Glucose Homeostasis During Short-term and Prolonged Exposure to High Altitudes

Abstract

Most of the literature related to high altitude medicine is devoted to the short-term effects of high-altitude exposure on human physiology. However, long-term effects of living at high altitudes may be more important in relation to human disease because more than 400 million people worldwide reside above 1500 m. Interestingly, individuals living at higher altitudes have a lower fasting glycemia and better glucose tolerance compared with those who live near sea level. There is also emerging evidence of the lower prevalence of both obesity and diabetes at higher altitudes. The mechanisms underlying improved glucose control at higher altitudes remain unclear. In this review, we present the most current evidence about glucose homeostasis in residents living above 1500 m and discuss possible mechanisms that could explain the lower fasting glycemia and lower prevalence of obesity and diabetes in this population. Understanding the mechanisms that regulate and maintain the lower fasting glycemia in individuals who live at higher altitudes could lead to new therapeutics for impaired glucose homeostasis.

Metabolic basis to Sherpa altitude adaptation

“…5C), who also showed faster clearance of glucose during an OGTT (P < 0.001; Fig. 5D) in agreement with previous reports (41). In Sherpas, however, there was no indication of altered glucose homeostasis.…”

Cardiometabolic risk factors in native populations living at high altitudes

“…Many studies have reported lower fasting glycaemia in clinically healthy residents living between 3000 and 4500 m, compared with residents living below 500 m. This difference has been reported in adults (26,39,43) and also in neonates (44). Lower fasting glycaemia in adults at high altitudes was shown in a large clinical study from a nationally representative sample in Peru (45).…”

Inverse association between altitude and obesity: A prevalence study among andean and low‐altitude adult individuals of Peru

“…Based on the definition of high altitude (≥1,500 m) and the frequency distribution of the number of individuals who reside within a given altitude band, altitude was grouped in four categories: 0‐499, 500‐1,499, 1,500‐2,999, and ≥3,000 m. For the latter category, the median of the altitude was 3,397 m (interquartile range: 3,245.0‐3,725.0 m). The district with the highest altitude surveyed by ENAHO was located at 4,660 m. Since moderate or vigorous physical activity for at least 150 min per week has been shown to result in a more sustained weight loss , we grouped the variable physical activity (total minutes per week of moderate and vigorous activity at work, home, and during recreation) in four categories: 0‐149, 150‐299, 300‐449, and ≥450 min.…”

“…Although acute suppression of appetite and weight loss in lowlanders exposed to high altitudes is well documented (37,38), the direct effect of prolonged altitude exposure on appetite remains unknown. Basal metabolic rate and sympathetic activation does not appear to be higher among highlanders as compared with lowlanders, even if normalized to fatfree mass (17). Since there is an inverse relationship between elevation and ambient temperature (39), cold-induced increased thermogenesis could explain the lower prevalence of obesity, including abdominal obesity, at higher altitudes.…”