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.
