating to more energetic action the muscles concerned in respiration, although perhaps mainly explicable on the principle of the more rapid return of blood to the heart, may likewise be partly referred to the general effect of increased capillary circulation on the whole of the fibrous tissues, and the consequent stimulus to all the moving apparatus, whether directly voluntary

EFFECT OF EXERCISE ON SENSATION.

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or otherwise, to an increased exertion; and to this probable influence, may be referred some of the good effects of exercise on the organs of secretion and excretion.

But muscular exercise is a direct source of pleasure to every one not suffering from diseased action. Every one must have felt this. The effect of using the muscles of voluntary motion, when all the processes of the economy are being justly and healthily performed, is to impart a marked and grateful stimulus to the sentient nerves of the part, and a corresponding and grateful stimulus to the nervous system generally, sufficiently noticeable by the mind when studious of its analysis, and always ministering indirectly to the happiness of the individual, colouring and brightening the thoughts and feelings. So much is this believed to be the case by some, that it has been asserted—a man may use his limbs too much to leave him in the enjoyment of his fullest capability of pure and abstract thought, and to the extent of making him unduly imaginative. Although this may well be matter of doubt, the fact and its wise and benevolent intention remain unaffected: that man derives an immediate pleasurable sensation from using his voluntary muscles, which not only gives to labour a zest, and even to monotonous movements some degree of enjoyment, but produces a re-action on the mind itself; embellishing a life of virtuous toil with a degree of physical enjoyment, and mental energy, buoyancy, and hopeful lightheartedness, that can never be afforded in a like

degree to the drones-the mere "fruges consumere nati" of the human hive.*

To be thus largely useful to the well-being of the economy, the exercise must not be confined to any set or series of muscular movements; but, as far as possible, should bring into play all the moving powers of the body. It may be said, in general terms, that the greater the number of muscles concerned in the exercise, and the more completely it

"The first physicians by debauch were made;
Excess began, and sloth sustains the trade.

By chase our long-liv'd fathers earn'd their food;
Toil strung the nerves and purified the blood;
But we, their sons, a pamper'd race of men,
Are dwindled down to three-score years and ten.
Better to sweat in fields for health unbought,
Than fee the doctor for a nauseous draught.
The wise for cure on exercise depend,

God never made his work for man to mend."

DRYDEN.

"There is a story in the Arabian Nights' Tales, of a king who had long languished under an ill habit of body, and had taken abundance of remedies to no purpose. At length, says the fable, a physician cured him by the following method: he took an hollow ball of wood, and filled it with several drugs; after which he closed it up so artificially that nothing appeared. He likewise took a mall, and after having hollowed the handle, and that part which strikes the ball, he inclosed in them several drugs after the same manner as in the ball itself. He then ordered the sultan, who was his patient, to exercise himself early in the morning with these rightly prepared instruments, until such time as he should sweat: when, as the story goes, the virtue of the medicaments perspiring through the wood had so good an influence on the sultan's constitution, that they cured him of an indisposition which all the compositions he had taken inwardly had not been able to remove. This Eastern allegory is finely contrived to show how beneficial bodily labour is to health, and that exercise is the most effectual physic."-Spectator, No. 195.

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involves the full contraction of each muscle, the more influential will the exercise be.

The practical deductions from this remark are many. Riding on horseback is shewn to be a more important agent than being drawn in a carriage; walking to have more effect on the system than riding; quick walking than slow; running than either. A combination of several of these,-as each has its favourite sets of muscles, which it uses most,is more influential than any one by itself. It follows, moreover, that exercise of the arms is only second in importance to that of the legs; and, consequently, that some simple gymnastics, such as raising the body from the ground by grasping a suspended cord, or a fixed transverse pole, with the hands, or even swinging the arms round like the sails of a windmill,-or thrusting them backwards and forwards, is an excellent auxiliary to walking exercise, or to running, and one which most men of sedentary habits ought to have recourse to, if all the purposes are to be fulfilled which exercise is capable of subserving in the economy.

What is called the hand-swing, or triangle, forms an excellent mode of exercise for the arms. It consists simply of two ropes, secured together at one end to a transverse beam of the ceiling of a room, or to a similar beam placed between the walls of the play-ground, the other extremities of the ropes being connected securely by a cross-bar of wood for the hands to grasp; the apparatus being fixed at such a height, that the bar of wood is only just within reach of the

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