Physical Fitness of Children Resident at High Altitude in Bolivia

Abstract

In 7-15-yr-old children living in La Paz (Bolivia, altitude 3,700 m) (HA):

1. Maximal oxgen consumption (V̇O₂max) varies from 35 to 45 ml · min^-1 · kg^-1 and maximal heart rate from 188 to 194 beats · min^-1. These values arc lower than those of their counterparts at low altitude (LA) by 10-20% and 10 - 15b · min^-1, respectively.

2. The anaerobic metabolism is not affected by chronic hypoxia if the nutritional conditions and pubertal development of HA and LA boys are the same. When related to percent of V̇O₂max, submaximal O₂ debts are similar at HA and LA. After supramaximal exercise, maximal O₂ debts (45.7 ± 2.7 vs 45.91 ± 3.8 ml · kg^-1) and blood lactate concentrations (7.6 ± 0.6 vs 6.5 ± 0.6 mmol · 1^-1) are also the same at HA and LA. No differences are observed between the 2 altitudes in ventilatory (60 vs 56% V̇O₂max) and lactate (60 vs 65% V̇O₂max) thresholds. The altitude of La Paz does not alter the anaerobic performance of a force-velocity test (from 6 to 10 W · kg^-1) between the ages of 7 to 15 years but reduces by 14-17% the mean anaerobic power developed during a 30-s Wingate test. This decrease could be linked to a lower participation of glycolysis and aerobic metabolism at HA during this test.

3. Poor socio-economic and nutritional conditions do not modify the aerobic performance of boys living in La Paz but lead to lower maximal anaerobic power (from -17% to -25%) when compared with HA boys from a high sodio-economic background.

4. Finally, the altitude of La Paz does not change the development of aerobic and anaerobic metabolisms during puberty.

Key words

Maximal oxygen consumption - anaerobic metabolism - malnutrition - puberty development