The Science

 

Our Research

As human beings, we have adapted and learned to inhabit almost every land-based environment on earth and this adaptability is key to our success as a species. All species require nutrition to maintain the complex body chemistry necessary for survival. Measuring the energy of that complex body chemistry, usually termed metabolic energy, is the focus of our research where we look at the food we take in as fuel and the ways we utilise different components of our food (carbohydrate, fat and protein - called substrate utilisation) for life and activity.

Evolutionary changes have allowed us to respond to changes in our environment that occur over millennia, but we must use the scientific knowledge about our bodies to adapt our behaviour and diet to sudden changes, for example:

  • diseases and their treatments;

  • natural disasters (fire, flood, famine & accidents); and

  • exploratory travel on land, space and the deep oceans.

As we climb from sea level, the pressure of air above us (the atmospheric pressure) reduces, as does the pressure of oxygen in the air and, as a result, the amount of oxygen in our blood (hypoxia) also reduces. Diseases, particularly respiratory diseases, can also produce hypoxia and research carried out on healthy volunteers ascending 8,000m mountain peaks, particularly Everest, has given insights into the functioning of muscles(1,2) functioning of the heart(3), blood flow to the brain(4), treatment of lung disease, particularly for patients in intensive care units (ICUs)(5) and the pre-hospital treatment of emergencies(6,7)

 

Why do research in Antarctica?

The major physiological challenge high mountains present is hypoxia. Antarctica is the coldest and highest continent on earth and as such presents multiple and sustained challenges to those who choose to explore it:

  • altitude up to 4000m;

  • temperatures down to -50°C;

  • high levels of sustained physical activity for those exploring on foot/ski; and

  • nutritional intake limited by compromise between the body’s need for nutrition and the energy required to transport food, and fuel to heat it.

Understanding the response of the human body to these multiple challenges gives an insight into surviving sudden changes in our environment.

 

Our previous work and results

The focus of our previous work on measuring the metabolism of those undertaking polar travel(8-10,12) has been centred on making highly accurate measurements of human metabolism in specialist laboratory facilities before and after expeditions:

Our existing research has shown that in well, physically prepared individuals with appropriate nutrition(11), there are minimal long-term changes in the metabolism of those undertaking polar exploration(8-10,12). Understanding what is necessary to minimise changes is essential to not only support exploration but to provide new approaches to managing diseases and their treatments and supporting disaster relief.

 

The Global Polar Altitude Metabolic Research Registry (GPAMS)

The number of individuals undertaking expeditionary journeys in Antarctica is small and for confidence in the scientific findings, measurements from substantial numbers of participants are needed. GPAMS has been created to collate data on subjects undertaking expeditions in polar and high altitude regions, including those from our studies, to maximise the scientific impact.

 

INSPIRE 22

Scientific studies are carried out to a protocol that describes in detail not only who participates but also what data is collected, how it is collected and how it is analysed. To ensure the data and results from INSPIRE 22 can be added to that in the GPAMS database to increase the number of participants available for analysis, the core data collected in our previous studies will also be collected for participants in INSPIRE 22 using the same protocol.

There are up to 3 weeks delay between the end of expeditions and studies being performed at the specialist facilities in the UK. Participants undertaking Antarctic expeditions on foot and ski acclimatise to the altitude and cold as well as the pre-packaged food and the heavy workload pulling sledges weighing up to one and a half times their body weight! Similarly, at the end of the expedition, participants will de-acclimatise back to their normal environment, diet and activity. The time period over which this acclimatisation and de-acclimatisation occurs in Antarctic travel is unclear but that it does occur is well recognised.

For INSPIRE 22 we are adding metabolic measurements in Antarctica immediately prior to and after completion of the expedition to investigate the effects of acclimatisation and de-acclimatisation for the first time. In addition, indirect measurements of metabolism, including sweat and cortisol, will be obtained throughout the expedition from newly designed body-worn sensors. Antarctica is not only challenging for explorers, it is also challenging for electronic measurement systems – exposed to the environment at the South Pole, a normal mobile phone would be likely to stop working forever! Therefore, the instrumentation used in Antarctica for INSPIRE 22 will be specially designed to meet the challenges of the environment.

Participants will be monitored using wearable technology while in Antarctica. Unanswered research questions remain: what physiological or biochemical signal should be measured?; what is the physiological normal when people are working hard in remote environments? This collaborative endeavour aims to investigate the potential opportunities that wearable technology can offer to explore these questions. The future success of wearable technologies lies in establishing clinical confidence in the quality of the measured data and the accurate interpretation of those data in the context of the individual, the environment and activity being undertaken. In the near future, wearable physiological monitoring could improve point-of-care diagnostic accuracy, better protecting our people, optimising performance and inform critical medical and command decisions. The work in Antarctica will help get one step closer to this.

Other additional parts of the protocol for INSPIRE 22 will include a protocol for measuring weight loss and body composition throughout the expedition as these are used to determine the energy expended during the expedition(10), and laboratory-based measurement of the changes in metabolic energy and substrate utilisation of the participants in response to hypoxia and in response to a 10°C drop in temperature.  Before and after the temperature drop, thermal imaging (infra-red imaging) will be used to see if there are temperature changes in specific parts of the upper body which could explain changes in metabolic energy and substrate utilisation.   

📸 Images by Caudwell Xtreme

 

References

1. Edwards LM, Murray AJ, Tyler DJ, Kemp GJ, Holloway CJ, Robbins PA, Neubauer S, Levett D, Montgomery HE, Grocott MP, Clarke K. The effect of high-altitude on human skeletal muscle energetics: P-MRS results from the Caudwell Xtreme Everest expedition. PLoS One. 2010;5(e10681).

2. Levett DZ, Radford EJ, Menassa DA, Graber EF, Morash AJ, Hoppeler H, Clarke K, Martin DS, Ferguson-Smith AC, Montgomery HE,  Grocott MPW, Murray, AJ. Acclimatization of skeletal muscle mitochondria to high-altitude hypoxia during an ascent of Everest. J FASEB ’41. 2012;26:1431.

3. Holloway CJ, Montgomery HE, Murray AJ, Cochlin LE, Codreanu I, Hopwood N, Johnson AW, Rider OJ, Levett DZH, Tyler DJ, Francis JM, Neubauer S, Grocott MPW, Clarke K. Cardiac response to hypobaric hypoxia: persistent changes in cardiac mass, function, and energy metabolism after a trek to Mt. Everest Base Camp J FASEB ’96. 2011;25:792.

4. Wilson MH, Edsell MEG, Davagnanam I, Hirani SP, Martin DS, Levett DZH, Golay X, Strycharczuk L, Newman SP, Montgomery HE, Grocott MPW, Imray CHE. Cerebral artery dilatation maintains cerebral oxygenation at extreme altitude and in acute hypoxia an ultrasound and MRI study. J Cereb Blood Flow Metab. 2011;31(29):2019.

5. Siervo M, Riley HL, Fernandez B, Leckstrom CA, Martin DS, Mitchell K, Levett DZH, Montgomery HG, Mythen MG, Grocott MPW, Feelisch M. Effects of prolonged exposure to hypobaric hypoxia on oxidative stress, inflammation and gluco-insular regulation: the not-so-sweet price for good regulation. PlosOne. 2014;9(e94915):4.

6. Imray CH, Grocott MP, Wilson MH, Hughes A, Auerbach PS. Extreme, expedition and wilderness medicine. Lancet. 2015;386(10012):2520-2525.

7. Wilson MH, Habig K, Wright C, Hughes A, Davies G, Imray CHE. Pre-hospital emergency medicine. Lancet 2015;386(10012): 2526-2534

8. Hattersley J, Wilson AJ, Gifford R, Facer-Childs J, Stoten, O, Cobb R, Thake CD, Reynolds RM, Woods D, Imray C.  A Comparison of sustained strenuous activity in polar environments on men and women.  Scientific Reports, 2020;10:13912.

9. Hattersley J, Wilson AJ, Thake CD, Facer-Childs J, Stoten O, Imray C.  Metabolic rate and substrate utilisation resilience in men undertaking polar expeditionary travel PlosOne 2019; e0221176. doi: 10.1371/journal.pone.0221176

10. Hattersley J, Wilson AJ, Gifford RM, Cobb R, Thake CD, Reynolds RM, Woods DR, Imray CHE. Pre- to post-expedition changes in the energy usage of women undertaking sustained expeditionary polar travel J. Appl. Physiol. 2019; 126(3):681-690, 2019.

11. Taylor N, Gifford RM, Cobb R, Wardle SL, Jones S, Blackadder-Weinstein J, Hattersley J, Wilson A, Imray C, Greeves JP, Reynolds R, Woods DR. Experience from the selection and nutritional preparation for expedition Ice Maiden: the first successful all-female unassisted Antarctic traverse.  J R Army Medical Corps. 2019; doi:10.1136/jramc-2019-001175. 

12. Gifford R.M, O’Leary T, Cobb R, Blackadder-Weinstein J, Double R, Wardle S, Anderson RA, Thake CD, Hattersley J, Imray C, Wilson A, Greeves JP, Reynolds RM, Woods DR. Resilient reproductive and adrenal endocrine function in Expedition Ice Maiden: the first all-female, unassisted Antarctic team crossing. Med Sci Sports Exerc. 2019; 51(3): 556-567.