[Reprinted from THE CLIMATOLOGIST, March, 1892.] 
NERVO-VASCULAR DISTURBANCES IN UNACCLI- 
MATED PERSONS IN COLORADO. 
By J. T. ESKRIDGE, M.DJ 
DENVER, COLORADO. 
Nervous and vascular disturbances are the most prominent 
symptoms manifested by persons unpleasantly affected by high 
altitudes, but these are not the only symptoms, and are probably 
never the primary ones. Theoretically and practically, the lungs 
are the first to feel the effects of high altitudes, but unless the 
altitude be very great, the lungs very susceptible to changes in 
the density of the air, or the person indiscreet enough to take too 
much exercise on first going to high altitudes, he may let pass 
entirely unnoticed the slight disturbances in his breathing. Man 
in his normal condition easily adapts himself to any climate or 
altitude. He is almost the only animal who can live and thrive 
in the torrid zone with a temperature of 110° to 120° F., or in 
a frigid zone with a temperature from 60° to 80° below zero. 
He lives, works, and thrives thousands of feet below the earth's 
surface, or on the highest mountains, miles above sea-level, but 
to perform these feats a process of acclimatization is necessary. 
A study of the effects of extremely high altitudes on the unac- 
climated is exceedingly interesting. In 1887,1 reported a case of 
temporary amnesia and confusion of consciousness in a person who 
ascended to the top of Pike's Peak (elevation over 14,000 feet) on 
horseback. (See Journal of Nervous and Mental Disease, October, 
1887.) Last year (1890) I reported to this association an addi- 
tional case in which the legs were temporarily paralyzed in a man 
whilst crossing in a wagon one of the highest passes in the neigh- 
borhood of Leadville (elevation of the pass about 11,000 feet). 
I can now add a third case in the person of a tourist (male), who 
1 Read by title before the American Climatological Association in Wash- 
ington, D. C., September 22, 1891. 2 
ascended Pike's Peak during the present year on the cog-wheel 
railroad. The case was related to me by Dr. Chapin, of Phila- 
delphia, who made the ascent of the peak on the same train with 
the gentleman in question. When he reached the peak he felt 
perfectly comfortable, but on attempting to rise to his feet he 
found that he could not move his legs. 
In the present paper I shall only make this brief reference to 
the effects of extremely high altitudes on the unacclimated. I 
desire to discuss the effects of the altitudes of the usual resorts 
for invalids who seek Colorado for purposes of health. My 
remarks will not be limited to the invalid class, for I shall have 
something to say of the effects of altitude upon unacclimated 
persons advanced in life. 
An interesting paper might be written on the effects of a pro- 
longed residence in Colorado upon men and women, but especially 
upon the latter. It is a subject which I have been carefully study- 
ing for seven years, but, as the results of my observations differ 
widely from the views of some of the oldest and best-known physi- 
cians in Colorado, I desire still further to pursue my observations 
and studies in this direction, lest I have arrived at conclusions 
which are at variance with facts. 
In speaking of the influence of the climate of Colorado on the 
nervous and vascular systems of the unacclimated, I desire to be 
understood as referring to those who, on first visiting Colorado, 
take more or less active exercise, or live as actively as they had 
done at sea-level. By proper precautions the unacclimated in a 
vast majority of cases, be he an invalid or one in the enjoyment 
of sound health, can gradually accommodate himself to the effects 
of the climate, so as to experience little or no unpleasant effects in 
the process of acclimatization. Of this I desire to speak later. 
On going into a rarefied atmosphere the work of the lungs is 
immediately increased. The usual 11 tidal air" sufficient for the 
demands of the tissues at sea-level becomes inadequate, and the 
additional volume of air must be obtained by increased frequency 
of the respiratory act or by a larger quantity of air being inhaled 
during each inspiration. 
Theoretically it seems reasonable to expect that when the in- 
creased volume of air is obtained by increased frequency of respi- 3 
ration, the pulse is more frequent than when the respirations are 
slower and more prolonged. I have made a number of experi- 
mental observations on healthy and invalid persons to determine 
this question, but as yet I have not found a spirometer suitable 
to my purpose. The observations which I made without an in- 
strument to measure accurately the quantity of air inhaled at each 
inspiration, while they seem to point without much variation to 
increased frequency of the pulse under the condition above named, 
are yet not sufficiently accurate to be worthy of publication. 
I have had several opportunities of comparing the effects of 
exercise on my own person in Colorado with the effects following 
a similar amount of exercise at sea-level. Invariably the dis- 
turbances have been greater in the former than in the latter place. 
This accords with the clinical experience of nearly every physi- 
cian in Colorado, and needs no further comment here. 
It is difficult, if not impossible, to separate the circulatory from 
the nervous phenomena. If we note the disturbances of the 
heart's action as a type of the vascular systems, we shall find 
that they are largely of a nervous origin, or, if we analyze many 
of the nervous symptoms, especially headache, vertigo, etc., we 
shall see that they are directly due to vascular disturbances, 
although the latter have their origin in irritable nerve-centres. 
What part lessened atmospheric pressure plays in the production 
of many symptoms manifested by the unacclimated in Colorado, 
at altitudes varying from 5000 to 8000 feet, it is difficult to de- 
termine. That it exerts some influence is quite evident, but that 
the influence is almost inappreciable at an altitude of 5000 or 
6000 feet in producing unpleasant symptoms seems equally evident 
when we remember that by proper precautions the unacclimatcd 
whose breathing capacity is fair without having the atmospheric 
pressure modified, becomes accustomed to the altitude, and suffers 
but little inconvenience in the process as long as he gives his heart 
and lungs as little to do as possible. 
For all practical purposes, then, at altitudes varying from 
5000 to 8000 feet, the inconvenience of the unacclimated seems 
to have its origin in the increased respiratory activity, and this in 
turn leads to increased work of the heart, which by its over-work 
causes at first an active hyperemia and an irritability of the nerve- 4 
centres. Later the nerve-centres suffer from imperfect nutrition 
induced by a poor blood-supply which results from passive 
hyperemia. We have then the " irritable weakness" of the old 
pathologists. After the nerve-centres have become irritable, 
neither the respiratory act nor the heart's action is performed as 
regularly and methodically as in the normal condition; and, in 
consequence, various unpleasant symptoms are experienced by the 
unacclimated. Persons possessed of considerable vigor, and capa- 
ble of adapting themselves to great changes in their environments, 
go to high altitudes and live almost as they had done at sea-level, 
and find no appreciable inconvenience in so doing; but for those 
advanced in years and for those of feeble health the consequences 
are far different. 
Heart and Pulse.-I have observed the action of the heart and 
the condition of the pulse in a number who have experienced 
difficulty on going to Colorado. At first the heart's action is 
increased in frequency and force, and the pulse is increased in 
volume and tension; but soon the heart becomes irritable, its 
action is less effective, its beat is quite rapid, and, at times, irregu- 
lar or intermittent. At this stage the pulse loses its increased ten- 
sion and volume, and is usually small and weak. The superficial 
capillaries are commonly dilated, and if the heart be still further 
taxed, beginning cyanosis of the face and distal portions of the 
extremities renders apparent the inefficiency of the cardiac systole. 
Palpitation and oppression in breathing or various uncomfortable 
sensations over the precordium are quite common in those whose 
hearts have become irritable on going to Colorado. Some com- 
plain of a dyspnoeic or smothering sensation, and say that they 
feel as though they were unable to breathe sufficiently to relieve 
their distressed condition. 
An over-worked heart in a high altitude probably gives rise to 
the most distressing and alarming symptoms in those advanced in 
life, and especially to those whose hearts are fatty, or weak and 
flabby. In two such that I have seen, the first unpleasant symp- 
tom, beyond a little shortness of breath and a slight uncomfort- 
able feeling over the heart, was fainting, followed by cyanosis and 
prolonged unconsciousness with stertorous breathing. In one the 
unconscious condition lasted fifteen or twenty minutes, and in the 5 
other, several hours. Both were greatly prostrated after the at- 
tack, and did not regain their strength until removed to a low 
altitude. They were kept quiet, in a recumbent posture, and 
fed and stimulated for several weeks : but they seemed to lose 
strength, and finally had to be removed from Colorado in a re- 
cumbent posture, as a slight elevation of the head caused cardiac 
distress and a fainting feeling. Both rapidly recovered their 
strength on reaching a low altitude, where one well advanced in 
years is still living. The other is now residing in Colorado at 
an altitude of about 5000 feet, where, with proper precautions, 
the altitude seems to be borne quite well. 
Gastric and intestinal disorders are not infrequent in persons 
who suffer in the process of acclimatization. These are evidently 
of a twofold origin, nervous and vascular. 
In two persons, soon after their reaching Colorado, and on 
their taking an undue amount of exercise, I have known hemor- 
rhoids to be suddenly developed. In one case the constitutional 
disturbance was very severe. The patient, a lady, became hys- 
terical, had a chill lasting an hour or more, and this was followed 
by a rise of temperature, reaching 106° two hours after the chill. 
The temperature was 100° six hours later. A severe inflamma- 
tory attack of hemorrhoids followed. In this case there was no 
hepatic, gastric or intestinal trouble at the time to account for the 
development of the hemorrhoids. 
Hyperemia of the exposed mucous membranes is the ordi- 
nary experience of most persons who go to Colorado. Lessened 
atmospheric pressure may aid slightly in producing this, but the 
chief cause is the dryness of the atmosphere, except in those por- 
tions of the State in which considerable alkali is mixed with the 
dust. In the latter condition the hyperemia is followed by 
chronic inflammation and thickening of the exposed mucous sur- 
faces. Under such conditions, acclimatization does not protect, 
and these changes may be classed with the chronic effects of the 
climate, and need not be further considered here. 
Menstruation.-There is a prevalent opinion in Colorado that the 
climate modifies the menstrual flow in various ways, not only 
in the unacclimated, but also in those who have resided there 
a number of years. To what extent, I hope to be able to form 6 
some estimate, when I have gathered data for a paper on the 
chronic effects of the climate on the nervous and vascular systems. 
Many ladies seem to experience but little or no effect from the 
climate on their menstrual function on first going to Colorado, 
whilst in others the periods become irregular and the flow is in- 
creased. On this point I am not satisfied, as the number I have 
interrogated is too limited to enable me to draw conclusions, es- 
pecially in regard to a function that is so frequently perverted by 
causes other than climatal. 
In speaking of the nervous disturbances experienced in Colorado 
by the unacclimated who suffer from the effects of the climate, I 
shall try to refer to them as nearly in the order in which they arise 
as possible, although it must be remembered that this can be done 
only for the majority, as there are always exceptional persons who 
suffer differently from others. It is not an easy matter to know 
how much to attribute to climate. By some, every nervous symp- 
tom that is felt in Colorado is attributed to the evil effects of the 
climate, and these same persons lay down a dogmatic rule to the 
effect that every nervous affection is increased by going to Colo- 
rado. Of late, as the effects of the climate are being more care- 
fully and scientifically studied, we are learning to attribute some 
influence, especially on the nervous and hysterically inclined, to 
mental impression. Many persons who go to Colorado are fully 
convinced before they have been there twTenty-four hours that the 
climate will affect them unpleasantly, and that they will be unable 
to live there. They believe every exaggerated statement repeated 
by the credulous, and soon begin to experience the sensations that 
they have been led to think will be caused by a dry climate in a 
high altitude. Further, we have learned to contrast nervous affec- 
tions observed in the East with the same studied in Colorado, and 
some of us believe that we find but little if any difference in their 
course, except probably for the functional nervous disturbances 
which are, I think, slightly exaggerated by the climate of 
Colorado. 
Almost every person on first going to Colorado experiences a 
sensation of well-being and stimulation. The mind is active, and 
there is a tendency to indulge in day-dreaming or castle-building, 
rather than in a philosophical meditation. Thought after thought, 7 
in quick succession, rapidly flits through the mind, pleasant and 
entertaining for the time, but usually evanescent in character, 
and the aspirations and ambitious resolves, which are then formed, 
are short-lived, and rarely lead to permanent results. 
The motorial system is not unaffected, and the desire to exer- 
cise is great. If physical exercise be indiscriminately indulged 
in, the person soon becomes restless. To keep quiet then is diffi- 
cult and irksome, but to continue the exercise increases the ner- 
vous, restless feelings. The legs feel tired and heavy, and numb 
and tingling sensations, with pains in the joints, are often experi- 
enced. Sleeplessness follows, and this, combined with restless- 
ness, makes the night almost unendurable. I wish it to be under- 
stood in this connection that I am now speaking of the unacclimated 
who go to Colorado and live injudiciously. For the vast major- 
ity of persons, wffio seek Colorado for health or recreation and live 
as their changed environments demand, sleep is, as I have pointed 
out in another communication to this Association, easily ob- 
tained, sweet, prolonged, and refreshing. Headache is a common 
complaint of those who experience unpleasant symptoms in the 
climate, and more commonly follows than precedes sleeplessness. 
It is sometimes of a dull, heavy character, without definite loca- 
tion to any part of the head; at other times, it is frontal, but 
more commonly it is occipital, when it is often associated with a 
drawing sensation in the back of head and neck, and frequently 
with tenderness over the cervical spines. At this time the heart 
is irritable and tinnitus aurium is complained of. Following 
this train of nervous symptoms comes depression of spirits. 
The sufferer gets low-spirited and has " fits of the blues." In 
exceedingly nervous females it is not uncommon to hear out- 
bursts of hysterical manifestations. Some are troubled with 
fainting spells, dizziness, or even marked vertiginous sensations. 
Irritability and peevishness are common in those who have 
become excessively nervous on going to Colorado. Mental 
depression becomes so great in some as to lead to slight mental 
confusion. The mind may work all right for a while, but sus- 
tained mental effort is difficult and tiresome. I have not seen a 
case of insanity in which I have been able to attribute the cause 
solely to the effects of the climate. I have known a number of 8 
cases of insanity in which the violent outbreak has developed 
soon after going to Colorado, but in these the climate and scenery 
of the State had been sought simply for the sake of change and 
diversion, and the subject had been kept going from place to place, 
excited and over-worked, and in some cases sufficient sleep had 
not been obtained, nor the proper amount and quantity of food 
taken. 
Time for Acclimatization.-It is impossible to say how long a 
time is required for a given person to become acclimated. Many 
persons of vigorous health and constitution, with good lungs and 
a normally acting strong heart, seem to adapt themselves to their 
new atmospheric conditions almost immediately after reaching 
Colorado, and never experience any perceptible difficulty, al- 
though they indulge in active exercise and various other indiscre- 
tions regardless of possible effects. Others, less favored by nature, 
experience slight inconveniences on first taking active exercise, 
but on further persisting they cease to be troubled, and live as 
comfortably as they had done at sea-level. 
For all persons suffering from pulmonary disease, heart affec- 
tions, organic or functional, or from irritable and excitable ner- 
vous systems, the process of acclimatization is of the first 
importance, and seems to be but little understood, or, if under- 
stood, not heeded by the majority of physicians living at low 
altitudes. For each individual belonging to any or all of the 
three classes above mentioned, specific rules must be laid down 
by his physician in Colorado, and these rules can be only safely 
varied from time to time, as the favorable progress of the case 
may indicate. Time, per se, seems to play an insignificant part 
in acclimatization in these cases. It is the effect of the climate 
on the invalid, and not the time spent in Colorado, that enables 
the prudent physician to judge as to what his patient may or may 
not do. 
Some persons never become accustomed to the climate of 
Colorado, and although they may spend years there, are never 
able to live as they were wont to do at sea-level. For such, 
eternal watchfulness and care are the price of health and comfort 
there. 9 
How Persons Should Live During the Progress of Acclimatiza- 
tion in Colorado.-It is on account of the great importance of this 
part of my subject that I have endeavored to write on the nervo- 
vascular disturbances arising in the unacclimated in Colorado. 
For persons advanced in years, and for nearly all invalids, there 
is but one rule-keep comparatively quiet at first, and, when 
moderate exercise is begun, always stop short of the point of 
decided fatigue. I have not treated chest troubles since I went 
to Colorado, but, being a consumptive myself, I have taken a 
keen interest in a number who have gone there for pulmonary 
disease, and have tried to watch and profit by the causes that 
have seemed to determine their success or failure in regaining 
their health. Of the suitable cases of pulmonary consumption 
that have sought Colorado, I do not think I am exaggerating when 
I say that untimely and over-exercise have killed more persons 
than the progress of the disease. Both clinically and experi- 
mentally it is quite positively determined that a comparatively 
quiet life is the one most conducive to the health and welfare of 
the consumptive on first going to Colorado. For the consump- 
tive there are many reasons why exercise should be limited at 
first, and subsequently indulged in only as is thought safe by 
his physician. 
For persons of irritable nervous temperament, and for those 
suffering from weak or irritable hearts, a quiet life is by far the 
best on first going to Colorado. Persons, the muscular tissue of 
whose hearts is beginning to degenerate, should not go to Colo- 
rado or any other place with an altitude many thousand feet above 
sea-level. In all cases, no matter what the ailment may be for 
which a high altitude is sought as a health resort, it is better and 
safer for the patient to follow the directions of the local physi- 
cians than to try to take regular and systematic exercise, such 
as horseback riding, etc., not infrequently prescribed by their 
medical adviser who lives thousands of miles distant. It has 
been my lot to meet in Colorado loyal patients whose lives 
have been sacrificed by over-exercise in theii' attempts to take as 
much exercise as they had been requested to do by their physi- 
cians before they left home. The advice, often given by physi- 
cians, unacquainted with the climate of Colorado, on sending 10 
patients there, is: " Go to Colorado; live in the open air as 
much as possible; live on horseback all day long; herd sheep 
or drive (punch) cattle." The first part of this advice-"live in 
the open air as much as possible"-is excellent, but the remainder 
is simply murderous for nine out of every ten consumptive pa- 
tients who go to Colorado. 
In this paper I have endeavored to enumerate most of the 
nervous and vascular disturbances from which many invalids, 
who seek Colorado as a health-resort, and over-exercise on first 
going there, will suffer. I might add to the vascular disturb- 
ances, pulmonary hemorrhage, only, however, to be feared when 
exercise is considerable. On the other hand, for nine out of 
every ten invalids who go to Colorado and live as quietly as 
their cases demand, the process of acclimatization will be easy 
and unattended by any serious inconvenience. The other one- 
tenth, either on account of excessive nervousness, irritable or 
weak heart, or some other unavoidable cause, will experience 
some difficulty on first going there, no matter how quietly they 
live, but the disturbance is incomparably less by living a quiet 
life. Of course, in this estimate, we must exclude certain cases 
of far-advanced consumption with little breathing room, which 
should never go to a high altitude. Despite every effort to the 
contrary, there are a few nervous and consumptive patients who 
can never live comfortably in a high altitude. I suspect that in 
these cases the heart is at fault. Some persons go to Colorado, 
and while living a comparatively quiet life, are so uncomfortable 
as to have to seek a lower altitude, but in a few months return 
and live there without much inconvenience. 
I have known persons, for whom a lower altitude was out of 
the question, become so nervous and miserable in Colorado that 
their lives were a burden to themselves and friends, go to bed 
and live absolutely quiet for a few weeks, then become less 
nervous and be able to live there in comfort and take a mode- 
rate amount of exercise. In my opinion, the best management 
for all persons who become nervous, irritable, sleepless, etc., in 
Colorado on account of the climate, is a residence at a low alti- 
tude for a few months. We must remember that many persons 
become exceedingly nervous at sea-level, so that a great many 11 
cases of nervousness arise in Colorado with which the climate of 
itself has little or nothing to do. Some cases of nervousness 
arising at sea-level are benefited by going to Colorado, provided 
exercise be avoided at first. 
Most cases of pure nervousness arising in Colorado are more 
or less benefited on seeking a lower altitude. Published the 15th of each Month. 
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