This thesis is a compilation of 5 different projects. A brief summary for each project is presented below. A Comparison of a Bubble-Wrap Bag and a Mountain Rescue Casualty Bag In a Cold Windy Environment: Reports from Norwegian mountain rescue teams suggest that one layer of bubble-wrap (BW) around a casualty requiring evacuation is useful in preventing loss of body heat. The aim of this study was to compare a BW bag against a previously evaluated casualty bag (CB) currently in use by some Scottish mountain rescue teams. Factors Affecting a Climber's Ability to Ascend Mont Blanc: The aim of the study was to determine the factors affecting a climber's ability to ascend Mont Blanc (4807m) using a number of variables collected at the Gouter Hut (3817m) before and after an attempted ascent on the Mont Blanc summit. Performance at Altitude and Angiotensin Converting Enzyme Genotype: The 'insertion' (I) rather than 'deletion' (D) variant of the human Angiotensin Converting Enzyme (ACE) gene is associated with both lower tissue ACE activity and enhanced performance at high altitude. The aim of the study was to examine whether the onset of acute mountain sickness (AMS), and further performance on reaching the summit of Mont Blanc are influenced by the ACE I/D polymorphism. The Effect of ACE Genotype and Hypoxic Ventilatory Response On Arterial Oxygen Saturation and other Physiological Measurements During a Staged Ascent to 5000m: The aims of this study were to consider the role of the ACE genotype on daily SaO2, HR and AMS during gradual ascent to altitude (5000m). Furthermore, the speed of Hypoxic Ventilatory Response, measured during rest at sea level, was used to predict the daily physiological responses of SaO2, HR, and AMS, while any ACE genotype related differences on HVR were considered. ACE Genotype and Mount Everest: The angiotensin converting enzyme gene has been previously associated with elite mountaineering status. We sought such an advantage in a prospective study of those attempting the ascent of the highest mountain on earth, Mount Everest (8850m). There were no genotype differences in those who succeeded vs. those who failed, p=0.56. Although suggesting that ACE genotype may have little influence upon mountaineering success, these data may be misinterpreted by the use of supplementary oxygen (in all those summiting). Finally, it may be that ACE genotype influences success more when acclimatisation time has been limited. Further investigations are required.