is the practice of going underwater, either with breathing apparatus (scuba diving
and surface supplied diving
) or by breath-holding.
Recreational diving is a popular activity (also called sports diving or subaquatics), and includes technical diving, recreational scuba diving, freediving, snuba, snorkeling and a range of competitive sports performed underwater.
Professional diving includes diving as part of one's occupation, and takes a range of diving activities to the underwater work site. Commercial diving, military diving, public safety diving and scientific diving are aspects of professional diving.
Freediving is a form of underwater diving that does not involve the use external breathing devices, but relies on a diver's ability to hold his or her breath until resurfacing. Activities include breath-hold spear fishing, freedive photography, apnea competitions, and to some degree, snorkeling.
The scope of this portal includes the technology supporting diving activities, the physiological and medical aspects of diving, the procedures of diving, underwater activities which are to some degree dependent on diving, economical and commercial aspects of diving, biographical information on notable divers, inventors and manufacturers of diving related equipment and researchers into aspects of diving,
Decompression chamber interior
Decompression sickness (DCS; also known as divers' disease, the bends or caisson disease) describes a condition arising from dissolved gases coming out of solution into bubbles inside the body on depressurisation. DCS most commonly refers to a specific type of underwater diving hazard but may be experienced in other depressurisation events such as caisson working, flying in unpressurised aircraft, and extra-vehicular activity from spacecraft.
Since bubbles can form in or migrate to any part of the body, DCS can produce many symptoms, and its effects may vary from joint pain and rashes to paralysis and death. Individual susceptibility can vary from day to day, and different individuals under the same conditions may be affected differently or not at all. The classification of types of DCS by its symptoms has evolved since its original description over a hundred years ago.
Although DCS is not a common event, its potential severity is such that much research has gone into preventing it, and underwater divers use dive tables or dive computers to set limits on their exposure to pressure and their ascent speed. Treatment is by hyperbaric oxygen therapy in a recompression chamber. If treated early, there is a significantly higher chance of successful recovery.
Hans Hass (born 23 January 1919) is a diving pioneer known mainly for his documentaries about sharks, his energon theory, and his commitment to the protection of the environment. He was born in Vienna, Austria.