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Diving Precautions and Prevention of Diving Injuries

by Alfred A. Bove, MD, PhD

Diving is a relatively safe recreational activity for healthy people who have been appropriately trained and educated. Diving safety courses offered by national diving organizations are widely available.

Diving safety

Incidence of barotrauma can be decreased through active equalization of various air spaces, including the face mask (by blowing out air from the nose into the mask) and the middle ear (by yawning, swallowing, or performing a Valsalva maneuver). Divers should avoid holding their breath and breathe normally during ascent, which should be no faster than 0.15 to 0.3 m/sec (0.5 to 1 ft/sec), a rate that allows for gradual offloading of N 2 and emptying of air-filled spaces (eg, lungs, sinuses). Divers should ascend with decompression stops as specified in published guidelines (eg, the decompression table in the US Navy Diving Manual ). Current recommendations also include a 3- to 5-min safety stop at 4.6 m (15 ft) for further equilibration. Also, divers should not fly for 15 to 18 h after diving.

Divers should be aware of and avoid certain diving conditions (eg, poor visibility, currents requiring excessive effort). Cold temperatures are a particular hazard because hypothermia can develop rapidly and affect judgment and dexterity or induce fatal cardiac arrhythmias in susceptible people. Diving alone is not recommended.

Recreational or sedative drugs and alcohol in any amount may have unpredictable or unanticipated effects at depth and should be strictly avoided. Otherwise, prescription drugs rarely interfere with recreational diving, but if the disorder being treated is a contraindication to diving, the dive should not be pursued.

Contraindications to diving

Because diving can involve heavy exertion, divers should not have a functionally significant cardiovascular or pulmonary disorder and should have above-average aerobic capacity. Disorders that can impair consciousness, alertness, or judgment generally prohibit diving. If there is any doubt as to whether diving is contraindicated by a specific disorder, a recognized expert should be consulted. For specific diving contraindications, see Specific Medical Contraindications to Diving.

Specific Medical Contraindications to Diving


Specific Examples or Adverse Effects

Lung disorders

Active asthma



Cystic fibrosis

History of spontaneous pneumothorax

Interstitial lung disease

Lung cysts

Marfan syndrome

Cardiovascular disorders

Heart failure

History of significant ventricular arrhythmias

Hemodynamically significant intracardiac shunt

Significant coronary artery disease

Psychologic disorders

Panic or phobia

Structural disorder

Unrepaired inguinal hernia

Neurologic disorders

Seizure disorder


Metabolic disorders

Extreme obesity

Type 1 or type 2 diabetes mellitus treated with insulin (a relative contraindication)

Ear, nose, and throat disorders

Allergic rhinitis

Perforated tympanic membrane

Upper respiratory infection


Possible risk of birth defects and fetal injury due to decompression sickness

Habitual air-swallowing

GI overinflation during ascent due to swallowing pressurized air at depth

Poor exercise tolerance

Inadequate physiologic response to adverse diving conditions

Severe gastroesophageal reflux

Aggravated by loss of gravity effect on the abdomen during submersion

Children < 10 yr

Incomplete understanding of the physics and physiology needed for safe diving

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