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Human adaptation to the high altitude environment

2017 Research Expedition - team photo

The Warwick Altitude Research Group (WARG), are a group of ten medical students with a special interest in high altitude physiology and medicine. Following the success of our inaugural research expedition to the summit of Mt. Jebel Toubkal last November, we undertook our second research expedition to the Capanna Margherita on the Monte Rosa massif in Italy.

The primary objective of the research was to investigate the physiological adaptations that occur during exposure to the hypoxic conditions of high altitude and its association with AMS. As altitude increases and oxygen levels drop, the body initiates several important adaptive mechanisms designed to compensate for the reduced supply of oxygen to tissues. However, these bodily adaptations can only compensate to a limited extent and several pathological processes can ensue. The most common of these is acute mountain sickness (AMS), with up to 80% of individuals exposed to high altitude reporting some degree of AMS. With greater numbers of people across the world travelling to high altitude destinations, it has become increasingly important to understand the effects and potential dangers of high-altitude exposure.

As a group we aimed to measure all basic vital signs in twenty participants during a graded ascent to 4554 meters over a period of six days whilst measuring their AMS symptoms using the Lake Louise Score. In addition to this, we carried out five individual research projects covering a diverse range of medical disciplines with the common goal of investigating human adaptation to the high altitude environment.

Our individual project aims were as follows:

1. Comparison of cardiac physiology between males and females at high altitude

24-hour ECG monitoring will be performed on seven male and seven female participants using Lifecard CF digital 3- lead Holter recorders. The recorded data will be used to detect any cardiac arrhythmias and identify any electrophysiological differences between males and females at high altitude

2. The renal response to acid-base imbalance at high altitude

The renal response to respiratory alkalosis will be investigated at several increments of altitude. Respiration rates and end-tidal CO2 volumes will be recorded using capnography. Participants will be asked to provide urine samples in sterile collection pots for the purposes of analysis. Urine osmolality and pH will be quantified using a digital pH and water analysis meter.

3. Changes to pupillary light reflexes and night vision at high altitude

Participants will have their eyes scanned at each altitude with a Neurolight Pupillometer after sitting for 10 minutes in darkness and 10 minutes in the light to assess how the pupils react to changes in light conditions during exposure to increasing levels of hypoxia.

4. Otologic function and intracranial pressure at high altitude

Pure tone audiometry will be used to assess hearing function at various increments of altitude, whilst a tympanic probe will be used to monitor any changes in intracranial pressure that may affect hearing.

5. Higher cognitive function at high altitude

Higher cognitive function will be assessed using the Delis-Kaplan Executive Function System, which consists of 9 subtests that generate 16 outcome scores. Participants will be asked to complete the tests at sea level and at high altitude.

2016 research expedition - team photo