Hypobaric Hypoxia Causes Body Weight Reduction in Obese Subjects

Abstract

The reason for weight loss at high altitudes is largely unknown. To date, studies have been unable to differentiate between weight loss due to hypobaric hypoxia and that related to increased physical exercise. The aim of our study was to examine the effect of hypobaric hypoxia on body weight at high altitude in obese subjects. We investigated 20 male obese subjects (age 55.7 +/- 4.1 years, BMI 33.7 +/- 1.0 kg/m(2)). Body weight, waist circumference, basal metabolic rate (BMR), nutrition protocols, and objective activity parameters as well as metabolic and cardiovascular parameters, blood gas analysis, leptin, and ghrelin were determined at low altitude (LA) (Munich 530 m, D1), at the beginning and at the end of a 1-week stay at high altitude (2,650 m, D7 and D14) and 4 weeks after returning to LA (D42). Although daily pace counting remained stable at high altitude, at D14 and D42, participants weighed significantly less and had higher BMRs than at D1. Food intake was decreased at D7. Basal leptin levels increased significantly at high altitude despite the reduction in body weight. Diastolic blood pressure was significantly lower at D7, D14, and D42 compared to D1. This study shows that obese subjects lose weight at high altitudes. This may be due to a higher metabolic rate and reduced food intake. Interestingly, leptin levels rise in high altitude despite reduced body weight. Hypobaric hypoxia seems to play a major role, although the physiological mechanisms remain unclear. Weight loss at high altitudes was associated with clinically relevant improvements in diastolic blood pressure.

Hypoxic training: Clinical benefits on cardiometabolic risk factors

“…also found improvements in fat free mass and body composition in patients with obesity [9]. Although body weight reduction was not seen in healthy subjects [8] at altitude, patients with obesity [7,9] and metabolic conditions [6] saw reductions in body weight without significant loss of fat free mass.…”

“…Although improvements in SBP and DBP were not evident in healthy subjects [9,[18][19][20][22][23][24][25], patients diagnosed with hypertension resulted in 8-13mmHg [6,7,21] reduction in DBP and up to 26mmHg [21] reduction in SBP at altitudes of 1,285m-2,650m [6,7,21]. With patients with obesity (BMI ≥30kg/m 2 ), one week of exposure to altitude of 2650m resulted in DBP reduction of 13.9% [7], however ,no change in blood pressure were observed with non-hypertensive patients with obesity [9].…”

“…Intermittent hypoxic training used in conjunction with moderate exercise three times a week [8] was sufficient to bring about significant increase in lean body mass, however, in order for body weight reductions to occur continuous exposure of at least one week at minimum of 1,700m of altitude [6,7] is required. Exercise intensities used in conjunction with hypoxic that brought about positive outcomes in body composition and bodyweight ranged from 55-85% heart rate max.…”

“…A moderate altitude of at least 1,700m resulted in significant reduction in body weight in two studies [6,7] of between 1.5% and 3.3%. Of those two studies, one study [6] had control subjects performing the same training protocol at normoxic conditions, and body weight was not found to be significantly reduced compared to the control group.…”

Dietary factors, epigenetic modifications and obesity outcomes: Progresses and perspectives

“…For example, when studying the reasons for weight loss at high altitudes, higher metabolic rate and reduced food intake have been described, although the physiological mechanisms remain unclear (Lippl et al, 2010).…”