diving

diving,

the act of work or recreation in an underwater environment. The main health effects are related to the increased pressure to which the person is subjected as the ambient pressure generally increases by 1 atm (14.7 pounds per square inch) for each 33 feet of descent below the water surface. Conditions that warrant caution about diving include obesity, diabetes, alcoholism, epilepsy, drug abuse, and respiratory disorders, including allergic rhinitis. See also decompression sickness, diving reflex.

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diving

the act of submerging underwater; diving by fish and amphibians creates an obvious need for mechanisms that allow them to be submerged under water for long periods. Most mammalian and avian orders also have aquatic species that have a similar need. Diving reflexes operate as soon as nostrils are submerged and include oxygen conservation, respiratory arrest, intense peripheral vasoconstriction, bradycardia and compression of the chest with almost complete evacuation of the lungs.