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 N₂ 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 Table 3: Injury During Diving or Work in Compressed Air: Specific Medical Contraindications to Diving.

Table 3
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Specific Medical Contraindications to Diving Contraindication Specific Examples or Adverse Effects Lung disorders Active asthma Bronchiectasis COPD 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 Syncope 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 Pregnancy 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 Specific Medical Contraindications to Diving Contraindication Specific Examples or Adverse Effects Lung disorders Active asthma Bronchiectasis COPD 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 Syncope 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 Pregnancy 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

Last full review/revision April 2013 by Alfred A. Bove, MD, PhD