Hypoxia, Safety and Performance
Pilot Tom de Dorlodot flying high in the Karakorum, with oxygen and logging pulse oximeter on his right arm.
What will the project study?
Initially, we plan to measure the baseline physiology of paraglider pilots in flight, including heart rate (HR), heart rate variability (HRV), respiratory rate (RR), body temperature and skin conductance, accelerometry (G force) and oxygen saturation (SpO2) through equipping pilots with cutting-edge telemetry. We have already completed some preliminary work at 7,450 meters with Red Bull Athlete Tom de Dorlodot in the Karakorum in July 2016.
We will use the data from our field studies to simulate these conditions with high fidelity in a safe environment to further explore aspects of hypobaric hypoxia and undertake tests of performance, including markers of cognition (decision making) and safety (reserve throw and collision avoidance).
What is Hypoxia?
Hypoxia is a reduction in oxygen levels, hypobaric hypoxia is a reduction in available oxygen due to lowered atmospheric pressure, for example from an increase in altitude.
Hypoxia underpins critical illness at sea level, altitude illness at height and performance and safety in the air. To date, studies into hypoxia in otherwise healthy individuals have been conducted in hypobaric chambers and high altitude mountaineers and trekkers. We believe we can do this better through paragliding.
What is Paragliding?
Paragliding is an air sport that has developed over the last 40 years into one of the most widely practiced forms of free flight. There are an estimated 127,000 active paraglider pilots worldwide.
Flights of over 100km across country are regularly made, using dynamic (soaring) lift and thermal updrafts, with the current open distance record standing at 514km. Paraglider pilots have flown from the summit of Everest, ascended in thermals to over 7,000m and gained as much as 4,526m of altitude in a single flight. Beyond recreational flying, paragliding has active and closely-contested cross-country and acrobatic competition scenes where increased safety and performance advantages are constantly sought.
What the advantages of paragliding for hypoxia research?
Unlike mountaineers, paragliders are exposed to hypoxia over acute timescales, climbing at 1-10 m.sec-1 in thermal updrafts and reaching heights above 8000m, without days of acclimatisation. Better still, paragliders do this with minimal physical input, sat suspended in a harness below the paraglider wing and able to wear instrumentation, removing the confounding effects of exercise. They are also completely exposed to ambient conditions (cold, wind, noise, G forces and hypobaric hypoxia), adding realism without the need for extreme physical fitness, and so opening the studies up to a wider range of subjects. Paragliding is cheaper and more environmentally friendly than research using hypobaric chambers or powered aircraft.
We believe that paragliding has the potential to be the most appropriate, inclusive, cost-effective and environmentally sound analogue with which to study a wide range of healthy volunteers in hypoxic environments.
What are the potential benefits of the research?
Oxygen has profoundly affected the distribution of life on earth. Lack of oxygen at altitude and in the deep sea has driven adaptions across the spectrum of ecology: from invertebrates living on hydrothermal vents to birds migrating across the high Himalayas. Hypobaric hypoxia, the diminishing levels of oxygen at altitude, means that one third of people who climb above 2500m for work, pilgrimages or travel (approximately 140 million people per year) may suffer symptoms of acute mountain sickness. Up to 5% will develop life-threatening high-altitude pulmonary oedema (HAPE) and high-altitude cerebral oedema (HACE).
Hypoxia underpins critical illness at sea-level: the outcomes of heart attacks, strokes, traumatic brain injury, acute asthma and pneumonia all depend on precise management of oxygen delivery. Understanding the pathophysiology of hypoxia is the key to developing novel intervention points and refining treatment pathways in critical care.
The setting in which paraglider pilots fly and in which accidents occur, is unique among mountain and air sports: the slow and demanding climbing of mountaineering, the protected flight of an enclosed sailplane, and the explosive decompression of a failing fighter plane do not replicate the experiences, risks, and challenges of paragliding. There is almost no literature directly relating to paragliding physiology; however, there is a great deal of relevant work that may translate from allied disciplines: aviation medicine; accident investigation; altitude and temperature physiology; avalanche science, as well as human factors.
Paragliding is cognitively demanding, for example: reading the landscape for thermal triggers and calculate glide angles, while remaining sufficiently spatially aware to pilot a craft though an invisible three-dimensional air mass, often containing other gliders in close proximity; in cold, hypoxic, ever-changing and sometimes intimidating conditions. Competition and acrobatic flying are more demanding still.
Paragliding has become much safer over time but remains a high-risk pursuit. Most accidents are secondary to errors of piloting or judgement, rather than equipment failure. When accidents do occur, the consequences are often severe or fatal and we hypothesise that hypoxia and environmental exposure play their part. Understanding the physiological demands on placed on pilots is therefore key to establishing systems to prevent injury or loss of life. These might include further training, awareness and control of cardiorespiratory variables, instrument warnings, descent, supplementary oxygen, anti-G drogue chutes or active warming garments.
The project will refine the use of novel telemetry and wearable technology in austere environments, informing future studies in other spheres of human and animal free flight.
Finally, the project brings together animal biology, altitude physiology, aviation and space medicine, biomechanics and biotelemetry researchers to conduct fundamental studies in a singularly demanding environment. We hope it will serve as a springboard for a variety exciting projects in the future.