Acclimation describes the physiological responses that are associated with the same physiological adaptations involved in in-country acclimatisation but as a result of techniques other than exposure to terrestrial altitude. Optimising acclimation is a contemporary research topic, as evidence based recommendations for efficacious acclimation, linked to appropriate in-country acclimatisation strategies, are not currently available. Acclimation and in-country acclimatisation are designed to decrease the probability of Acute Mountain Sickness, High Altitude Pulmonary Oedema and High Altitude Cerebral Oedema and improve performance and function at altitude.
Intermittent Hypoxic Exposure (IHE) has produced beneficial adaptations in haematological, respiratory (hypoxic ventilatory response, HVR) and exercise performance at simulated altitude. Given mountaineers’ response to altitude is a major determining factor to successful expeditions, the inclusion of IHE pre-expedition may provide beneficial physiological adaptations as well as potentially significantly decreasing acclimatisation time on the mountain. These potential benefits may also be advantageous for military personnel being deployed at short notice to high altitude. Current research is focused on finding the minimum stimulus to produce acclimation and optimise acclimatisation in country. Given the added stress stimulus associated with the physical demands of mountaineering and the interactive physiological demands of high altitude exposure and exercise, there is also a strong rationale for the inclusion of exercise within acclimation protocols. This justifies investigating combinations of IHE and exercise, as the addition of exercise increases the hypoxic load and the stimulus for ventilatory adaptation to altitude and is specific to preparing mountaineers or military personnel for high altitude exposure. Optimal IHE is therefore hypothesised to be facilitated by the addition of exercise, which is termed intermittent hypoxic training (IHT). Therefore, this study aims to establish whether IHT as an acclimation strategy is effective at reducing acute mountain sickness and enhancing physiological performance during the Dhaulagiri 2016 expedition.