EFFECT OF CHRONIC HYPOXIA AND SOCIOECONOMIC-STATUS ON THE MAXIMAL OXYGEN-UPTAKE OF 10-YEAR-OLD TO 12-YEAR-OLD BOLIVIAN BOYS

The aim of this study was to analyze the effect of altitude and socioe conomic status on the maximal oxygen uptake (VO(2)max) of prepubertal Bolivian boys. The subjects were 143 prepubertal boys (10 to 11.5 year s old) living in La Paz (altitude 3600 m, n = 67) and Santa Cruz de la Sierra (altitude 420 m, n = 76). At high altitude, 23 boys were from a high socioeconomic status (HAHSES) and 44 from a low socioeconomic b ackground (HALSES). At low altitude, 29 boys were from a high socioeco nomic level (LAHSES) and 47 from a low socioeconomic background (LALSE S). Anthropometric characteristics were determined in order to assess the physical growth of the boys. The VO(2)max was determined from a pr ogressive maximal exercise (direct method). The subjects performed thi s test using the same cycle ergometer at both high and low altitudes. For the overall anthropometric parameters, there was no significant di fference between highland and lowland boys of the same socioeconomic s tatus. However, regardless of altitude, boys from a low socioeconomic background were 2 years behind those from a high socioeconomic backgro und. There was no significant difference for VO(2)max between boys fro m high and low socioeconomic backgrounds at HA (HAHSES: 37.2 +/- 5.6; HALSES: 38.9 +/- 6.4 ml . min(-1) . kg(-1) body weight) and at LA (LAH SES: 42.6 +/- 5.4; LALSES: 43.1 +/- 4.9 ml . min(-1) . kg(-1) body wei ght). The VO(2)max of highland boys was, on average, 11 % lower than t hat of lowland boys. It appears, therefore, that a difference in socio economic status has no effect on the VO(2)max (ml . min(-1) . kg(-1)) of prepubertal children at low altitude as well as the altitude of 360 0 m.