MSD Manual

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Overview of Diving Injuries


Richard E. Moon

, MD, Duke University Medical Center

Last full review/revision Aug 2019| Content last modified Aug 2019
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NOTE: This is the Consumer Version. DOCTORS: Click here for the Professional Version
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People who engage in deep-sea or scuba diving are at risk of a number of injuries, most of which are caused by changes in pressure. These disorders also can affect people who work in underwater tunnels or caissons (watertight enclosures used for construction work). Such structures contain air under high pressure to keep out water.

Underwater pressure

High pressure under water is caused by the weight of the water above, just as barometric (atmospheric) pressure on land is caused by the weight of the air above. In diving, underwater pressure is often expressed in units of depth (feet or meters) or atmospheres absolute. Pressure in atmospheres absolute includes the weight of the water, which at about 33 feet (10 meters) is 1 atmosphere (14.7 pounds per square inch [1.03 kilograms per square centimeter]), plus the atmospheric pressure at the surface, which is 1 atmosphere. So a diver at a depth of 33 feet is exposed to a total pressure of 2 atmospheres absolute, or twice the atmospheric pressure at the surface. With each additional 33 feet of depth, the pressure increases by 1 atmosphere.

Pressure-related diving disorders can result from

Either process can cause bubbles in arteries to block blood flow to organs (arterial gas embolism). Gases such as oxygen and nitrogen can also cause disorders (oxygen toxicity and nitrogen narcosis) when breathed at high pressures, such as when people dive to very deep depths.

Other diving-related disorders

Diving in cold water can rapidly lead to a dangerously low body temperature (hypothermia), which causes clumsiness and poor judgment. Cold water can also rarely trigger fatal heartbeat irregularities in people with coronary artery disease. Other potential diving hazards include

  • Drowning

  • Bites and stings from various marine life

  • Sunburn and heat disorders

  • Cuts and bruises

  • Motion sickness

  • Immersion pulmonary edema

Drugs (prescribed, recreational, and some over-the-counter) and alcohol may have unanticipated, dangerous effects at depth, as can various medical conditions (see table Medical Conditions That May Preclude Diving).

Diving injuries can result in drowning if they cause any of the following:

  • Impaired thinking or drowsiness

  • Unconsciousness, weakness

  • Panic

  • Loss of balance and disorientation

The Divers Alert Network (; 24-hour emergency hotline, 919-684-9111) is an important resource that addresses the needs of recreational scuba divers around the world in two important ways:

  • It helps doctors provide emergency medical assistance to divers in need.

  • It promotes dive safety through research initiatives, educational services, and diving-related products.

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NOTE: This is the Consumer Version. DOCTORS: Click here for the Professional Version
Click here for the Professional Version
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