Physiological and metabolic responses to prolonged hypoxia and extreme cold: Preliminary data from the White Mars Antarctica winter expedition
Katie A O’Brien1*, Ross Pollock1, Mike Stroud2, Alex Kumar3, Robert J Lambert4, David A Green1, Lindsay M Edwards1, Stephen Harridge1
The Antarctic winter is amongst the most extreme environments on earth. Human adaptation to this envir- onment, where severe cold is coupled with moderate altitudes, is poorly understood. In this study, a number of physiological and metabolic measurements were made on a small group of trekkers before and after an attempted winter crossing of Antarctica (White Mars Expedition).
5 male subjects aged 28-54 yrs were assessed prior to and following a 24 week stay in Antarctica, including 14 weeks above 2,500 m. Measurements included
assessment of body fat and bone mineral density (DXA), cardiorespiratory responses to an incremental exercise test, lung and cardiovascular function as well as metabo- lomic analysis of serum using 1H-NMR spectroscopy.
Significant changes were found in the following para- meters pre to post expedition, identified using a paired Student t test (mean (SD), p < 0.05). There was an increase in % lean tissue (79+4 vs. 81+3%), a decrease in % fat tissue (21(4) vs. 19(3) %) and body fat mass (16(5) vs. 14(4) kg), although whole body weight did not change. Both spine bone mineral density (1.2(0.05) vs. 1.13(0.04) g.cm2) and FEV1:FVC (68(10) vs. 62(8)) were decreased. VO2max did not significantly change from the pre-expedition 42mL.kg.min, however an increase was observed pre to post expedition in the respiratory exchange ratio (RER) at each stage (10%) of the VO2max test (Figure 1A). Metabolomics analysis of serum samples revealed changes in two peaks within principal component 2: glucose and a fatty acid CH2 resonance (Figure 1B and 1C).
These results are suggestive of a number of physiologi- cal changes resulting from prolonged exposure to the Antarctic winter. In particular, we observed a change in metabolic signature involving changes to both glucose and fatty acid homeostasis with a shift towards increased reliance on carbohydrate metabolism during exercise.
This study has highlighted areas of interest for future investigations into the physiological responses to this unique environment.
Cite this article as: O’Brien et al.: Physiological and metabolic responses to prolonged hypoxia and extreme cold: Preliminary data from the White Mars Antarctica winter expedition. Extreme Physiology & Medicine 2015 4(Suppl 1):A121.