Developmental Effects Determine Submaximal Arterial Oxygen Saturation in Peruvian Quechua.

Area of Science:

• Physiology
• Altitude Medicine
• Human Adaptation

Background:

• High-altitude natives exhibit superior arterial oxygen saturation (Sao(2)) during exercise in hypoxic conditions compared to acclimatized individuals.
• Understanding the long-term effects of developmental exposure to high altitude on Sao(2) is crucial for comprehending human adaptation to hypoxic environments.

Purpose of the Study:

• To evaluate the impact of lifelong exposure to high altitude on arterial oxygen saturation (Sao(2)) during submaximal exercise in Peruvian Quechua.
• To compare Sao(2) levels between individuals raised at high altitude versus those raised at sea level, before and after a training period.

Main Methods:

• Two groups of Peruvian Quechua (born and raised at high altitude [BHA] and born and raised at sea-level [BSL]) were studied.
• Submaximal exercise testing was performed in normobaric hypoxia, measuring Sao(2), ventilation (VE), and oxygen consumption (Vo(2)).
• Statistical analysis using repeated-measures ANOVA controlled for VE/Vo(2) and sex.

Main Results:

• Individuals born and raised at high altitude (BHA) consistently maintained higher Sao(2) (%) compared to those born and raised at sea-level (BSL) at all exercise workloads, both before and after training (p=0.005 and p=0.017, respectively).
• Both groups demonstrated a significant decrease in Sao(2) (%) as exercise workload increased (p<0.001).
• No significant differences in resting Sao(2) levels were observed between the BHA and BSL groups.

Conclusions:

• Developmental exposure to high altitude significantly contributes to the maintenance of higher arterial oxygen saturation (Sao(2)) during submaximal exercise in hypoxic conditions.
• Lifelong altitude exposure, rather than simple acclimatization, appears to be a critical factor in optimizing oxygen saturation in high-altitude populations.
• These findings highlight the profound influence of early-life environmental factors on physiological adaptation to hypoxia.