The biological effects of high pressures: underlying principles

Physico-chemical principles set constraints on the response of biological systems to high-pressure gases and to pressure per se. They also indicate the mechanisms that may be involved. Classical thermodynamics, intermolecular forces and the theory of solutions and many other areas of physical chemistry have contributed to our understanding of the problems faced by divers breathing gases at high pressure, in particular the high pressure neurological syndrome, inert gas narcosis and decompression sickness. The value and the limitations of physico-chemical arguments when applied to the problems of underwater physiology are analysed.