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CHAPTER III.

BREATHLESSNESS-(continued).

Mechanism of Breathlessness-Reflex Disturbances of the Respiratory Movements-Physical Sensations and Moral Impressions Stammering Respiration -- Why we become less Breathless at a Fencing-School than in a Duel-Reflexes due to Carbonic Acid-Reflexes are at first Useful; they become Dangerous when Exaggerated-Dangers of Instinctive Movements-Part played by the Heart in Breathlessness--Active Congestions-Fatigue of the Heart-Muscle and Passive Congestion of the Lungs-The Influence of the Heart is Secondary -Cessation of Breathlessness notwithstanding the Persistence of Circulatory Disturbances after Exercise-Personal Observation; the Ascent of Canigou-Effort; its part in Breathlessness-Prompt Advent of Breathlessness in Wrestling—Sprint Running and Long-Distance Running-Our observations on the Rhythm of Respiration during Breathlessness-Inequality of Expiration and Inspiration during Breathlessness; Causes of this Inequality-Serious Phenomena of BreathlessnessAction of Carbonic Acid on the Muscular Fibres of the Heart.

THE essential condition of respiration is the presence in the lungs of atmospheric air and of venous blood, in order that the inspired air may give up its oxygen to the blood, and that the blood may rid itself, in exchange, of its carbonic acid. It is evident that any obstacle to the circulation of blood in the pulmonary capillaries or to the free entrance of air into the pulmonary air-cells, will render the respiratory act incomplete.

Now violent exercise causes a disturbance in the respiratory movements which renders them less efficient in drawing air into the chest, at the same time as it produces in the vascular system disturbances capable of hindering the pulmonary circulation.

Each of these two effects deserves attentive study.

J.

Exercise may have a direct action on the respiratory movements, for many muscular actions are performed with the aid of the muscles of the thorax or the back. These muscles, being used in the work, are momentarily distracted from their function as respiratory muscles. They can even stop respiration when they take their fixed point at the ribs for the purpose of moving the upper limbs. Effort, which we discussed at length in the chapter on Movements, is the type of the actions which stop respiration by fixing the thorax.

This action has important consequences on the circulation of the blood, and it is in this way that it especially affects the respiratory function. But it also momentarily hinders the interchange of gases, and this usually at a time when it is most needed. Stoppage of respiration during repose has no grave consequences, because it is always followed by a compensatory effect, by a series of longer and deeper respirations, which promptly eliminate the carbonic acid, of which the quantity retained in the body cannot be excessive while the muscles are at rest. But if the effort has taken place during work, it happens that the working of the lungs is hindered just at the moment when their action ought to be increased; the suspension of respiration shuts the passage by which carbonic acid ought to be eliminated, at the very time when the muscles are producing three or four times as much of this gas as usual.

Respiration, which hardly answered the needs of the system while the lungs were freely performing their work, becomes suddenly insufficient when the thoracic movements are so hindered. Thus the repeated stoppage of respiration during work may become a very efficient cause of dyspnoea, while in a state of repose it produced but a passing disturbance.

But effort, and the other muscular actions capable of suspending or hindering the play of the ribs, are not the

most frequent causes of the respiratory troubles which we observe during exercise. Respiration is often profoundly modified in its rhythm, its amplitude, and its frequency, without it being possible for us to consider these disturbances as a result of the direct action of the exercise performed. Very often we see that exercises, whose performance does not involve the use of the thoracic muscles, nevertheless profoundly affect the thoracic movements.

It is then by a reflex action that we must account for this indirect effect of exercise.

Reflex actions, capable of modifying the rhythm of respiration, have very various origins, and the lungs are very frequently exposed to their effects, being the most impressionable of all organs. In order fully to understand the reflex effects to which the lungs are subject, we must recall the fact that powerful impressions in general, whether physical or moral, tend to produce involuntary movements, and that these movements may take place just as much in the muscles of organic as in those of animal life.

When we pass near a room in which a person is taking a cold shower-bath for the first time, we hear sighs and suppressed groans. These inarticulate sounds, which resemble cries of distress, are simply reflex actions. The sensation of cold which the water causes when applied to the chest-walls is transmitted to the nerve-centres as a stimulus which produces abrupt expiratory and inspiratory efforts. The air is violently drawn into the chest, or driven out from it in an irregular manner, and causes in its passage vibrations of the vocal cords without the influence of the will. If the impression produced by the cold water is too strong, the reflex action may culminate in a complete stoppage of respiration: it becomes impossible for the air to enter the chest, or, having entered, to get out again. Hence there is a kind of distress, a momentary suffocation which makes hydrotherapeutics very painful at first to impressionable patients.

Every violent physical sensation, wherever situated,

will re-act upon the lung; every powerful moral emotion, whatever its cause, will also make its influence felt on the respiratory function. Joy, sorrow, fear, can produce reflex effects on the respiratory movements which we call a laugh, a sob, a sigh, a cry.

Every time that the rhythm of respiration is disturbed, breathlessness is produced, even in the condition of muscular repose. Moreover, very often, causes of a moral order come to increase the tendency to breathlessness while performing an exercise. An exercise which is performed with tranquil breathing if the mind is free from care, promptly produces respiratory disturbances if the mind is brooding and pre-occupied.

Those who have acted as seconds in a duel to men accustomed to the use of the sword, know that they become breathless in the duel much more quickly than they do in a fencing school. Yet their movements are more prudent, more limited; they make no violent attack, and they watch more than move; they expend less force, but their rapiers have sharp points.

Depressing emotions make their effects felt on the respiration of animals as well as of man. A sensitive horse which is badly used when at work, or even roughly spoken to, quickly becomes breathless.

For the same reason, wild animals can be caught, when hunted, by domestic animals, in spite of their being more accustomed to fatigue; the dog is incomparably less swift than the hare, but is able to catch it: the fright of the hunted animal disturbs its breathing and robs it of much of its strength,

Moral impressions, like physical sensations, can only lessen the respiratory power by reflex effects which disturb the regular working of the pulmonary air-current. Under the influence of fear we see the movements of the chest, now quickened beyond measure, now slackened, and momentarily stopped, now following at irregular intervals. The defect of co-ordination, the disorder of the respiratory movements which we observe under the influence of fright, much resembles the incoherence in the movements of the lips which prevents a man, deeply

moved, from clearly articulating his words. that depressing emotions can bring on stammering respiration.

The disorder of the respiratory movements destroys the regularity of the gas interchange which takes place in the lungs between the venous blood and the atmospheric air, and thus profoundly hinders the function of aeration of the blood. When the respiration is irregular, the carbonic acid produced by work cannot be eliminated as fast as it is formed, and oxygen cannot be introduced in proportion to the needs of the system; hence the respiratory need is unsatisfied and breathlessness comes

on.

Moral impressions, then, add their influence to that of work in the production of breathlessness, not by increasing the production of carbonic acid, but by checking its regular elimination. The more impressionable the subject, the more easily do emotions influence his respiratory actions. Hence the superiority in certain bodily exercises of men who are calm and masters of themselves. The fear of being beaten, the annoyance of seeing himself passed for a moment, may diminish the respiratory power of an athlete, otherwise very vigorous, but too impressionable, and make him lose the prize for running or rowing.

There is a striking resemblance between the respiratory disturbances due to a violent moral impression, and those which result from a powerful physical sensation. The analogy is just as striking if we compare the modifications produced by a very strong emotion in the working of the lungs, and those produced by too violent an exercise. If we find ourselves before a man panting from terror, we might fancy he was out of breath from fast running. In both cases there is the same picture: breathing irregular, speech interrupted, complexion livid.

In a man overcome by a powerful physical impression, such as a cold shower-bath, in a man carried away by fear, and in a man breathless from running, there is a common element capable of disturbing respiration; there