Diving and Hyperbaric Physiology - what have we learned?

Extreme Environmental Physiology Conference 2019

James Clark (King’s College London, UK)

The underwater environment poses a number of physical and physiological stresses on the body, not least of these is the effect of elevated ambient pressure which increases with depth. Hyperbaria is the underlying cause of a number of diving disorders mediated by gas saturation in the tissues including inert gas narcosis, oxygen toxicity and high-pressure neurological syndrome. In addition, inert (usually nitrogen) gas saturation has to be managed to avoid the clinical signs of decompression sickness. Traditionally, gas saturation during descent and desaturation on ascent has been the focus of considerable research and has undoubtedly led to many advances in our understanding of gases under pressure in the body, the development of safer decompression algorithms for divers, and a better understanding of bubble formation upon decompression including the use of technology to ameliorate decompression illness. Accordingly, this is the primary physiological challenge considered in recreational diving training manuals, text books. However. the recognition of other pathologies and physiological challenges through better understanding of immersion physiology and dysbaria has taught us valuable lessons in understanding, diagnosing and ultimately, assessing the risks associated with diving. This presentation will reflect on the history of diving research and take a look at current state and future perceptiveness in our understanding of the physiology of diving.