Tibetans retained innate ability resistance to acute hypoxia after long period of residing at sea level.

Could the intrinsic characteristics of tolerance to hypoxia be retained in Tibetan high-altitude natives after they had migrated to a low altitude? To answer this question, we undertook a study of 33 healthy male adolescent Tibetans born and raised in a high plateau (3,700 m [12,140 ft] above sea level) who migrated to Shanghai (sea level) for 4 years. Ten age-matched healthy male Han adolescents born and raised in Shanghai were regarded as the control group. Acute hypoxia was induced in a hypobaric chamber for 2 h to simulate the 3,700 m altitude.

Exercise thermoregulation in Thai and Polish male subjects.

The aim of this study was to compare the efficiency of exercise thermoregulatory functions in Thai and Polish groups. Twelve Thai and 14 Polish healthy male students were included. An exercise test on a bicycle ergometer at 53% of the maximal work load was performed at ambient air temperature of 30 degrees C and relative humidity of 70%.

Reticuloendothelial phagocytic activity in high-altitude acclimatized rats.

Experiments were undertaken with rats to determine the effects of chronic exposure to a simulated high altitude of 5,000 m on phagocytic activity of the reticuloendothelial system (RES). Phagocytic index (K) was determined by measuring the rate of blood clearance of colloidal carbon given intravenously. K value of the chronically altitude exposed rats was found to be greater than that of the sea level control animals (p less than 0.

Hemodilution during standardized hemorrhage in high-altitude acclimatized rats.

Ten control rats and sixteen high-altitude acclimatized rats were bled at sea level into a reservoir which maintained arterial pressure at 35 mm Hg. As soon as the animals had spontaneously taken back 30% of the maximum bleeding volume, all the shed blood remaining in the reservoir was reinfused. Hemodilution was studied during the first half phase of hypotension starting from the point of initial blood withdrawal and ending at the point of maximum blood loss.

Standardized hemorrhagic shock in rats after acute and chronic exposure to high altitude.

Acute exposure to high altitude for 1 day in rats caused an increase in hematocrit (Hct) with no change in mean arterial blood pressure (mABP) from the non-altitude control, whereas after prolonged exposure to altitude (5-6 weeks) there were increases in both Hct and mABP. No changes in total plasma protein (TPP) and plasma osmolality (POsm) from control rats were observed in all altitude-exposed animals. The ability of the acutely and chronically altitude and non-altitude exposed rats to resist hemorrhage was studied.