Our breathing patterns will determine the optimal oxygen system for paragliding
SEARCH Projects’ Pilot Tom de Dorlodot, in flight over the Karakorum wearing the Free Flight Physiology Project Hexoskin and pulse oximeter.
When Tom and Horacio flew above 6,000 m wearing our monitoring equipment, their heart and respiratory rates were higher than the pilots flying at lower altitudes. This is no surprise: at extreme altitude, our bodies can increase circulating oxygen by breathing more then pumping the oxygenated blood around faster. However, we can breath more by either increasing the rate or depth of breathing. We found that Tom and Horacio tended to increase respiratory rate at extreme altitude, rather than depth.
Most paragliding oxygen systems are pulsed-dose, delivering a fixed volume of oxygen every time the pilot draws breath. Often, pulsed-dose systems can work better with higher respiratory rates, while continuous flow systems are more suited to slower, deeper breathing. However, if the faster breathing is also very shallow, then sometimes the pulsed oxygen doesn’t trigger well or reach the alveoli where it can be transferred into the blood. We are very mindful though that Tom and Horacio were only two individuals, so we would need to know if these findings were more generalised before drawing any firm conclusions on the best oxygen system for high altitude paragliding.
The jury is still out on the best oxygen system for pilots to use when flying at extreme altitudes. In particular, whether the system should be optimised for high respiratory rate or depth, or oxygen via the nose or mouth. It may be that current systems can be configured to better deliver oxygen to the parts of the lungs where it will be most efficiently used. (Please don’t let that put you off using oxygen though. This is still speculative, and we need to find out more.)
This is a summary of one of our key findings from Phase I of the Free Flight Physiology Project. For a full write up of our methods and results, please see our our Cross Country Magazine article or our scientific paper in High Altitude Medicine and Biology.