Biomedical subjects

L P Greksa

Publications and source records attributed to L P Greksa.

25 records · Page 2Linked to original sources

PubMedDate not supplied

Work performance of high-altitude Aymara males.

The sample for this study consisted of 28 Aymara males between the ages of 15 and 43 years. The subjects were rural high-altitude natives who were temporarily working as porters in La Paz, Bolivia (3700 m). Mean VO2max was 46 X 5 ml/kg/min. There was a significant negative relationship between VO2max and age in adult porters . However, there was also a significant positive relationship between maximal work output and age and a significant negative relationship between VO2 during submaximal exercise and age. Relative work intensity (VO2/VO2max) during submaximal exercise did not change significantly with age. Thus, even though VO2max decreased significantly with age, these data suggest that there may not be a substantial decrease with age in the adaptive status of these men. Minimal support was found for the hypothesis that chest size in Andean highlanders influences the effectiveness of the oxygen transport system.

Acclimatization↗

PubMedDate not supplied

Anthropometric survey of high-altitude Bolivian porters.

This paper presents the results of an anthropometric survey of 138 rural Aymaran high-altitude males who were working as porters in La Paz, Bolivia (3700 m). All subjects were measured for stature, weight, upper arm circumference, and triceps skinfolds. The body size and composition of the porters were then compared to an Aymaran rural population from the Bolivian highlands, and urban mestizo labourers from La Paz. The porters were smaller than the urban sample, but appeared to be generally representative of rural Aymaran natives with respect to body size and composition, and nutritional status. It is suggested that towards one extreme of nutritional variability, some degree of undernutrition may be indicated, which should be considered in future studies of adaptation to hypoxia among these Andean highlanders.

Acclimatization↗

PubMedDate not supplied

Effect of altitude on the physical growth of upper-class children of European ancestry.

The physical growth of 351 upper-socioeconomic-status children (9-20 years) of European ancestry residing in La Paz, Bolivia (altitude 3600 m) is described and compared with that of lowland children of similar background. The purpose is to evaluate the independent effect of continual exposure to atmospheric hypoxia during the period of growth and development on linear growth. The data presented here indicate that the effect of hypoxia on achieved stature ranges from minimal in males and none in females to a maximum of 3 cm in both sexes. The magnitude of this effect is relatively small compared to the potential effect of other factors which affect the growth of highland children.

Adolescent↗

PubMedDate not supplied

Lung function of young Aymara highlanders.

The patterns of development of FVC, FEV and %FEV are examined in 217 male and 195 female youths of Aymara ancestry residing in La Paz, Bolivia (altitude 3600 m). The data provide some evidence of an acceleration in the development of lung function relative to stature in Aymara children, beginning during early adolescence, and also indicate that there is a strong relationship between lung function and chest dimensions in Aymara children. Similar patterns have been observed among Quechua youth. However, despite the general similarity between Quechua and Aymara youths in the development of lung function, there are potentially important differences between them. In particular, the magnitude of the acceleration of lung volumes relative to stature among Aymara children appears to be considerably less than is exhibited by highland Quechua children. In addition, shorter Quechua boys have FVC values similar to those of shorter Aymara boys, despite having significantly larger chests, while taller Quechua boys have considerably larger FVC values than taller Aymara boys, without a corresponding increase in chest size relative to stature. Thus, although lung volumes and chest dimensions are closely related in both groups, the development of lung function to chest size of Quechua boys appears to be somewhat different from that of Aymara boys and, in particular, to be amplified during adolescence in response to factors other than simply an increase in chest size.

Adaptation, Physiological↗

PubMedDate not supplied

Age of menarche in Bolivian girls of European and Aymara ancestry.

Median age of menarche was determined in children of European and Aymara ancestry residing in La Paz, Bolivia (3600 m) and in children of European ancestry residing in Santa Cruz, Bolivia (400 m). Median age of menarche in European and Aymara highland natives was younger than reported by previous researchers, thus broadening the range of variation in age of menarche in high-altitude populations. Comparisons between La Paz and Santa Cruz European children suggested that growth and development at high altitudes results in a delay in median age of menarche of about 0.8 years.

Adolescent↗

PubMedDate not supplied

Growth and health status of preschool Karen highlanders.

The physical growth and health status of preschool (< 6 years) Karen highlanders belonging to the Pwo (212 males, 227 females) and Sgaw (107 males, 101 females) ethnic groups, and residing in northwest Thailand are described in the present report. The growth and health status of Thai tribal groups, including the Karen, is generally assumed to be substantially poorer than those of Thai lowlanders, who are primarily of Thai ancestry. However, the Karen highlanders in the present report fell within the range of variation in growth and health status found in lowland southeast Asians. Also, the growth and health status of Pwo preschool children tended to be significantly poorer than those of Sgaw children, despite the fact that both groups reside in isolated villages within the same ecozone and utilize similar food production techniques. The cause of these differences cannot be determined at the present time, but several potential factors are discussed.

Arm↗

PubMedDate not supplied

Maximal aerobic power in high-altitude runners.

Maximal aerobic power (VO2max) was assessed in seven male and one female middle- and long-distance recreational runners residing in La Paz, Bolivia (3600 m). All runners were born and raised at high altitudes (> 2500). Mean VO2max in the male runners was 60.8 ml/kg/min while VO2max in the female runner was 55.5 ml/kg/min. These values are higher than in any previously reported sample of either trained or untrained high-altitude natives. In addition, mean VO2max in the La Paz male runners and VO2max in the La Paz female runner were very similar to those found in comparable low-altitude samples of recreational athletes, suggesting that the cardiorespiratory systems of both normally active and highly active native Andean highlanders are capable of successfully responding to the stress of hypobaric hypoxia. This ability may have both developmental and genetic components.

Adolescent↗