Popular Science Monthly/Volume 64/March 1904/The Conservation of Energy in Those of Advancing Years II
|THE CONSERVATION OF ENERGY IN THOSE OF ADVANCING YEARS. II.|
Developmental Processes in Ageing Tissues; Physiology of Decadence. Senile Involution.
THE brevity of this communication does not warrant a discussion of senility from the standpoint of the physician, but rather a presentation of such facts to the person who is growing old as may prove helpful and suggestive in postponing the more serious results of advancing years. It is, however, important to glance at the manner and processes by which the inevitable end is reached. The clinical picture of approaching death is divided by Tessier into those structural degenerations involving, first, the heart and blood vessels; second, the lungs; third, the kidneys; fourth, the digestive organs, and fifth, the brain. First of the heart, which is now recognized to be the organ which plays the chief part in the ending of life. Before we knew much about the subject it was natural to infer that the heart was chiefly at fault and the common phrase was often used of death by 'heart failure,' one which we now know to be scientifically correct but aforetime vaguely employed. Then discoveries were made that the arteries in the aged were nearly always diseased, and medical thinkers went so far as to assert that all instances of death in old age resulted from the hardening of the arteries. It is true that this is an accompanying phenomenon in most instances, and perhaps in all, but it is recognized to be not the most potent factor in a certain large proportion.
What is to be said here is not meant for a guide to the aged individual by which he may be encouraged to form independent judgments for himself, but rather to act as items of useful information, through which he can better interpret the statements and appreciate the importance of following the directions of his physician.
The heart of a healthy old person has become fatigued in its structure through a decadence of its nerve supply. The pulse is rather quicker than during middle life; it is more or less irregular and becomes increasingly so. In a healthy heart there is, however, a regular irregularity; a normal sequence of alterations in the rhythm and force which is only significant when studied by the trained physician. The phenomenon which is one of the most constant and inevitable, as the effects of age begin to make themselves felt, is shortness of breath on exertion. This has to do more with faults in the action of the circulation and the vasomotor nerves than in the lungs. The old man finds himself distressed in his breathing while undergoing a degree of exertion which aforetime would produce no noticeable effects. The heart muscle is old, relaxed and softened and contracts imperfectly and readily shows exhaustion. This need not produce alarm, but if the condition rapidly increases it may be significant of some important change and should be referred to the medical adviser. In fact, it can not be repeated too often that the more constantly the aged person remains under observation of a wise physician, the more safely can it be promised that he will live happily and long. There is a symptom which is most terrifying and frequently occurs in the aged, and that is a sudden agonizing chest pain, during which the sufferer, unless he be of unusual mental equipoise, feels that he shall instantly die. This may come on suddenly without previous warning and requires the best medical advice, but it almost always passes and may recur many times and is capable of much relief. It may be a symptom of chronic myocardial degeneration.
The lungs also, in most instances, share in the process of death. The changes which occur in the aged lung are degenerative and need have nothing to do with any previously disordered processes in them. Again it may happen that certain changes common in old age take place and prove to be most distressing; the chief of these are asthma, chronic pneumonia and bronchitis. Pneumonia in the aged is a very serious affection, and it is stated that the largest number of deaths in old people are caused, or accompanied by, acute broncho-pneumonia.
The digestive organs sometimes give away while the rest of the organism remains in fairly good condition. Sir William Thomson has written most charmingly upon the digestive disorders of elderly folk, and it would be well for every old person to read his suggestive essays. Unless care is observed in regulating the diet (and the chief point here is rather a reduction in the amount than particularizing as to the items of food taken), distressing phenomena will constantly arise. Fortunately this is easily avoided, although not so readily cured. Sir William Thomson makes the assertion that the disappearance of the teeth is a plain indication of the return to a second childhood, and therefore the food should be of such a character as may not require the assistance of the teeth in mastication. He advises most wisely, although his recommendation can not be taken literally, that the teeth be not replaced by artificial ones, for thereby is a peril lest more food be taken than the organism can dispose of. The fact that the various organs concerned in the elaboration of food share very early in the degenerative changes of age makes it clear that the character of the food taken should be so simple in kind that no great strain would be placed upon these atrophied organs. The gastric juice is secreted in less quantity, so of the pancreatic, the biliary and the intestinal juices. The lessened quantity of bile makes for constipation and the formation of gall-stones and impairs absorption, and assimilation is thus interfered with. The kidneys, the chief source of elimination of a most elaborate series of poisons, become enfeebled in their action and hence should not be overtaxed by either the quantity or the quality of the work they are called upon to perform. Finally the brain may be the part which gives way most prominently, and then we may find hemorrhages into its structure, a softening begins, and alteration in mentality which point the way to more remote and serious changes. The physiology of old age may be described briefly as a progressive diminution in all the functional activities. There is in the life of every normal individual a constant and proportional relationship between the development of parts and tissues and the natural progress toward dissolution. The function which is in most immediate relationship to the reparative power of the cells is the one which will be first affected, so soon as old age begins. The four particular acts of nutrition may be succinctly described as: first, contact of the cell with the nutritive elements; second, the phenomena by which sustenance is drawn from this material, namely, assimilation; third, the changes through which the assimilated products pass, namely, dissimilation; and fourth, the phenomena of the ejectment of the non-assimilated substances. In senescence the first change to be noted in these essential steps in nutrition is to be seen in assimilation. The reparative power of the cells is lessened and the elements of repair tend to be furnished in smaller quantities and soon pass beyond the power of maintaining cellular integrity. Next, there is a diminishing cell resistance leading to atrophy and xerosis. Xerosis (Tessier) is the normal hardening of the tissues in contradistinction to the abnormal sclerosis. With diminution in the power of assimilation there will appear modifications in the normal processes of dissimilation. The difficulties which the cell finds in securing the necessary pabulum tends toward inertia in the phenomena of metabolism. Next the products of incomplete oxidation accumulate, are made difficult to get rid of; they are more damaging to the integrity of the structure of the organ, and the tissues undergoing normal senescence are in constant peril of suffering disease changes. It is the presence of these toxins which places the physiologic processes of senility close to the line of pathology with incomplete oxidation; they tend to accumulate, to infiltrate and to work harm. Chemical changes are less active then, and more poisons form than can be thrown off; gout, rheumatism and their simulants arise. The standards for comparison in the phenomena of waste and repair are not to be formulated. The physician can not know, in the light of present knowledge, just when the equilibrium is lost and when the subject under observation has passed the point where senilization has gone through several changes, and proceeds rapidly, and can not be checked.
Life will flow on with normal energy so long as the noble elements, the more highly differentiated cells, are in excess both in processes and activity. The noble elements are those cells which take upon themselves the preponderating role in accomplishing the function of an organ, in contradistinction to those which play but a secondary part as forming the mechanical support of the organ. Since these can not be replaced in due proportion, function will be interfered with and senescence will begin. Connective tissue now tends to fill all gaps and gradually to invade the tissues, and scleroses will arise, placing obstacles in the way of functional discharge; this constitutes disease. "Inasmuch as the individual is merely an aggregation of special organs adapted to a common existence, the increasing deterioration of these functional activities leads toward gradual deterioration of the individual himself, who will gently fade away out of existence" (Tessier).
The progress of atrophic changes is not regular, either in the general system or in the special organ. All the elements of the mass do not live to the same age. The constituent elements undergo a perpetual restoration, the older disappearing and being replaced by others which have been long maintained in a state of less differentiation, hence of less specialization. As the completed elements disappear the younger ones are matured, hence the compensation is established between atrophy and repair. This movement of partial renovation in tissues is a picture in little of life, the birth of each element, its functional life, senility and death. The explanation of why irregularity should occur in the nutritive activities in the tissues of each organism, and equally in the whole of some organisms, causing individual and constitutional variations, is not so clear. Chemical processes, presumably similar to the small modifications in the cellular arrangements, and the forces that work, must be recognized. In time we may—indeed we must—know what these dynamic features are; then we shall have reached the first step in controlling these variations from a sound working basis. It is certain that these dynamic modifications can not progress indefinitely without producing tangible modifications and alterations in molecular activities; this constitutes disease. Atrophy is an anatomical phase of senility, whose irregular distribution is explained by the inequality of cellular existence, and this is again dependent upon the initial impulse of contraction and upon varying states in the medium, and this by the introduction into the tissues of matters foreign to its normal structure. When this occurs it is degeneration. The study of pathologic changes, by which most of the observations have been made upon the conditions governing senile processes, induces a tendency to start from wrong premises. It is important that these researches should be strongly modified by a comparison between normal and physiologic changes, otherwise right conclusions are obscured. This practical point must never be lost sight of by observers and clinicians in the study of the individual and his ailments. In the study of the processes of the individual the ailments are too frequently the only conditions considered and the normal changes overlooked.
Clinicians recognize what they call diatheses. A diathesis is a tendency toward disease, and many of these can be recognized in their incipience and differentiated in such manner that preventive measures can be employed and earlier changes limited and improved. Disease is the domain of pathology, the study of abnormal conditions induced by changes outside the realm of individual processes. The diathesis gives evidence of a lessened coefficient of resistance, a lowering in noble activities and exhaustion of the powers of repair. This is probably because the power of attraction is not the same in each person and is of variable intensity. Protoplasm has not the same proportions in its composition, hence variations arise in the phases of its evolution. Assuming then the variability in chemic structure, and hence a variable power of attraction in protoplasm, hence, also in the coefficient of resistance, these thoughts will aid in explaining congenital and queer constitutional peculiarities, and often inexplicable differences in races, families and individuals. It is a matter of common observation that in some families senile changes occur much more early than in others, and yet there may be little of degenerative change apparent or probable because of the vigor of the individual. As the gradual steps of growth lead to development, so does the phase of existence called senescence merge insidiously toward the ending called death, through a progressive and insensible diminution in all the organic activities. Death should be regarded as a normal function. Ordinarily it is free from pain and hence should be free from sadness.
Excessive fatness, or polysarcia, is not confined to advancing years, it is observed at all ages; but the quality of the accumulation in early years differs from that seen in late middle life. During the earlier years excessive gain in weight is usually the product of full digestive capacity with a somewhat lessened eliminative power and can be met by reduction in diet and active exercises, and is, as a rule, controllable. With that form of obesity which is not altogether manageable in young people or those on the hither side of middle life we have nothing to do, except in so far as we should discuss this condition and its progress when encountered in later years. Again in women more particularly, there is oftentimes a sudden gain in weight, sometimes to a very annoying and disabling degree, following the change of life. This is an abnormality, and is sometimes based upon pathologic changes in the thyroid gland analogous to myxedema. In men at about the same relative period an enormous gain in weight occasionally arises and is a serious annoyance and anxiety. A few points in regard to the control and reduction of this warrant discussion, although they need not be elaborated. Where this gain in weight seems to be free from any abnormality except difficulties in the elimination or utilization of fat, it is proper to initiate active treatment by careful diet according to the methods of Banting, Ebstien, Oertel, along with specially directed exercises. In persons who are obviously not vigorous, as in those instances where marked anemia is present, there should be a careful search for evidences of disease beginning, or established, and treatment for the condition outlined accordingly. Von Noorden emphasizes the necessity of being on our guard in treating conditions of obesity which arise in women from fifty to sixty years of age. The greatest precautions must be used in dealing with these, because under almost any regime they will lose strength, frequently to an alarming extent, and what is more fail to regain it. The same statement holds good, to a less degree, in men of the same age. It would be interesting to formulate the different kinds and degrees of obesity and the pathologic changes which often accompany this state, forming it may be the cause on which the obesity arises, or again the results, direct or indirect, of the excessive weight. It is enough for our purpose here to offer some directions as to how this objectionable state may be relieved without producing harm. First, it is necessary to bear in mind that under the direct advice and continued attention of the physician is the only safe mode of procedure. Where there is found, as often happens, marked weakness of the heart and circulation the greatest care must be observed, and measures should be adopted having direct regard for the possibilities of the individual and varied from time to time under intelligent supervision. It is always a dangerous thing for persons to undertake their own treatment for obesity if they make use of drugs, because great harm can be done; it may be irretrievable. There is no objection, however, to moderating the diet, increasing exercise, and, above all, to employing systematized physical training for the purpose of improving elasticity in all the tissues. It is only safe to do so under medical advice. Oertel in 1885 and after, has done work which marks an epoch. The principle upon which he proceeds is that even where there is found to be pronounced weakness of the heart muscle, and other disturbances in circulation, these may be met by steadily increasing the amount of physical work done, especially by hill climbing. This walking up slopes has the merit of bringing out skin moisture and taxing the respiratory capacity much more promptly and completely and is more capable of regulation than any other form of exertion, at least any which would be admissible. It is only possible for people relatively young or strong to begin in this way. Our subject is polysarcia in people of advancing years, and hence greater caution must be exercised in outlining activities than for younger folk. The general principles of exercises given at the end of this paper need not be repeated here, but should be read in connection with the measures now to be outlined. In over-stoutness of late middle life, accompanied by good health, it is essential to use first fairly active increasing extensor movements with elasticizing measures, active and passive stretchings, loosening up of the hip joints particularly, and above all, thorough drill in regaining proper attitudes. This should be followed by systematic, accurate training in breathing till a normal capacity is attained, almost never found in stout people unless acquired through teaching. In a paper elsewhere I have elaborated these thoughts (Internat. Med. Magazine, July, 1901).
When we have to do with the fat anemic person vastly more care must be used. The heart in these cases is likely to be infiltrated by fat and the muscular fibers clogged and inelastic, and must be taught slowly to regain their contractile vigor. At first, climbing stairs under direction is about as much as can be attempted, and any house will serve, merely regulating the number of steps walked up and down (both being of benefit) and the rate of speed carefully specified. Tall office buildings serve admirably for the purpose. Polysarcia is such a disabling condition that it is well worth prolonged remedial efforts. Success is possible, and indeed always probable, within limitations. The unaided efforts of the patient can readily lead to harm, sometimes calamity. There is one essential rule in dealing with the cases under consideration, and that is the time for treatment can not be measured by weeks, should not be measured by months and can only safely and satisfactorily be measured by years. One instance will help to illustrate my point. I had a gentleman under my care of sixty-one years of age, who had learned to ride a bicycle before meeting me and found it impossible to use this much because of the distress it produced in breathing. I saw him only rarely at intervals of months, and advised him by letter chiefly in connection with his own physician. He was advised to adopt the rule of riding regularly but briefly on the level roads of his own country place. After some months these short excursions produced no distress. In a year's time he was able to start out upon the open roads, but was compelled to dismount at every small rise of grade. In another year he was able to ride up moderate grades on a good road. At the end of the second year he was riding with comfort and pleasure. At the end of the third year he rode all about the country where the roads were good and for hours at a time. The loss in weight scarcely showed in the first two years, but after that it was sufficiently great to be satisfactory. At the age of seventy-six he feels himself to be all of twenty years younger than when he began.
There is a time about the middle of the life of women which is called the critical period and is supposed to be fraught with many dangers and grave disturbances. This period of the climacteric has been grossly exaggerated, and it is by no means necessary to look forward with dread to the time when menstruation ceases. Man reaches the period of highest development at forty-one years, and woman at thirty-nine. The following seven to ten years may be called the age or epoch of invigoration in both the sexes. The tissues have then become most stable and the nutrition of the body is at its best. It is one of the epochs of development and naturally is accompanied by certain characteristic features. In man these epochs are marked as follows: Dentition, pubescence and the climacteric of age. These are all practically developmental phases, although the last is usually accompanied by degenerative changes in one or another vital organ by which resistance in the tissues is lessened, allowing relatively slight influences finally to cause death. In woman there is generally recognized another, styled the change of life, or menopause. Modern investigations seem to demonstrate beyond a doubt that this change of life is merely a conservative process of nature to provide for a higher and more stable phase of existence, an economic lopping off of a function no longer needed, preparing the individual for different forms of activity, but is in no sense pathologic. It is not sexual or physical decrepitude, but belongs to the age of invigoration, marking the fullness of the bodily and mental powers. There are rather more decided changes in the blood-making and blood-elaborating organs in women, toward the end of life, than in men. Man's greater activity enables him to escape this contrast, because as a rule he has called more upon his motor machinery in using up offer the same degree of resistance to intestinal and other poisons, and the great eliminating organs begin to exhibit a gradual lessening in functional activity. The theories of immunity rest upon the assumption of the presence of some proteid body in the blood which endows the whole system with powers of resistance to toxins. Exhaustion, especially such as is induced by the emotions, fatigue, grief, anger and fear, are well known to weaken the protective power of these mysterious agencies. At the time of the so-called change of life, woman is usually burdened with the maximum of her cares and labors and too often at this time the severest griefs assail. If she be single there is a species of spiritual awakening and the realization that youth is utterly past. In married women the disappointments which follow upon enthusiastic expectations become manifest, and in numberless ways strains are thrust upon the organism. It must be remembered that the greatest maturity of the powers, also, are evident at this time, and therefore she should be capable of meeting all exigencies. The whole question may be summed up in a few words: if a woman, married or single, will so order her life that she retains to the best of her ability her physical and mental vigor, and if she also sets her face sedulously toward looking upon the bright side of existence and ignores emotional impressions of a disagreeable character, she has nothing to fear as life moves steadily on the downward inclineand assimilated material. The life of woman leads her to become more impressionable and to watch over her menstrual days, think of them, make allowances for the exigencies which may arise at such times, and to expect various disturbances and discomforts. If her mind becomes fixed upon some one small ailment or other, especially connected with this function, there is almost an inevitable hyperconsciousness and a continuance or an exaggerated degree of attention which is practically hysterical even in the best of women. Such disturbances as do arise about the time of the menopause are largely due to a normal failure of the organism to