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Anthropometric changes associated with high altitude acclimatization in females.

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Anthropometric Changes Associated with High
Altitude Acclimatization in Females
JOHN P. HANNON, J. L. SHIELDS AND CHARLES W. HARRIS
Physiology Division, U.S. Army Medical Research and Nutrition
Laboratory, Fitzsimons General Hospital, Denver, Colorado 80240
ABSTRACT
The anthropometric effects of prolonged high altitude exposure were
studied in eight college women who lived on the summit of Pikes Peak (14,100 f t . )
for 2.5 months. Acclimatization to altitude was associated with a decrease of skinfold thickness and a reduction in limb circumference, but little change in body
weight. It was concluded that these changes reflected a loss of subcutaneous fat during the period of altitude exposure. Altitude exposure did not produce any alterations
in trunk circumference at the umbilicus or buttocks, but it did cause an increase in
the inspiratory chest circumference at the axillary level and a reduction in expiratory chest Circumference at the subscapular level.
The first anthropometric study of high
altitude natives, the Aymara Indians of
Bolivia and Peru, was reported in 1870 by
Forbes. Only a few individuals were actually measured, yet Forbes described these
Indians reasonably correctly as being short
and robust, relatively long-bodied but shortlegged, never corpulent and possessing large
chests. This latter characteristic, although
based upon linear and circumference
measurements not volume measurements,
was concluded to be an altitude adaptation, “affording space for an immense development of the breathing organs.” Later,
x-ray measurements of the thorax by Keith
(’23) and pulmonary function measurements by Barcroft et al. (’23) and Hurtado
(’32) confirmed Forbes’ original descriptions and conclusions. In Europe, Loewy
and Marton (’34) found an elevated vital
capacity in children residing at the comparatively low altitude of Davos (5,240
ft.) while Rengger-Perlmann (’28) observed the same change in adults of this
locality. Loewy and Wittkower (’37) noted
that most high altitude residents and animals were smaller than the same species
at low elevations and felt that this size
difference, as well as a reduction in body
fat and muscle mass was ascribable to an
increased amount of physical work. Some
of the foregoing characteristics can be
seen when low altitude residents are
brought to high altitude. In this respect,
the thoracic enlargement has been extenAM. J.
PHYS.
ANTHBOP., 31: 77-84,
sively studied (Barcroft et al., ’23; Keith,
’23; Tenney et al., ’52; Verzar, ’45) and
evidence showing a loss of body fat has
been gradually accumulating (Hannon and
Chinn, ’66; Surks, Chinn and Matoush,
’66). Insofar as we can determine, there
are only two reports containing quantitative anthropometric data on women exposed to high altitude. One of these is
the above indicated article of Forbes’ which
includes extensive measurements on one
Aymara female. The other is Heber’s report (’21) of his experience in the Ladak
province of Kashmir, wherein he describes
a few casual chest measurements which
were obtained from one woman, first at
5,000 feet and later after three weeks’
exposure to an elevation of 11,500 feet.
He found that her chest circumference
had increased by 0.5 cm at the higher
elevation, but does not indicate whether
this was an inspiratory or expiratory volume. In this same article, Heber states
that his wife observed a two-inch increase
in her chest circumference after living in
Ladak for two years.
The present report contains anthropometric data collected from eight college
women who lived for 2.5 months at the
summit of Pikes Peak, Colorado.
METHODS
Eight University of Missouri female
students, without prior high altitude exposure, were selected on the basis of nor77
78
J. P. HANNON, J. L. SHIELDS AND C. W. HARRIS
ma1 medical history, physical examination,
hematocrit and hemoglobin levels, electrocardiogram, chest roentgenograms, and
exercise tolerance tests. In addition, they
were screened for past work experience,
physical fitness as determined on a bicycle
ergometer, as well as general appearance
and personality. These latter criteria were
pertinent to their employment at the tourist
concession on Pikes Peak, where they
would be working long hours and meeting
the public. Over a three month period,
prior to altitude exposure, the subjects
were required to engage in sports activities, intramural and otherwise, to raise
their level of physical activity to approximate that expected on Pikes Peak. After
completion of low altitude measurements
they were flown from Columbia, Missouri
(elevation 700 ft.) to Denver, Colorado
where they remained overnight. The next
morning, they were taken to the summit
of Pikes Peak (elevation 14,000 ft.) by
automobile, a trip requiring 2.5 hours.
For the following two and a half months,
the women lived and worked in the tourist
house atop the Peak except for one day
per week, their day off, when they descended to Colorado Springs (elevation
6,000 ft.) or surrounding mountain areas.
In all of our determinations, at least one
week had elapsed since their last trip to
lower elevations. Experimental measurements were made after an overnight fast
in Missouri one week prior to departure,
after an overnight stay in Denver and
after 1, 7, 30 and 65 days’ exposure on
Pikes Peak.
On the indicated days, body weights
were determined in the morning shortly
after arising, with the subjects in a fasting state. They wore shorts and lightweight shirts. The overall accuracy of the
weight measurements was f 10 gm. Skinfold thicknesses were determined with a
Lange anthropometric caliper placed parallel to the normal cleavage line in the
respective areas. A pressure of 10 g/mmz
was employed. Five of the anatomical locations described in the study of Skerlj
et al., ( ’ 5 3 ) were included in these skinfold measurements. These were : brachial,
halfway between the shoulder and elbow
over the right triceps brachii; subscapular,
approximately 3 cm below the inferior
angle of the right scapula; suprdiac,
midway between the lower margin of the
ribs and the iliac crest on the right side;
umbilical, approximately 3 cm to the right
of the umbilicus and thigh, over the right
rectus femoris midway between the ilium
and the knee. Body circumferences were
determined with a flexible, non-stretch
tape using bony landmarks to insure
uniformity of placement. Since most of
these anthropometric measures, particularly skinfold determinations, can vary
greatly with technique, the same investigator performed each measure throughout
the study.
The data were statistically evaluated
with Analyses of Variances and Critical
Differences at the 0.05 level of confidence
computed (Lindquist, ’56). The actual
magnitude of these Critical Differences are
shown in the various figures that follow.
RESULTS
Although it would appear (fig. 1 ) that
altitude exposure was associated with a
progressive and apparently linear loss of
body weight, the changes were small and
not statistically significant. In fact, four
of the subjects exhibited either no loss or an
actual gain of weight during the 65 days
they lived at Pikes Peak.
Skinfold thicknesses, as seen in table 1,
were obtained at five locations. In all of
these, except the suprailiac region, altitude
exposure was associated with a thickness
reduction ( P I 0.05) which averaged from
as little as 1 mm in the subscapular re-
BODY WEIGHT
J
56L
’
Y
D
’
0
10
20
30
mIvs RT
40
50
60
A\K!=d@a = l Y
Fig. 1 Body weight changes during altitude
acclimatization. Weight on the ordinate, is expressed in kilograms. The abbreviation “D” refers to Denver and “C. D.” to Critical Difference
at PL0.05.
79
ALTITUDE ANTHROPOMETRY
TABLE 1
Effect of altitude exposure on skinfold thicknesses o f women
-
Skinfold
Brachial
Subscapular
Suprailiac
Umbilical
Thigh
Days at Pikes Peak
n
7
13.2k2.64
13.4C2.61
11.3k0.91
11.0C1.22
10.122.44
12.0C3.37
13.01-3.19
12.422.57
16.33~2.19 13.21-2.62
--
Rn
10.923.08
9.7k1.41
9.4i2.51
12.2k1.52
12.4f2.66
.--
RS
11.421.71
10.121.42
9.2C2.60
11.542.16
12.943.14
Critical
difference
1.84
1.06
n.s.c.
1.75
1.96
Values indicate mean skinfold thicknesses, in mm, + standard deviations for eight subjects. Critical Difference indicates minimum difference between means -where P C 0.05, as computed from an Analysis of
Variance of the data (see Methods).
gion to almost 4 mm in the thigh region.
In some areas the reduction in skinfold
thickness was reflected in a similar reduction in body circumferences (fig. 2). In
the upper arm, for example, an average
loss of about 1.5 cm was recorded over
the course of the summer. The thigh, which
showed a large skinfold reduction, also
showed a large reduction ( 2 cm) in circumference. On a percentage basis, howBODY
H/
CIRCUMFERENCES
,
,
27
UPPER ARM
-5
25
]
C.D. = 1.04
24
UMBlLl CUS
71
70
BUTTOCKS
94
ever, both limbs exhibited similar losses in
circumferences, that is, about 6% over
the period of altitude exposure. Trunk
measurements at the level of the umbilicus and the buttocks failed to show any
statistically significant altitude effects, although there is a suggestion of an increase in umbilicus circumference during
the first week of exposure.
At the level of the thorax, two rather
interesting alterations in body circumference were observed (fig. 3). One of these
was an early and sustained increase in
axillary circumference measured during
maximum inspiration. With maximum expiration, chest circumference at this level
was unaffected by altitude exposure. An
opposite picture was obtained when the
measurements were made at the subscapular level. Here altitude exposure had no
effect on chest circumference during maximum inspiration but produced an abrupt
and sustained decrease in circumference
when measured during maximum expiration.
DISCUSSION
This study shows that some women
lose weight during altitude exposure,
others gain and still others are unaffected.
THIGH
If the data are averaged, a slight, but
34
statistically, insignificant reduction is ob33
served. Men, on the other hand, character’ -D
b Ib 2b $0 40 o;
6b ’
istically show a large weight loss when
DAYS AT PIKES PEAK
taken to high elevations. For example, if
we compare the average weight change
Fig. 2 Effects of altitude acclimatization on
the circumference of the upper leg, upper arm, in women with that described for males
and lower trunk. Circumferences, on the ordinate, by Consolazio et al. (’68) we see (fig. 4)
are expressed in centimeters. The abbreviation about a nine-fold greater loss in males
“ D refers t o Denver, “C. D.” t o Critical Difference at P 40.05, and “N. S.C.” to No Signifi- than in females over similar periods of
exposure. Thus, after one month men excant Change.
93
80
J. P. HANNON, J. L. SHIELDS AND
C.
W.HARRIS
hibit an average loss of 3,900 g, which is
a typical value, while women exhibit an
average loss of 440 g. The greater loss in
87r
AXILLARY MAX. 1 men can not be attributed to a greater
level of physical activity; if anything, they
] C.O. 1.32
were less active than the women since the
latter were required to work in the Concession atop the Peak. In both sexes, however, a concerted effort was made to match
as closely as possible the low and high
78
altitude activity levels. A greater degree
of anorexia in men may be responsible
78
for this sex difference, but unfortunately,
SUBSCAPULAR MAX.
it was not feasible for us to evaluate
I N S.C)
76
caloric balance directly in the present
75
study of women. It is to be noted, however,
that these women experienced less moun71
tain sickness than normally seen in males
SUBSCAPULAR M IN.
C.D.= 1.75
(Harris et d.,'66) which would favor
better appetites and hence a lower de68
crement in food intake.
67L
In this study of women we found no
0
0
10
20
30
40
50
60
evidence of dehydration as has been reDAYS AT PIKES PEAK
ported for Himalayan climbers (Pugh,
'64).
In small mammals, various estimates
Fig. 3 Effects of altitude acclimatization on
of
body
water content have shown hypoxic
chest circumferences during maximum inspiration and maximum expiration. Circumferences, exposure to be associated with marked
on the ordinate, are expressed in centimeters. dehydration. For instance, Swann et al.
The abbreviation "D" refers to Denver, "C. D
('42, '43) found insensible water loss to
to CriticaI Difference at P L 0.05 and "N. S. C." be increased 50 to 100% in rats exposed
to No Significant Change.
to a simulated altitude of 18,000 feet for
6 to 23 hours. Also in rats, Stickney reported ('46) significantly increased fecal,
BODY WEIGHT LOSS
(kilogmmr)
urine and insensible water loss while calculations by Picon-Reategui et al. ('53)
showed that dehydration could account for
94% of the body weight loss seen during
acute exposure to a simulated altitude of
15,000 feet. Lawless and Van Liere ('47)
studied the effects of hypoxia on tissue
water content and found a significant reduction in striated muscle and skin hydration at 18,000 feet, an observation which
is somewhat confused by the fact that
similar dehydration was not observed in
the animals exposed to 8,000 or 28,000
feet. In humans, many investigators have
attributed the weight losses observed in
mountain climbers or other sojourners to
I
dehydration. Pugh ('62), Balke ('59) and
t
2
3
4
5
10
20
X I 40 M 60
DAYS AT PIKES PEAK
Buskirk and Mendez ('67), for example,
Fig. 4 Comparative weight losses, in kilo- feel such dehydration is due to an ingrams, of men and women during high altitude creased respiratory water loss. There are
also reports (Consolazio et al., '68) of
exposure on Pikes Peak.
BODY CIRCUMFERENCES
Hf
,
-
I
"
"
1
,
4
I
ALTITUDE ANTHROPOMETRY
negative water balances of men during
acute exposure. But, unfortunately, there
is a paucity of actual data on the changes
in body water content, if any, which accompany high altitude exposure. Available
data fail to support the conclusion that
altitude exposure produces substantial dehydration, even during acute stages where
body weight declines rather markedly.
Nevison ('66) showed an increased turnover of body water in Himalayan climbers,
but he found no statistically significant
changes in the total body water content
as estimated by the DzO dilution technique.
Similar data have been reported by Buskirk and Mendez ('67). Recent measurements by Surks et al., ('66) and Hannon
and Chinn ('66) have shown relatively
normal levels of hydration in soldiers exposed for one to two weeks on Pikes Peak
as estimated by body densitometry and
antipyrine dilution. In both of the foregoing studies, measurement of body water
by DzO dilution was also attempted, but
the technique was found to be highly
unreliable, particularly during the first few
days of altitude exposure. In native populations of the Andes, Siri et al. ('54) PiconReategui ('61 ) and Picon-Reatgui and
coworkers ('61 ) employing, respectively,
antipyrine and tritiated water dilution
techniques observed little or no relationship between altitude and body water content. If anything, the data of Siri et al.
('54) indicate a slight increase in the
hydration of high altitude natives.
Altitude-induced changes in body fat
content have only been assessed indirectly
in humans. In the present study, the reductions in skinfold thickness suggest a
loss of subcutaneous lipid. Data on soldiers
reported by Surks et al. ('66), and Hannon and Chinn ('66), which were obtained
by body densitometry before and after
exposure on Pikes Peak, indicate a large
fat loss also occurs in males. On the basis
of D20 measurements, Gill and Pugh ('64)
reported reduced body fat levels in Himalayan climbers. Native residents of the
Andes, however, generally exhibit normal
or slightly reduced body fat levels (PiconReategui, '61; Siri et al., '54). Direct measurements have only been made in laboratory rodents, and these show a reduction
81
in body fat content under conditions of
simulated (Cullumbine, '52) and actual
(Chinn, '67) altitude exposure. Thus, it
would seem reasonable to conclude that
only the acute stages of altitude exposure
are associated with a loss of body fat, and
this loss probably accounts for most of the
body weight reduction.
The causes of these fat losses are not
known with certainty. In men the loss is
no doubt related to the anorexia which
accompanies acute exposure, and may be
enhanced by an increased rate of lipid
catabolism (Klain and Hannon, '68). In
women, as indicated above, anorexia does
not seem like a probable cause. It may be
related to their physical activity at high
altitude in spite of our attempts to regulate activity levels. Thus, similar decreases
in skinfold are seen during the training
of athletes (Thompson et al., '56).
The changes in thoracic circumference
seen in this study are somewhat difficult
to interpret. It should be pointed out that
while axillary maximum and subscapular
minimum values are significantly altered
after one week of exposure, these alterations are quite small in magnitude. They
do suggest the ability for enhanced thoracic volume displacement if maximum
inspiratory and expiratory reserves are
used. However, since these subjects exhibited a decrease in forced vital capacity
during altitude exposure (Shields et al.,
'68) the functional significance of the
changes in thoracic circumference are
nebulouse. Conceivably, hypoxia-induced
changes in tidal volume and minute volume, which have been observed in man at
various levels of oxygen consumption
(Grover, '63) could exert a training effect
on the musculo-skeletal aparatus of the
thorax, thus imparting greater capacity
for volume displacement. An enlargement
of the pectoral muscles might also be a
factor. Such alterations are indeed observed in physical training programs
(Morehouse and Miller, ' 5 3 ) , but it is
doubtful whether the alterations seen in
the present study could contribute materially to high altitude acclimatization,
at least in females. The direction of the
change, nevertheless, is toward the anatomical characteristics of high altitude na-
a2
J. P. HANNON, J. L. SHIELDS AND C. W.HARRTS
tive, and in this respect we should note
that the enlarged chest capacity of the
native is considered to be an acquired,
not a genetic, characteristic (Monge, '53).
ACKNOWLEDGMENTS
The authors would like to express their
appreciation to the Helen Stewart Co.,
particularly Mr. William Carle, manager
of the Pikes Peak Summit House who
agreed to employ the subjects of this study
for the entire course of the summer. The
data on weight losses of men exposed to
altitude on Pikes Peak were kindly provided by Mr. C. F. Consolazio of the Bioenergetics Division of this laboratory.
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