Armored 
Medical Research Laboratory 
Fo?=*t Knox, Kentucky 
PROJECT NO. 1 - COLD 7/EATHER OPERATIONS 
Report On 
Sub-Project No, 1-1 - Test of the Adequacy and Range of Use of 
Winter Clothing. 
Sub-Project No, 1-18 - Study of the Methods for Selection of Men 
for Cold Weather Operations, 
Project No. 1-1, 1-18 
10 April 1944 ARMORED MEDICAL RESEARCH LABORATORY 
Fort Knox, Kentucky 
Project No. 1-1, 1-18 
727-1 SPMEA 
10 April 1944 
1. PROJECT: No, 1, Cold Weather Operations, Sub-Project No* 1-1, 
Test of the Adequacy and Range of Use of Winter Clothing; and Sub-Project 
Ho. 1-18, Study of the Methods for Selection of Men for Cold Weather 
Operations, 
a. Authority: Letter Commanding General, Headquarters Armored 
Force, Port Knox, Kentucky, File 400,112/6 GNOHD, dated September 24, 1942, 
bo Purpose: To study the differences in the responses of men to 
cold; and to attempt to identify the individual attributes - anatomic, phy- 
siologic and psychologic'- which may be responsible for variation in the 
perception of distressing symptoms resulting from exposure to cold. 
2, DISCUSSION: 
a. It is the general practice to evaluate the protection afforded 
by cold weather clothing in terms of skin temperatures, of insulation ex- 
pressed as "do" value, and of changes in the comfort status of the subjects 
Major emphasis in the evaluation of clpthing has been placed upon the length 
of time it has been possible for a subject to remain seated in the cold in 
reasonable comfort. 
m b. In laboratory studies, the loss of body heat or drop in temper- 
/ature of local areas in well-clothed healthy men has not been demonstrated 
*to be of sufficient magnitude to be harmful. Changes in the temperature of 
the toes, where the greatest changes take place, have but rarely been as- 
sociated with even suggestion of tissue injury. Moreover, changes in body 
temperature have never been large, nor have they appeared to bear a con- 
sistent relationship to the amount of clothing worn. It seems therefore 
that the clothing of the healthy man is properly evaluated on a comfort 
basis, using subjective responses as the criteria. For wounded and injured 
men on the other hand, the requirements with regard to thermal protection 
have yet to be ascertained. 
c. Conclusions with regard to comfort value of clothing however, 
have been drawn in terms of an "average” soldier, never identified, but 
tacitly assumed to exist. Yet it has become increasingly apparent that 
-there are major differences Among men in their relative capacities to remain 
comfortable in the cold. ACC'Ofdirigiy," this 'study was uhdef 
purpose of surveying the extent to which military personnel dressed in 
arctic clothing varies in its tendency to experience distressing symptoms 
upon inactive exposure to ambient temperatures of -10°F to -14°F* 
1 d. The conditions of test have been selected to impose the greatest 
stress on the subject* To this end, the subjects have been seated quietly in 
cold room, with no opportunity to gain any advantage from exercise in the 
form of increased heat production, peripheral arteriolar and capillary dila- 
tation both in muscle and skin, and heat produced by friction between the 
feet and footgear, or the psychological advantage of distraction, all of 
which can materially improve man's comfort statusc 
3o CONCLUSIONS: 
a. The variations in the sensory experiences of men exposed to 
cold are significant Men may be/dassified into three relative categories 
of response: resi\&ant, susceptible, and intermediate0 This is true for 
colored as well as for white troops <> 
b. The rectal and skin temperature changes of these men do not 
correspond well with their sensory experiences® 
c. No one attribute nor any group of attributes - anatomic, phy- 
siologic, or psychologic - has been identified which would make possible the 
prediction of an inactive individual's capacity to remain comfortable in the 
cold* 
4* RECOMMENDATIONS; 
No specific recommendations are madd. Attention is called to the 
need in clothing testing for proper pairing of subjects in accordance with 
their sensory reactions to cold® The need for further study of the stimuli 
which affect the sensory experience of cold is also indicated® 
Prepared by: 
Arthur Freedman, Captain, MC 
Steven M® Horvath, Captain, SnC 
APPROVED 
WILLARD MACHLE 
Colonel, Medical Corps 
Commanding 
4 Xncls, 
#1 - Appendix 1, Survey of Sensory Experience of Subjects Exposed to Cold 
#2 - Appendix 2, Comparison of Temperature Data on These Subjects with 
their Sensory Experience 
#3 - Appendix 3, Study of a Number of Attributes of the Subjects with a 
View to Identifying some which might be Related to Comfort in the 
Cold 
#4 - Charts, 1 thru 11 
2 APPENDIX 1 
SURVEY OF SENSORY EXPERIENCE OF SUBJECTS EXPOSED TO COLD. 
a, Discussion. 
The wide range of behavior characteristics toward cold among men 
should be taken into account in evaluating the protective value of cold 
weather clothing. Any assertion that a set of garments offers protection 
down to a certain temperature may be quite misleading without such consider- 
ation, It is perfectly proper to raise the question - "For which man - re- 
sistant or susceptible - is a given outfit protective?" 
Because a method of classifying subjects in terms of resistance 
to cold was believed to be fundamental to cold room procedures, a survey 
r sample of men was undertaken„ Seventy-five (75) men 
including 56 white and 19 colored, were examined in eight (8) groups of 
approximately ten (10) men each. All men were regular Fort Knox troops 
who had had at least several months army experience beyond their basic 
trainingo 
Bach group was tested for three (3) days, a new group arriving at 
the laboratory on successive Monday and Thursday mornings. All were ex- 
posed in the cold room for the same length of time, and at the same time 
of the day. Since the purpose of the test was primarily to observe differ- 
ences in relative resistance to cold, all subjects wore the same arctic 
clothing outfit, as carefully fitted as possible. When accurate fit was 
impossible, the subject was given a larger garment rather than a smaller 
one. By and large, the smaller men had somewhat oversize clothing, while 
the other men had garments of approximately their proper size. The garments 
worn were: 
Underwear, wool, 5G-50 
Trousers, fldld, pile 
Trousers, field, cotton, CD 
Jacket, field pile 
Parka, field, pile 
Parka, field, cotton, OD 
Socks, cushion sole, 1 pair 
Socks* ski, 2 pair 
Shoe, felt (Alcan) 
Mukluks with burlap insoles 
Mitten, wool, trigger finger 
Mitten, shell, trigger finger 
Emphasis was placed on an attempt to evaluate the degrees of comfort 
or discomfort experienced by men quietly seated for three (3) hours in an en- 
vironment of -10°F to On half the men of each group, for two (2) of 
the three (3) days of test, skin temperatures were measured at about fifteen 
(15) minute intervals, and on one man of each group continuous oxygen con- 
sumption data were collected for the entire three (3) hour period. 
1 b. Sensory reactions to cold. The sensations perceived by clothed 
subjects in the cold are as follows*: 
1. (a) The initial sensation of coolness. i.e., the change from 
the sensation of comfort—which might be called no sensation at all—to an 
awareness that coolness has supervened. This sensation is not distressing 
anywhere on the body<> It can be the more accurately reported inasmuch as 
it need not be quantitatedo Within the limits of accuracy demanded by the 
reporting procedure, no doubt exists as to the reliability of such data 
even though they be subjective. 
(b) The intensification of the sense of coolness, which is 
noted as the state of being chilly or cold. On the hands and feet, this 
situation is no more disagreeable than that of being cool. Dexterity and 
tactile functions are easily restored if lost. It is never the cause for 
tff(S',subjecTTb wishing he were elsewhere than where he is. However, on 
f other parts of the body, on the legs, thighs, seat, chest, back, and neck 
chilliness or coldness are distinctly unpleasanfTand tfTeir recognition*ih 
consciousness ssems to be very closely related in point of time with the 
onset of shivering. The distinction between coolness and chilliness re- 
quires a judgment concerning degree of intensity on the part of the subject. 
Inasmuch as this type of judgment is based on personal conditioning and on 
the special meaning of the words to the individual, it cannot be relied 
upon to have the same significance from time to time or from man to man. 
2. (a) Shivering is not a sensation of the same order as coldness 
The two may be confused and unless properly advised, a subject may state 
that he is cold when he means that he is shivering, and actually perceives 
little or no sensation of cold at such time. In other words, .shivering is 
response to cold exposure. It consists of repeated involuntary 
activity of small or"large groups of skeletal muscle fibers associated with 
pilomotor aflivity, a Tendency toward a general increase in jrauscle tone as 
opposed to relaxation, and an effort tq__s brink the body Into a”Tmaller area, 
as manifested, for example, by the head being pulled down and the shoulders 
brought up and forward. Since shivering, as a body response to a cold en- 
vironment, is usually involuntary, it can be regarded by consciousness with 
some degree of objectivity. It is true that some individuals by voluntarily 
relaxing their muscular tenseness, are able to discontinue shivering, but 
* In many reports, cold has been used indiscriminately to describe both 
body sensations and drop in body temperature. This perhaps derives from 
the supposition that the sensation of cold bears a more or less precise 
relationship to body temperature, to the extent that changes in the state 
of comfort are regarded as a protective device for the maintenance of the 
homeothermic state. Such thinking leads to tjtie inference that body temper- 
ature change constitutes a direct and complete measure of the comfort value 
of clothing. The limitations of this approach are evident from the data 
here presented. Accordingly, in the present discussion comfort sensations 
and body temperature changes are regarded as separate phenomena in the 
studies of cold weather clothing. The word cold is reserved to indicate 
changes in the state of comfort and cooling is used to describe changes in 
body temperature. 
2 they are rarely able to do this for more than twenty (20) minutes♦ Con- 
tinued for any length of time, shivering is a distressing experience, 
fatiguing, and distracting. Concentration is difficult, fine muscular con- 
trol is only one thought-dominates the consciousness—the 
desire for termination of shivering, preferably with external heat, but 
by means of vigorous if external heat is unavailableT^Shivering 
is a phenomenon5^?Feeting nearly all parts of the body except the hands and 
feet, although digital function may be interfered the 
arm. 
(b) The experience in the distal extremities, corresponding 
to shivering of the torso, is the sensation of stinging or pain—often 
appreciated only in the tips ,pf the fipgppp. or toes. The correspondence 
lies in the probability* that these, too, are not primary sense data, but 
are sensations of changes taking place within the body, secondary to the 
primary stimulus* Pain and stinging seem to be of a different order of 
sensation than coldness, rather than an increased intensity of it. They 
f interfere with functional dexterity, accurate muscle coordination, and 
psychological drive. The desire for escape from them frequently takes 
precedence over other obligations. The onset of stinging and pain in the 
digits can be more accurately reported than the increase of the intensity 
of cold sensations, as is the case with shivering of the torso. «JJLke 
shivering, when stinging or pain appear, the sensation of coldness disappears. 
The justification for regarding the origins of stinging 
and pain of the digits as physiologically similar rests on somewhat in- 
secure ground* They do not always appear in the same order, but it is un- 
common for stinging to be present without pain developing shortly after- 
ward* To indicate their relationship, in point of time, the following 
analysis of their occurrence in the toes of subjects who experienced these 
sensations during ninety-nine (99) man-exposures of 3 hours duration to 
temperatures of -10° to -14°F is presented below* (Neither pain nor sting- 
ing occurred in seventeen (1?) man-exposures.) 
Order of Occurrence in the Toes of Stinging and Pain 
Event No. Cases 
Pain without stinging at any time 40 
Pain appearing before stinging, both present 13 
Pain and stinging occurring simultaneously 6 
Stinging appearing before pain, both present 31 
Stinging without pain at any time 9 
Total 99 
3, The third order of sensation consists of further intensification 
of the experiences of shivering and pain. The order of events in the digits 
. is usually a gradual increase in severity of the pain, sometimes associated 
\ with stinging, until numbness supervenes. However, the numbness need not be 
persistent, and sensation may return again. The sensation of pain itself is 
3 not always progressive*, but may be regressive, and pain may be replaced by 
comfort. Shivering, of course, may also change in intensity. The apprecia- 
tion of the intensity of these sensations differs from time to time and 
from man to man. As such they are of documentary interest, but hardly use- 
ful for accurate reporting. 
From the foregoing, it is not to be inferred that the awareness 
of initial cooling and of pain or shivering always follow the same order, or 
bear constant time relationships to each other. It seems to be possible for 
a few resistant men to experience early a sensation of cold, but to have 
extremity pain or shivering either late or not at all„ Conversely, a few of 
the most susceptible men do not experience initial coldness as early as some 
less susceptible. In a similar manner, the development of the extremely in- 
tense symptoms of severe pain and numbness do not follow in the same order 
as the onset of either cooling or of pain or stinging in the extremitiese 
However, there is no question that these manifestations of distress are 
phenomena which affect only the more susceptible individuals. A few subjects 
experience intense symptoms soon after pain appears, while others although 
experiencing pain, do notj during the duration of a test, become aware of 
an augmentation in its intensity0 
On the basis of the most constant and precisely reportable of 
these sensations, the awareness of the onset of pain or stingingin the flin- 
gers and/or toes, and of the onset of shivering, fifty-six (56) of the white 
subjects may be compared. It was found possible to separate the subjects 
into three (3) groups, as resistant, susceptible, or intermediate reactors 
to cold. 
The basis for classification was as follows; Shivering, pain 
and/or stinging in the hands, and pain and/or stinging in the feet were 
considered the three (3) manifestations of marked discomfort for the three 
(3) areas, torso, hands and feet. The hands were considered separately from 
the feet because they appear to cool at very different rates. Since there 
were three (3) days of test for each subject, a total of nj.pe (9) afrfe of 
rggppnses were obtained for each man: three (T5 of the three (3) 
areas.' manifestations of discomfort aientioned appeared in six (6) 
of the nine (9) records before two (2) hours of exposure had elapsed, the 
subject was classed as susceptible, provided he showed no exceptional re- 
sistance in any one of the modalities on all three (3) days. For example, 
an individual whose hands and feet manifested the symptoms of pain and/or 
stinging in less than two (2) hours every day, but who did not shiver until 
late in any test period, or not at all, would have the requisite six (6) 
responses for classifying him as susceptible, yet because of his capacity 
to avoid shivering, he would not be so classed. He would be placed in the 
intermediate category instead, because in that one modality he is actually 
resistant. 
Subjects were classed as resistant if they experienced no dis- 
comfort whatever as above described for at least four (A) of the nine (9) 
possible responses, provided that of the remaining five (5), pain, stinging, 
or shivering were experienced in no more than two (2) in less than two (2) 
4 hours. For example, a subject would be classed as resistant if he experienced 
no pain or stinging in either his hands or feet at anv time, but shivered no 
more than two (2) of the three (3) days before two (2) hours had elapsed. The 
remainder of the subjects was designated as the intermediate group. Inspection 
of charts 1 and 2 makes this somewhat clearer* Time is indicated in quarter 
hour periods because it is believed that the data are no more precise than this; 
but significance can be attached to the finding that at one quarter hour inter- 
val pain is not perceived, while in the next it is. 
It will be noted that the resistant group is one in which by and 
large, the distressing effects of cold are not experienced within three (3) 
hours,. It appears possible for these subjects to remain placidly seated for 
an unknown time longer than three (3) hours with only minor discomfort. 
Contrasted with these, th§ susceptible subjects become miserable early in 
their exposures and become progressively worse with time. The classification 
is admittedly arbitrary. Recognition is given to the fact that men’s responses 
are not always consistent from day to day. 
, Charts 1 and 2 indicate the time of onset of the distressing 
symptoms that result from exposure to cold under the conditions of test, of 
the most resistant men and the most susceptible men of the group of fifty-six 
(56) white men tested, for all three (3) days. It will be noted that nineteen 
(19) of the fifty-six (56) men may be considered susceptible in that their 
distressing symptoms appeared in two (2) hours or less of exposure, and that 
in very rare instances was any of these subjects able to go the entire three 
(3) hours of the test period without the occurrence of one of these symptoms. 
By contrast, twelve (12) of the men may be called resistant to the extent 
that all of them tended to be free of these distressing effects of exposure 
for all or the greater part of the test period. Some of them experienced 
no pain or stinging in their hands or feet at any time, while others did 
not shiver at any time; and if such symptoms did appear in this group, they 
did so toward the end of the test period. V»;ith the classification of nineteen 
,(19) men as susceptible and twelve (12) men as resistant, there are left twenty- 
five (25) men who may be called intermediate. As would be expected, some of * 
these closely approach the characteristics of the resistant group while others 
approach the susceptible. Indeed, within all the groups, the range is fairly 
wide, from quite susceptible to only moderately so, and from quite resistant to 
a lesser degree of resistance. The frequency histogram is shown in Chart 3. 
In addition to the fifty-six (56) white men examined in the cold 
room nineteen (19) colored troops were examined in an exactly similar manner, 
wearing the same arctic outfits and exposed to cold room temperatures of the 
same level® 
Among this group, the spread of reaction patterns was in general 
the same as among the white men, in that there were resistant and susceptible 
as well as intermediate reactors. The impression was gained, however, that 
one of the colored subjects was more resistant while others were more ex- 
tremely susceptible than any of the white men tested. The resistant man had 
the facial characteristics and color of a fujLl^lo^e^jj^^^r""^e3TesT*period 
was shortened by about a half hour for the colored troops because the more 
5 au&oeptible individuals among them complained much more bitterly of their 
pain and Hsliivering than any of the white subjectse The resistant and sus- 
ceptible colored subjects are compared in Chart 
To indicate in another way the wide range of human behavior 
toward cold, a system of scoring resistance has been employed,, This was done 
by assigning arbitrary numerical values to symptom intensities, and from the 
total of these deriving an index number for each man's responsiveness to cold® 
The data for the extremities were computed separately from those of the torso, 
because inspection of the data suggested that the behavior of the two areas 
differed# No system of weighting could be found which seemed to combine the 
two in a manner that wsuld satisfy even the loosest standards® The calcula- 
tion is based on the number of minutes during which any particular sensation 
was experienced by a subject for all three (3) days. If, for example, in a 
three (3) hour sitting period a man cooled in 30 minutes, he would have 
symptoms for 150 minutes® The greater the number of minutes therefore, the 
lo¥/er the resistance in the scoring system. 
For the feet and hands it was recognized empirically that cool- 
ness, chilliness, or ooldness were not distressing as detailed above, and 
they were given a weight of 1* Stinging and/or pain were given a weight of 
20 The system of weighting and the calculation of the index for the extremi- 
ties follows: 
• Weighting Factor 
Number of minutes feet and/or hands cool, chilly or cold xl a a 
Number of minutes feet and/or hands stinging or mildly 
painful x2 - b 
Number of minutes feet and/or hancfe s tinging and/or 
paining severely x3 = c 
number of minutes feet and/or hands numb x4 r d 
a 1 b 4 c 4- d = xnciex number for extremities. 
100 
For the torso, it was decided that although the sensation of 
coolness, as distinct from comfort, is not in any sense distressing, that of 
chilliness or coldness anywhere about the trunk is distinctly unpleasant® 
These sensations were therefore weighted differently,, 
Factor 
9 
Number of minutes torso cool xl - a 
Number of minutes torso chilly or cold x2 = b 
Number of minutes of moderate shivering x3 - c 
Number of minutes of intense shivering x4 * d 
a 4 b f c 4 d - Index number for torso 
100 
6 On the basis of these indices, admittedly crude, some idea 
may be obtained of the spread of comfort experience In the cold, in a group 
of young men. Chart 5 gives their distribution for the extremities and for 
the torso respectively. It will be noted that quite a large number of men 
failed to have any appreciably uncomfortable symptoms about their torsos; 
this might be expected from the infrequency of shivering among the resistant 
men. For those who did have symptoms, their distribution follows somewhat 
the normal expectancy0 The lower the final comfort index score, the more 
resistant the man*. 
7 APPENDIX 2 
COMPARISON OF TEMPERATURE DATA WITH SENSORY EXPERIENCE. 
The simultaneously recorded temperature data on the same subjects vtfiose 
sensory experience has been studied, emphasizes the important point that 
rtotal temperature drop of either the surface or the interior of the body is 
,not tfie sensatipnaT "Tfils illustrated by the individual 
protocolsresistant ari<3 siS’ceptible subject, and by the average data of 
the entire group of resistant and susceptible men. 
The following are the protocols of two men, one resistant, the other 
susceptible. It is noted that they behaved quite differently in their re- 
lative degrees of comfort in the cold,distressing symptoms appearing much 
sooner in the susceptible man; but the subject who was subjectively the more 
susceptible actually had higher surface temperatures than the resistant man 
at the end of three (3) hours of exposure. Their rectal temperatures on the 
other hand were much alike. 
AWARENESS OF SHIVERING 
Name 
Time of 
Avg. Body 
Avgc Body 
Rectal Temp. 
Onset after 
Surface . 
Surface 
after 3 hrs. 
Exposure to 
Temp, at 
iemp. After 
of Exposure 
Cold (Hrs.) 
Time of 
Unset (,°C) 
3 hrs. Ex- 
posure (°C) 
(°C) 
Elliott / 
(Resistant) 1st test 2^ 
24c 5 
24»1 
•36.73 
2nd test > 3 
— 
25.1 
36.61 
Terry 
(Susceptible) 1st test l£ 
28*4 
26<>8 
36.50 
2nd test 1 
28,6 
25o4 
26.73 
AUR3NBSS OF STINGING OR PAIN IN TOSS 
Name 
Time of 
Onset After 
Exposure to 
Cold (Mrs.) 
Toe Temp, 
at Time 
. of 0?iset 
(°C) 
Toe Temp. 
After 3 
Hours Exposure 
(°C) 
Elliott « 
(Resistant) 1st test 
> 3 
— 
5o4 
2nd test 
2-3/4 
3.9 
2.6 
1 Terry 
(Susceptible) 1st test 1-3/4 9*0 ?„7 
2nd test 1-1/2 14.1 8*4 
The dissimilarity-of sensory experience in the cold between the re- 
sistant and. susceptible subjects is no better reflected in the average 
temperatures of the entire group of subjects than it is in the records of 
the two men just presented. Chart 6 shows the average rectal temperatures 
of the resistant, susceptible, and intermediate subjects for three (3) 
successive exposures in the cold room. The similarity in the temperatures 
is in striking contrast to the differences in the comfort of the men. 
•Chart 7 shows the average surface temperatures of the same groups for 
two (2) successive exposures. Again there is no relation between the 
temperatures and the differences in sensory experience* 
In Chart 8 the average temperatures of each of the several areas 
measured are presented for two (2) successive exposures in the cold. It is 
clear from these charts that the sensory perception of disagreeable symptoms ' 
of cold bears little relationship to body temperature after a standard period 
of exposure. 
It would be desirable to know whether there is any temperature of the 
toes at which pain is perceived by a majority of subjects exposed to the 
cold, or whether there is a time-temperature factor involved in the perception 
of toe pain. Chart 9 indicates that pain in the toes is f^rst appreciated by 
different men at ranginjf/Trom The median toe 
temperature at the onset STpeln was 7°G for the entire group and 50% were 
found to be within 5° and 9°C0 There appears, however, to be no significant 
difference' in the distribution for the three (3) groups. The time of onset 
of pain after the beginning of exposure to the cold is neither constant, nor 
does it correspond with the toe temperature at that time. Indeed seven (7) 
subjects were not aware of pain in their toes r,t any time despite the fact 
that at the end of three (3) hours of exposure their toe temperatures ranged 
from 2*4 to 10.4°G* 
Chart 10 presents the relationship between subjective perception of 
shivering and average body surface temperature.* It is apparent that sus- 
ceptible men shiver early in spite of the fact that the body surface tempera- 
ture has not dropped substantially. A number of subjects failed to become 
aware of shivering during their entire exposure period. 
* Average skin temperatures were computed using the following weighting 
system: Chest -%.30; hip - ,30; arm - .16; thigh - .18; and toe - ,06, 
2 APPENDIX 3 
STUDY OF ATTRIBUTES OF SUBJECTS WHICH MIGHT 3E RELATED TO COMFORT IN THE COLD 
One objective of the study was to identify those attributes of the 
subjects, other than change, which might be correlated with 
their degree of susceptibility to cold. Accordingly, a variety of obser- 
vations were made which were thought pertinent to the preselection of men 
for cold combat theaters as well as for cold room studies. Data were 
collected on all subjects, but the tabular analyses which follow are for 
the white subjects only. 
/The attributes examined were: 
1. Age 
2. Height 
3. Weight 
4. Weight/tteight 
5* Surface Area 
6. GI Shoe size 
7* Scores 
8. Body Build 
9. Color of Hair 
10. Depth of Skin Color 
11. History of Frostbite 
12. Tendency to Sunburn 
13. Home State 
14. Emotional Stability 
15. Tendency to sweat in the palmer, solar, and axillary 
areas 
16. Liking for cold expressed before cold room exposure 
17. Response to Cold Pressor Test and Digital Plethysmo- 
graphy 
18. Pain response upon immersion of foot in water at 5°C 
19o Average number of cigaretts smoked per day 
20. Sensitivity to pain of intradenial injection of 10$ 
NaCl solution 
21. Time of Onset of shivering when exposed nude in cold 
room at -10°F, 
In brief, it appears that no one of the attributes examined correlates 
well with the degree of susceptibility of a group of men to cold. This is 
not to say that older men may not be more susceptible than younger because 
of degenerative arterial changes, nor that some men may not respond poorly 
to cold because of psychological deficiencies, which in turn are reflected 
as vasomotor effects. However, no one attribute thus fj.r investigated seems 
to be applicable to groups of men, in a manner sufficiei tly consistent to 
make prediction of resistance or susceptibility possible, 
It does appear from the following tabular data, that, among the resistant 
subjects, certain characteristics are relatively uncor.na:>n. For example, only 
a small number of resistant men are emotionally unstable, while the suscep- 
tibles are about half stable and half unstable. It appears too that resis- 
tant subjects as a rule know in advance of their liking for cold. Only three 
(3) of the twelve (12) expressed a dislike for it, yet found themselves re- 
sistant. Further, only two (2) of twelve (12) resistant subjects reported 
1 a tendency to burn when exposed to the sun, while of the susceptibles, half 
reported a tendency to burn and half an inclination to tan. This does not 
mean that one skin had a higher or lower erythema threshold than another0 
The assertion by a subject that he burns when exposed to the sun means that 
he experiences discomfort as a consequence of his exposure. It is an evalua* 
tion of a degree of well being dependent in part on the degree of tissue in- 
jury, but also is dependent on the autonomic and psychological reactions 
to the tissue injury« Finally, among the resistant men, nine (9) were hypo- 
reactors to the cold pressor test while only three (3) were hyperreactors. 
The susceptible men were equally divided between the two types of responses. 
However, when each resistant and susceptible subject's particular charac- 
teristics were examined individually, it was found that there was no consis- 
tency with regard to this apparent pattern. An over-all tabular treatment 
indicates no correspondence between resistance to cold and these four attri- 
butes. described above; namely, tendency to sunburn, emotional stability, 
expressed dislike for* cold, and cold pressor reaction. The distributions 
of all the white subjects, according to their various attributes, are given 
in the tables that follow. 
2 DISTRIBUTION OF RESISTANT, SUSCEPTIBLE AND 
ALL SUBJECTS, ACCORDING TO: 
—. 
RESISTANT 
SUSCEPTIBLE 
ALL SUBJECTS 
General Characteristics: 
, 
Average age 
20 02 
20,5 
20.5 
Average height (in.) 
66.5 
67.4 
67 o 6 
Average weight (lbs.) 
14V. 6 
145 oB 
14«o« 
Weight per unit height 
2C24 
2.17 
2.19 
Surface area (sq, M.) 
lo77 
1.77 
1.79 
Average G. I. shoe size 
7.16 
7-89 
8.17 
Total no. subjects 
12 
19 
60 
Body Build: 
Very slender 
4 
4 
14 
Slender 
3 
10^ 
25 
Average 
3 
4 
15 
Stocky 
2 
1 
Total 
12 
19 
59 
Color of Hair: 
Dark 
4 
6 
17 
Medium Blond 
4 
3 
14 
Blond 
3 
7 
23 
Gray 
1 
1 
Red 
1 
1 
No record 
1 
1 
Total 
12 
19 
58 
Depth of Skin Color: 
Dark 
6 
6 
21 
Fair 
5 
11 
32 
Very Fair 
0 
1 
4 
No record 
1 
1 
2 
Total 
12 
19 
59 
Geographical Region of Origin: 
Northern States 
3 
3 
11 
Central States 
7 
13 
35 
Southern States 
1 
1 
7 
No record 
1 
2 
Jl 
Total 
. 12 
19 
56 
Areas Previously Frostbitten: 
Ear 
2 
3 
5 
Cheek 
1 
0 
2 
Nose 
0 
1 
3 
Heel 
1 
0 
3 
Toe 
0 
3 
6 
Finger 
1 
1 
_a. t 
j No. of Subjects Frostbitten 
4 
6 
16 
Total Subjects 
12 
19 
56 
3 In every case of frostbite, a .history could be obtained of a hole in a 
glove or shoe, of melted snow inside the ‘THoe^fiigfcixnd in 
// cases" of FacTST freeilrmT subjects impression that 
the frostbitten areas had a greater tendency to get cold on that account® 
A.G.CeT. Score Groups: 
resistant 
SUSCEPTIBLE 
ALL SUBJECTS 
I 
0 
1 
3 
II 
3 
0 
5 
III 
2 
6 
15 
IV 
3 
3 
14 
V 
1 
0 
1 
Total 
9 
10 
38 
4 DISTRIBUTION OF RESISTANT, SUSCEPTIBLE AND 
ALL SUBJECTS, ACCORDING TO ESTB&TiSS 
OF: 
* RESISTANT 
SUSCEPTIBLE 
ALL SUBJECTS 
Sweating Tendency of Palos, Soles, 
and Axillae when not Overheated: 
Little 
‘5 
6 
21 
Moderate 
7 
11 
35 
Profuse 
0 
1 
2 
No Record . 
0 
1 
1 
Total 
' 12 
19 
’ 59 
Tendency to Sunburn: 
Tan 
9 
9 
32 
Burn 
2 
10 
26 
No Record 
1 
0 
1 
Total 
’ 12 
‘ 19 
‘ 59 
Reaction to Cold: 
Do not dislike it 
9 
10 
35 
Do dislike it 
1 
_2 
22 
Total 
12 
19 
57 
This last query was made because it seemed reasonable that the best way 
to determine whether a man remains comfortable in the cold is to ask himc It 
turns out, however, that many men don’t know, either because they have never 
been exposed enough, or because they have been exposed too much while wearing 
too little or improper clothing0 Moreover, if a man has had one especially 
unpleasant experience, he tends to remember it to the exclusion of others 
that were less strikingo The group listed above as not disliking the cold 
actually reported either that they liked it, were accustomed to it, or were 
indifferento The group who did dislike it invariably said Just that0 
5 DISTRIBUTION OF RESISTANT, SUSCEPTIBLE AND 
ALL SUBJECTS ON THE BASIS OF SPECIFIC 
TESTS 
RESISTANT. 
SUSCEPTIBLE 
ALL SUBJECTS 
Cold Pressor - 1st Test; 
Hyper-reactors 
3 
9 
27 
Hypo-reactors 
9 
10 
22 
Total 
12 
19 
56 
All subjects reclined eight (8) to ten (10) minutes, after which control 
pressures were taken until two which checked were obtained. The hand was then 
immersed in ice water, and blood pressure readings were made at one-half (J) 
and one (l) minute thereafter. The higher readings were selected. Hyper- 
reactors were said to be those who had systolic pressure elevations of 20 ram, 
and diastolic of 15 mm above control levels. 
Cold Pressor - 2nd Test; 
Hyper-reactors 
2 
4 
10 
Hypo-reactors 
2 
2 
6 
Total 
4 
6 
16 
This was a repeat test on sixteen (16) of the subjects previously ex- 
amined. It differed from the first in that the subjects reclined for at 
least fifteen (15) minutes before the test was administered, and blood 
pressure readings were made at one (1) and two (2) minutes after the hand 
was immersed in ice water. 
Time Elapsing Before Perception of Pain Upon Immersing 
Distal Third of Foot in Water 
at 5UC 
Less than 30 sec. 
7 
, 9 
2A 
31 to 60 seCo 
2 
9 
22 
61 to 90 sec. 
1 
0 
2 
More than 90 sedc 
0 
1 
6 
No pain perceived 
2 
0 
2 
Total 
12 
19 
.56 
nAdaptationM Time to the Pain Resultant 
from Immersing; Distal Third of Foot in Water at 5°C 
Less than 60 Sec0 
0 
1 
6 
61 to 120 Sec. 
4 
5 
15 
121 to 180 Sec, 
3 
3 
10 
181 to 240 SeCo 
2 
6 
11 
240: to 300 Sec, 
0 
2 
6 * 
More than 300 Sec. 
.1 
2 
6 
Wo pain perceived , 
2 
0 
2 
Total 
~ 12 
19 
66 
6 These two tests were performed by having the subject lie prone on a 
couch, while dipping the distal third of his foot in constantly stirred water 
at 5°C. The subjects were instructed to ignore the sensation of cold, and to 
report only the onset, augmentation, diminution, and disappearance of the deep 
aching pain, which is a characteristic response to this type of stimulus» The 
time of the first, and the difference in time between the first and last of 
these are given in the tables0 
Time of Onset of Shivering Upon exposure 
Nude in the Cold Room at 
-10°F 
1st Exposure 
RESISTANT 
SUSCEPTIBLE 
ALL SUBJECT’S 
Less than 60 sece 
6 
7 
20 
61 to 120 sec. 
1 
4 
10 
121 to 180 sec. 
0 
3 
7 
More than 180 sec. 
3 
1 
7 
No Shivering 
2 
i 
12 
Total 
I 
2nd Exposure 
12 
19 
56 
Less than 60 Sec. 
5 
9 
25 
61 to 120 Sec. 
1 
3 
10 
121 to 180 Sec. 
0 
1 
1 
More than 180 Sec. 
1 
4 
6 
No Shivering 
i 
2 
ik 
Total 
12 
19 
56 
For this test, two subjects at a time were taken into the cold room nude 
on the afternoons of their first and third days at the laboratory, from one 
(Ij to two (2} hours after the noon raeal0 They stood on a paper covered wood 
platform raised approximately two inches off the concrete floor. The onset 
of shivering was recorded as the first evidence of involuntary muscle quiveringo 
OTHER OBSERVATIONS; 
A gross evaluation of the inclination toward neurotic behavior was made 
following interviews with the subjects, in which questions were asked concern- 
ing the occurrence of palpitation, dizziness, headache, digestive disturbance, 
specific fears, and reactions to various types of stress. Only one subject 
seemed to be patently abnormal with symptoms strongly suggestive of the effort 
syndrome. He turned out to be a susceptible subject, but not as intensely so 
as some others who were considered emotionally stable. The distribution of 
the men was as follows: 
Psychoneurotic Tendency: 
Stable 
9 
9 
34 
Uns table 
1 
10 
22 
Total 
12 
, 19 
36 
7 To check the observations in this aspect of the study, Captain IA, B. 
Jensen, and U/Sgt. Hotter, psychologists at the Armored School, were asked 
to examine sixteen (16) of the subjects in more detail0 They used for this 
purpose two self-rating questionnaires, and an electroderraal apparatus for 
measuring skin resistance of the palm. Their results are given as they 
submitted them. 
"1. Sixteen (16) subjects were examined for initial skin resistance 
and skin resistance after two minutes with an electro-galvanic skin re- 
sistance apparatuso They also filled out self-rating scales dealing with 
overconcern with health (tendency toward hypochondriasis) and overconcern 
with self (psychasthenic tendency). Scores on these techniques were corre- 
lated with ratings of ability to withstand cold. 
M2. Slight trends were indicated, showing the relationship between the 
measures and ability to withstand cold. The susceptible subjects showed a 
tendency towards lower initial skin resistance, greater concern with health, 
and a neurotic tendency. This tendency was shown in difference between 
means for the top eight as compared to the bottom eight, and in low corre- 
lations between rank order of rating of ability to withstand cold and rank 
order of score on the various psychological techniques. Neither correlations 
nor the difference between means could be established to be statistically 
reliable with the small numbers of subjects used. A correlation of 0.39 
between concern over health and initial onset of shivering was the highest 
obtained. These trends were more significant when the original overall 
rankings were used, based apparently upon an immediate impression, than 
with the final set of ranking submitted. 
"3* Results of this examination suggested that a relationship exists 
between the factors studied and the measures of resistance to cold used in 
computing the ratings made. In order to determine whether or not this ten- 
dency is statistically reliable, larger numbers of cases would have to be 
examined. 
"4. Scores for the sixteen (16) subjects are appended*" 
8  
Ohms 
Initial Skin 
Resistance 
Ohms 
Skin Resistance 
2 Uinutes 
Health 
Inventory 
Psychasthenic 
Inventors 
RESISTANT 
Elliott 
30,000 
43,000 
1 
4 
Rodriques 
25,000 
35,000 
3 
10 
Cantley 
15,000 
52,000 
3 
4 
Fisher 
20,000 
28,000 
13 
17 
INTERMEDIATE 
Johnson 
16,000 
20,000 
1 
3 
Contreras 
110,000 
125,000 
6 
10 
Turner 
80,000 
85,000 
0 
0 
Woods 
30,000 
50,000 
5 
6 
Wyley 
18,000 
36,000 
1 
0 
Kerns 
19,000 
25,000 
13 
28 
SUSCEPTIBLE 
Venture 
30,000 
48,000 
5 
9 
Kornack 
26,000 
50,000 
6 
a 
Hansen 
26,000 
24,000 
9 
9 
Clark 
15,000 
20,000 
12 
14 
Gleckler 
54,000 
70,000 
8 
8 
Mantice 
25,000 
36,000 
1 
3 
(In interpreting this table, the lower skin resistance implies a greater 
inclination toward neurotic behavior, while the higher scores on the 
health and psychastenic inventories imply a greater tendency toward 
neurotic behavior—Author*) 
9 In addition to the preceding, a number of subjects were given intracu- 
taneous injections of 0.1 cc of 10% NaCl solution, and the time of onset 
and duration of deep pain were measured. There were too few subjects for 
the data to be significant, but it did appear that the cold resistant in- 
dividuals perceived the pain later, and reported its disappearance earlier 
than the susceptibles. Some colored susceptible subjects were also given 
this test, and their responses were much like those of the susceptible white 
subjects. However, one of the resistant and two susceptible subjects per- 
ceived no pain whatever from the injections despite their being given in a 
manner identical to the others; this appears to vitiate the reliability of 
the testo 
Digital plethysmography was performed by Captain L. W, Eichna on six 
(6) of the subjects; two (2) resistant, one (!) intermediate, and three (3) 
susceptible. The stimuli were: pinching, deep breath, ice applied to the 
neck, mental problem, loud noise, and immersion of the forearm in ice water. 
Review of the tracings revealed poor correspondence to cold susceptibility 
in that the only normal reactor of the group was a subject classed as sus- 
ceptible to cold, while the twq (2) men classed as resistant to cold tended 
to be hyper-reactorSo 
The number of dgaretts smoked per day was found to be on the average 
14.3 for the resistant, 11.3 for the susceptible, and 11,3 for all the 
subjectso These figures were quite unimpressive, although before the in- 
quiry was made, it was thought not unlikely that the heavy smokers would 
tolerate the cold more poorly than the light smokers or the abstainers 
because of known effects of smoking on peripheral blood flow in some men. 
Finally, in order to determine whether the men whose feet are the least 
comfortable in the cold room tend to have lower toe temperatures in comfort- 
able ambient temperatures, the following procedure was carried out. About 
three-quarters of any hour after the noonday meal, each subject was seated 
on the laboratory floor, with shoes and socks removed, and the legs out- 
stretched, the bare heels resting on the floor. The floor temperature was 
about 71°F and the air temperature between 76° - ?B°F. After the men had 
been quietly seated for half an hour, the temperatures of the dorsal and 
ventral surfaces of both great toes were taken with a therraopile0 These 
four temperatures were averaged. The subjects were then listed in rank order 
with regard to the average degree of comfort of their feet in the cold room 
over the three days of exposure, and this order of rank was plotted against 
the average resting toe temperatures0 It is seen in Chart 11, that no 
correlation exists, except that the three most susceptible men do have low 
toe temperatures; in none of these was vascular disability suspected. 
10 CHART I 
TIME OF ONSET OF SUBJECTIVE SENSATIONS OF COLD 
RESISTANT SUBJECTS 
PAIN 
OR STINGING 
FEET 
PAIN 
OR STINGING 
HANDS 
SHIVERING 
DURATION OF EXPOSURE UNTIL ONSET OF STATED SENSATION, HOURS 
LINES EXTENDING THROUGH 3 HOURS INDICATE STATED 
SENSATION NOT OBSERVED DURING TEST EXPOSURE PERIOD 
EACH SUBJECT OBSERVED ON THREE SUCCESSIVE DAYS 
CHART I CHART 2 
TIME OF ONSET t)F SUBJECTIVE SENSATIONS OF COLD 
SUSCEPTIBLE SUBJECTS 
PAIN 
OR STINGING 
FEET 
PAIN 
OR STINGING 
'HANDS 
SHIVERING 
DURATION OF EXPOSURE UNTIL ONSET OF STATED SENSATION, HOURS 
CHART 2 CHART 3 
DISTRIBUTION OF FIFTY SIX (56) WHITE SUBJECTS AS 
RESISTANT, SUSCEPTIBLE, OR INTERMEDIATE 
REACTORS TO COLD 
NUMBER OF MEN 
INTERMEDIATE 
SUSCEPTIBLE 
RESISTANT 
CHART 3 CHART 4 
TIME OF ONSET OF SUBJECTIVE SENSATIONS OF COLD 
COLORED SUBJECTS ) 
RESISTANT 
SUSCEPTIBLE 
DURATION OF EXPOSURE UNTIL ONSET OF STATED SENSATION, HOURS 
LINES EXTENDING THROUGH 2 !/2 HOURS INDICATE STATED 
SENSATION NOT OBSERVED DURING TEST EXPOSURE PERIOD 
* EXTRA PROTECTION PROVIDED IN THE FORM OF FUR GLOVES 
EACH SUBJECT OBSERVED ON THREE SUCCESSIVE DAYS 
CHART 4 CHART 5 
DISTRIBUTION OF 80 MEN IN RELATION TO 
THEIR COMFORT INDICES 
LOW INDEX NUMBERS INDICATE GREATER RESISTANCE 
HANDS AND FEET 
NUMBER OF MEN 
COMFORT INDEX 
TORSO AND LIMBS 
NUMBER OF MEN 
COMFORT INDEX 
WHITE SUBJECTS 
COLORED SUBJECTS 
CHART 5 CHART 6 
AVERAGE RECTAL TEMPERATURES OF 56 MEN BEFORE 
AND AT END OF 3 HOUR EXPOSURE TO COLD (-10°TO -14 
RESISTANT 
(12 MEN) 
' SUSCEPTIBLE 
INTERMEDIATE 
(25 MEN) 
TEMPERATURE, F 
TEMPERATURE, 
BEFORE EXPOSURE TO COLD 
END OF EXPOSURE TO COLD 
CHART 6 CHART 7 
AVERAGE BODY SURFACE'TEMPERATURES OF 56 MEN 
BEFORE AND AT THE END OF 3 HOUR EXPOSURE TO COLD 
RESISTANT 
(12 MEN) 
SUSCEPTIBLE 
(19 MEN) 
INTERMEDIATE 
(25 MEN) 
U_ 
o 
u_T 
cr 
3 
or 
LU 
Q_ 
LU 
h- 
o 
o 
r* 
£ 
3 
£ 
(T 
LU 
CL 
LU 
I- 
BEFORE EXPOSURE TO COLD 
END OF EXPOSURE TO COLD 
CHART 7 TEMPERATURE, °F 
AVERAGE TEMPERATURES OF SEVERAL BODY AREAS OF 56 MEN BEFORE 
AND AT THE END OF 3 HOUR EXPOSURE TO COLD (-10° TO-14° F ) 
BEFORE EXPOSURE TO COLD 
END OF EXPOSURE TO COLD 
CHART 8 
R = RESISTANT 
S = SUSCEPTIBLE 
I r INTERMEDIATE 
TEMPERATURE, °C 
CHART 8 CHART 9 
RELATIONSHIP BETWEEN THE TIME OF ONSET OF STINGING 
OR PAIN IN THE TOES AND COINCIDENT TOE TEMPERATURE 
COLD ROOM TEMPERATURE -14 F 
TOE TEMPERATURE, F 
TOE TEMPERATURE, °C 
HOURS OF EXPOSURE 
O - RESISTANT SUBJECTS 
• -INTERMEDIATE SUBJECTS 
+ - SUSCEPTIBLE SUBJECTS 
CHART 9 CHART 10 
RELATIONSHIP BETWEEN THE TIME OF THE FIRST PERCEPTION OF 
SHIVERING AND COINCIDENT AVERAGE BODY SURFACE TEMPERATURE 
AVERAGE BODY SURFACE TEMPERATURE, °F 
AVERAGE BODY SURFACE TEMPERATURE, C 
HOURS OF EXPOSURE 
O - RESISTANT SUBJECTS 
• -INTERMEDIATE SUBJECTS 
-f -SUSCEPTIBLE SUBJECTS 
CHART 10 CHART II 
RELATIONSHIP BETWEEN TOE TEMPERATURE AT 76 F. AMBIENT 
AND SYMPTOM INTENSITY ON EXPOSURE TO COLD (-I0°T0-14°F) 
TOE TEMPERATURE,°F 
TOE TEMPERATURE,°C 
—RANK ORDER OF FOOT COMFORT 
(AVERAGE OF 3 EXPOSURES ) 
CHART II