Fat Metabolism at Altitude
Increases in the energy requirements of individuals, and the subsequent breakdown of energy stores such as fat, have been shown to result from time spent at altitude amongst both healthy and obese individuals. Thus, leading to the suggestion hypoxic physiology has the ability to induce favourable changes in weight and fat mass amongst a human population.
It may therefore be suggested that exposure to hypoxic conditions, or altitude, has the potential to serve as both a preventative, and treatment method against the growing problem of obesity in today’s society.
The exact mechanisms behind such reports however are largely unknown and continue to be debated due to the large number of confounding factors present during field work and expeditions. Factors including changes in diet, increased physical exertion, extremes in weather conditions and lack of food availability can all play a role in weight loss at altitude.
Moreover differences in findings within the previous research highlight the complex nature of inquiry and the difficulty in investigating the effect of hypoxia in isolation on these factors. Nevertheless such findings of weight loss and changes in body composition have been attributed to other physiological factors including suppression in appetite (leading to a subsequent decrease in food intake and thus a negative imbalance in the energy equation) and biochemical alterations in fat and carbohydrate metabolism. Perhaps more importantly, previous research has also attributed a major part of these losses in weight to reductions in fat mass further supporting the potential for use in a health and clinical setting in which a loss of fat mass would be beneficial.
One of the physiological investigations being carried out during our time in Peru intends to address such an issue with weight loss, taste sensation, energy expenditure and fuel utilisation (the amount of fat, carbohydrate and protein used to fuel our bodies) all being measured at different stages of the trip. The investigation aims to answer the following research questions;
1. Does an eighteen day exposure to hypobaric hypoxia have a significant effect on an individual’s body weight?
2. Does exposure to hypobaric hypoxia alter the energy expenditure and fuel utilisation of healthy individuals?
3. Does energy expenditure and fuel utilisation alter throughout differing stages of acclimatisation to hypobaric hypoxia?
4. Is there a lasting effect of altitude exposure on energy expenditure upon return to sea level?
During our 18 day stay at altitude basal metabolic rate (BMR) (the number of calories required to fuel the body’s expenditure at rest) tests will be carried out at three differing stages of acclimatisation and be compared to the results of the same tests carried out both before and after our sojourn. Of particular interest is the question of whether or not individuals expend more energy whilst at altitude and if so if this is explained by the aforementioned confounding factors or if there is an underlying alteration in biochemical factors.
Integral to the accurate assessment of such parameters is the use of the Cortex MetaMax 3X which has been used throughout the investigation in both the laboratory and altitude based sessions. Pictures below.
As previously stated findings from this study may add to the current understanding of weight loss, energy expenditure, taste sensation and the biochemistry of fuel utilisation at altitude and may lead to the development of a weight loss technique through intermittent hypoxic exposures for an obese population. Furthermore if such an investigation can go a small way in informing the physiology behind weight loss at altitude as intended, there is potential for this information to aid those wishing to maintain weight during trekking in such conditions.