Scuba Diving Physiology

Self-contained underwater breathing apparatus (SCUBA) diving was introduced to the world by Jacques-Yves Cousteau. In 1942, he, along with Emile Gagnan, developed the demand valve system that led to modern regulators. However, it was scientific research advanced by the work of Paul Bert and John Scott Haldane, from France and Scotland, respectively, that helped explain the effects of water pressure on the body and also defined safe limits for compressed air diving. Cousteau became famous by following these rules, surviving while many others before him died while diving. Much earlier in 1825, the "first workable, full-time SCUBA" was invented by an Englishman, William James. It incorporates a cylindrical belt around the diver's trunk that serves as an air reservoir at 450 psi. Air delivery to the diver was by turning a valve on and off as needed.