THE CARE OF THE HEART-PUMP AND ITS PIPE-LINES
The Effect of Work upon the Heart. Whatever else in this body of ours may be able to take a rest at times, the heart never can. When it stops, we stop! Naturally, with such a constant strain upon it, we should expect it to have a tendency to give way, or break down, at certain points. The real wonder is that it breaks down so seldom. It has great powers of endurance and a wonderful trick of patching up break-downs and adjusting itself to strains.
Every kind of work, of course, done in the body throws more work upon the heart. When we run, or saw wood, our muscles contract, and need more food-fuel to burn, and pour more waste-stuff into the blood to be thrown off through the lungs; so the heart has to beat harder and faster to supply these calls. When our stomach digests food, it needs a larger supply of blood in its walls, and the heart has to pump harder to deliver this. Even when we think hard or worry over something, our brain cells need more blood, and the ever-willing heart again pumps it up to them. This is the chief reason why we cannot do more than one of these things at a time to advantage. If we try to think hard, run foot races, and digest our dinner all at one and the same time, neither head, stomach, nor muscles can get the proper amount of blood that it requires; we cannot do any one of the three properly, and are likely to develop a headache, or an attack of indigestion, or a "st.i.tch in the side," and sometimes all three. So the circulation has a great deal to do with the intelligent planning and arranging of our work, our meals, and our play. If we are going to increase our endurance, we must increase the power of our heart and blood vessels, as well as that of our muscles. The real thing to be trained in the gymnasium and on the athletic field is the heart rather than the muscles.
Fortunately, however, the heart is itself a muscle, alive and growing, and with the same power of increasing in strength and size that any other muscle has. So that up to a proper limit, all these things which throw strain upon the heart in moderate degree, such as running, working, and thinking, are not only not harmful, but beneficial to it, increasing both its strength and its size. The heart, for instance, of a thoroughbred race-horse is nearly twice the size, in proportion to his body weight, of the heart of a dray-horse or cart-horse; and a deer has more than twice as large a heart as a sheep of the same weight.
[Ill.u.s.tration: THE SCHOOL PHYSICIAN EXAMINING HEART AND LUNGS]
The important thing to bear in mind in both work and play, in athletic training, and in life, is that this work must be kept easily within the powers of the heart and of the other muscles, and must be increased gradually, and never allowed to go beyond a certain point, or it becomes injurious, instead of beneficial; hurtful, instead of helpful. Over-work in the shop or factory, overtraining in the gymnasium or on the athletic field, both fall first and heaviest upon the heart.
Importance of Food, Air, and Exercise. At the same time, the system must be kept well supplied through the stomach with the raw material both for doing this work and for building up this new muscle. When anyone, in training for an event, gets "stale," or overtrained, and loses his appet.i.te and his sleep, he had better stop at once, for that is a sign that he is using more energy than his food is able to give him through his stomach; and the stomach has consequently "gone on a strike."
How to Avoid Heart Overstrain and Heart Disease. The way, then, to avoid overstrain and diseases of the heart and blood vessels is:--
First, to take plenty of exercise, but to keep that exercise within reasonable limits, which, in childhood, ought to be determined by a school physician, and in workshops and factories by a state factory physician.
Second, to take that exercise chiefly in the open air, and as much of it as possible in the form of play, so that you can stop whenever you begin to feel tired or your heart throbs too hard--in other words, whenever nature warns you that you are approaching the danger line.
Third, to keep yourself well supplied with plenty of nutritious, wholesome, digestible food, so as to give yourself, not merely power to do the work, but something besides to grow on.
Fourth, to avoid poisonous and hurtful things like the toxins of infectious diseases; and alcohol, tobacco, and other narcotics, which have a harmful effect upon the muscles, valves, or nerves of your heart, or the walls of your blood vessels.
Fortunately, the heart is so wonderfully tough and elastic, and can repair itself so rapidly, that it usually takes at least two, and sometimes three, causes acting together, to produce serious disease or damage. For instance, while muscular overwork and overstrain alone may cause serious and even permanent damage to the heart, they most frequently do so in those who are underfed, or badly housed, or recovering from the attack of some infectious disease. While the poisons of rheumatism and alcohol will alone cause serious damage to the valves of the heart and walls of the blood vessels, yet they again are much more liable to do so in those who are overworked, or underfed, or overcrowded.
The Disease of the Stiffening of the Arteries. The points at which our pipe-line system is most likely to give way are the valves of the heart, and, more likely still, the muscles of the heart wall and of the walls of the blood vessels. These little muscles are slowly, but steadily, changing all through life, becoming stiffer and less elastic, less alive, in fact, until finally, in old age, they become stiff and rigid, turning into leathery, fibrous tissue, and may even become so soaked with lime salts as to become brittle, so that they may burst under some sudden strain. When this occurs in one of the arteries of the brain, it causes an attack of _apoplexy_, or a "stroke of paralysis." Overstrain, or toxins in the blood, may bring about this stiffening of the arteries too soon, and then, we say that the person is "old before his time." A man is literally "as old as his arteries."
The causes which will hasten the stiffening of the arteries are, first of all, prolonged overwork and overstrain,--due especially to long hours of steady work in unwholesome shops or surroundings; second, the presence in the blood of the poisons of the more chronic infectious diseases, like tuberculosis; third, the waste products that are formed in our own body, and are not properly got rid of through lungs, skin, and kidneys; and fourth, the use of alcohol, tobacco, and other narcotics.
The Bad Effects of Alcohol. Alcohol is particularly likely to damage the walls of the blood vessels and the heart, first, because it is a direct poison to their cells, when taken in excess, and often in what may appear to be moderate amounts, if long continued; secondly, because it is frequently taken, especially by the poorer, underfed cla.s.s of workers, as a subst.i.tute for food, causing them literally to "spend their money for that which is not bread," and to leave their tissues half-starved; and thirdly, because, by its narcotic effects, it decreases respiration and clogs the kidneys and the skin, thus preventing the waste products from leaving the body.
How the Heart Valves may be Injured. The valves of the heart are likely to give way, partly because they are under such constant strain, snapping backward and forward day and night; and partly, because, in order to be thin enough and strong enough for this kind of work, they have become turned, almost entirely, into stringy, half-dead, fibrous tissue, which has neither the vitality nor the resisting power of the live body-stuffs like muscles, gland-cells, and nerves. They are so tough, however, that they seldom give way under ordinary wear and tear, as the leather of a pump valve, or of your shoes, might; but the thing which damages them, nine times out of ten, is the germs or poisons of some infectious disease.
These poisons circulating through the blood, sometimes set up a severe inflammation in the valves and the lining of the heart. Ulcers, or little wart-like growths, form on the valves; and these may either eat away and destroy entirely parts of the valves or, when they heal, leave scars which shorten and twist the valves out of shape, so that they can no longer close the openings. When this has happened, the heart is in the condition of a pump which will not hold water, because the leather valve in its bucket is broken or warped; and we say that the patient has _valvular_ or _organic_ heart disease.
The disease which most frequently causes this serious defect is rheumatism, or rheumatic fever; but it may also occur after pneumonia, typhoid, blood poisoning, or even after a common cold, or an attack of the grip. This is one of several reasons why we should endeavor, in every way, to avoid and stop the spread of these infectious diseases; not only are they dangerous in themselves, but although only two of them, rheumatism and pneumonia, frequently attack the heart, all of them do so occasionally, and together they cause nearly nine-tenths of all cases of organic heart disease.
Should you be unfortunate enough to catch one of these diseases, the best preventive against its attacking the heart, or causing serious damage, if it does, is a very simple one--rest in bed until the fever is all gone and your doctor says it is perfectly safe for you to get up; and avoid any severe muscular strain for several months afterward.
This is a most important thing to remember _after all infections and fevers_, no matter how mild. Even where the heart valves have been seriously attacked, as in rheumatism, they will often recover almost completely if you keep at rest, and your heart is not overtaxed by the strain of heavy, muscular work, before it has entirely recovered. Ten days" "taking it easy" after a severe cold, or a bad sore throat, may save you a serious strain upon the heart, from which you might be months or even years in recovering.
But even where serious damage has been done to the heart, so that one of its valves leaks badly, nature is not at the end of her resources. She simply sets to work to build up and strengthen and thicken the heart muscle until it is strong enough to overcome the defect and pump blood enough to keep the body properly supplied--just as, if you are working with a leaky pump, you will have to pump harder and faster in order to keep a good stream of water flowing. It is astonishing how completely she will make good the loss of even a considerable part of a valve.
Doctors no longer forbid patients with heart disease to take exercise, but set them at carefully planned exercise in the open air, particularly walking and hill-climbing; at the same time feeding them well, so as to a.s.sist nature in building up and strengthening the heart muscle until it can overcome the defect. In this way, they may live, with reasonable care, ten, fifteen, or twenty years--often, in fact, until they die of something else.
Don"t worry about your heart if it should happen to palpitate, or take a "hop-skip-and-jump" occasionally. You will never get real heart disease until you have had some fever or serious illness, which leaves you short of breath for a long time afterward.
Danger to the Heart through the Nervous System. The other chief way in which the heart may be affected is through the nervous system. Being the great supply pump for the entire body, it is, of course, connected most thoroughly and elaborately by nerve wires with the brain and, through it, with every other organ in the body. So delicately is it geared,--set on such a hair-trigger, as it were,--that it not only beats faster when work is done anywhere in the body, but begins to hurry in antic.i.p.ation of work to be done anywhere. You all know how your heart throbs and beats like a hammer and goes pit-a-pat when you are just expecting to do something important,--for instance, to speak a piece or strike a fast ball,--or even when you are greatly excited watching somebody else do something, as in the finish of a close race.
Two-thirds of the starts and jumps and throbbings that the heart makes, are due to excitement, or nervous overstrain, or the fact that your dinner is not digesting properly; and they don"t indicate anything serious at all, but are simply useful danger signals to you that something is not just right.
In work and in athletics for instance, this rapid and uncomfortably vigorous action of the heart is one of nature"s best checks and guides.
When your heart begins to throb and plunge uncomfortably, you should slow up until it begins to quiet down again, and you will seldom get into serious trouble. The next time you try the same feat, you will probably find that you can go a little farther, or faster, without making it throb. Indeed, getting into training is very largely getting the heart built up and educated, so that you can run or play, or wrestle hard without overtaxing it. Whatever you can do within the limits of your heart is safe, wholesome, and invigorating; whatever goes beyond this, is dangerous and likely to be injurious.
[Ill.u.s.tration: ROWING IS A SPLENDID EXERCISE FOR HEART AND LUNGS]
Occasionally, however, some of the nerves which control the heart become disturbed or diseased so that, instead of the heart"s simply beating harder and faster whenever more blood is really needed, it either throbs and beats a great deal harder and faster than is necessary, or goes racing away on its own account, and beats "for dear life," when there is no occasion for it, thus tiring itself out without doing any good, and producing a very unpleasant feeling of nervousness and discomfort. This may be due to overwork, whether with muscles or brain; or to worry or loss of sleep, in which case it means that you must put on the brakes, take plenty of rest and exercise in the open air, and get plenty of sleep. Then these danger signals, having accomplished their warning purpose, will disappear.
Other Causes of Heart Trouble. At other times, this palpitation is due to the presence of poisons in the blood, either those of infectious disease, or of certain waste products produced in the body in excess, as, for instance, when your digestion is out of order, or your skin, kidneys, and bowels are not working properly; or it is due to tea, coffee, or tobacco.
Effects of Tea and Coffee. Tea and coffee, if taken in excess, will sometimes produce very uncomfortable palpitation, or rapid over-action of the heart, with restlessness and inability to sleep. They usually act in this way only when taken in large amounts, or upon a small percentage of persons who are peculiarly affected by them; and this palpitation is seldom serious, and disappears when their excessive use is stopped.
Tobacco and its Dangers to the Heart. Tobacco has a very injurious effect upon the nerves of the heart in the young, making them so irritable that the heart will beat very rapidly on the least exertion; so that gradually one becomes less and less inclined to attempt exertion of any sort, whether bodily or mental, and falls into a stagnant, stupid sort of condition which seriously interferes with both growth and progress.
In other cases, tobacco dulls and deadens the nerves controlling the heart, as it does the rest of the nervous system and the brain, so that the smoker feels as if nothing were worth while doing very hard, and it becomes difficult for him to fix his mind upon a subject. At the same time, it dulls the appet.i.te so that one takes less wholesome food; and it checks, or clogs up, the sewer-pipes of the skin, the liver, and the kidneys.
Of course, as you know, all trainers and coaches, even though they be habitual smokers themselves, absolutely forbid tobacco in any form to athletes who are training for a contest, on account of its effects upon the nervous system and the heart.
A certain percentage of individuals are peculiarly susceptible to tobacco, so that it has a special poisonous effect upon the nerves of the heart, causing a rapid pulse and shortness of breath, known as _tobacco heart_. This is not of very common occurrence; but it is exceedingly troublesome when it does occur, and it takes a long time to get over it, even after the use of tobacco has been stopped entirely.
Sometimes it leads to permanent damage of the nerves and of the heart.
Give your heart plenty of vigorous exercise, but don"t make it beat uncomfortably hard. Give it plenty of food, sleep, and fresh air; _avoid poisoning it_, either with the toxins of diseases, or with your own waste-poisons, or alcohol, or tobacco; and it will serve you faithfully till a good old age.
CHAPTER XIII
HOW AND WHY WE BREATHE
Life is Shown by Breathing. If you wanted to find out whether a little black bunch up in the branches of a tree were a bird or a cl.u.s.ter of leaves, or a brown blur in the stubble were a rabbit or a clod, the first thing you would probably look for would be to see whether it moved, and secondly, if you could get close enough without its moving away, whether it were breathing. You would know perfectly well if you saw it breathing that it was alive, and that, if it were not breathing at all, it would probably be dead, or very nearly so.
Why is breathing so necessary to life that it lasts practically as long as life does, and when it stops, life stops too? Animals can stop eating for days, or even weeks, and yet live, especially if they were fairly fat when they began to fast. Indeed, some animals, like woodchucks, bears, and marmots, will go to sleep in the fall, and sleep right on through to spring without eating a mouthful. But if any animal or bird is prevented from breathing for three minutes, it will die.
Short Storage Supply of Air. There is a difference between the kind of things that you take in when you breathe and the kind of things you take in when you eat or drink. Food and drink are solids and liquids; and the body is a great sponge of one soaked full of the other, so that large amounts of food and water can be stored up in the body. But what you take in when you breathe is, of course, air--which is neither a solid nor a liquid, but a gas, very light and bulky. Of gases the body can soak up and hold only a very small amount; so its storage supply of them will be used up completely in about three minutes, and then it dies if it cannot get more air.
Why our Bodies Need Air-Oxidation. The body is made up of millions of tiny living animals called cells, which eat the food that is brought to them from the blood and pour their waste and dirt back again into the same current. Now, what would happen if we were to throw all the garbage from the kitchen, and the wash water from the kitchen sink, and the dirty water from the bathroom right into the well out of which we pumped our drinking water? We should simply be poisoned within two or three days, if indeed we could manage to drink the disgusting mixture at all.
That is exactly what would happen to our body cells if they were not provided with some way of getting rid of their waste and dirt.
[Ill.u.s.tration: THE GREAT ESSENTIAL TO LIFE--AIR
If the air, supplied to the diver through the tube, is cut off for three minutes, or even less, the diver cannot live.]
Part of the waste that comes from our body cells is either watery, or easily dissolved in water; and this is carried in the blood to a special set of filter organs--the liver and the kidneys--and poured out of the body as the _urine_. Another part of it, when circulating through the skin, is pa.s.sed off in the form of that watery vapor which we call perspiration, or sweat. But part of the waste can be got rid of only by burning, and what we call burning is another name for combining with oxygen, or to use one word--_oxidation_; and this is precisely the purpose of the carrying of oxygen by the little red blood cells from the lungs to the deeper parts of the body--to burn up, or oxidize, these waste materials which would otherwise poison our cells. When they are burnt, or oxidized, they become almost harmless.
Why the Red Cells Carry only Oxygen to the Body. But why do not the red cells carry air instead of just oxygen? This is simply a clever little economy of s.p.a.ce on nature"s part. As a chemist will tell you the air which we breathe is a mixture of two gases--one called nitrogen and the other oxygen; just as syrup, for instance, is a mixture of sugar and water. Then too, as in syrup, there are different amounts of the two substances in the mixture: as syrup is made up of about one-quarter sugar and three-quarters water, so air is made up of one-fifth oxygen and four-fifths nitrogen. Now the interesting thing about this mixture, which we call air, is that the only really "live" and vital part of it for breathing purposes is the one-fifth of oxygen, the four-fifths of nitrogen being of no use to our lungs. In fact, if you split up the air with an electric current, or by some other means, and thus divide it into a small portion of pure oxygen (one-fifth), and a very much larger portion (four-fifths) of nitrogen, the latter would as promptly suffocate the animal that tried to breathe it as if he were plunged under water.[18]