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.
(See also Overview of Diving Injuries.)
Safety precautions
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 nitrogen 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 Diagnosis and Treatment of Decompression Sickness and Arterial Gas Embolism, a chapter in the U.S. Navy Diving Manual). Current recommendations also include a 3- to 5-minute safety stop at 3 to 4 m (10 to 15 ft) for further equilibration. Also, divers should not fly for 12 hours after a single no-stop dive or 18 to 24 hours after multiple dives or dives requiring decompression stops.
Divers should be aware of and avoid certain diving conditions, including the following:
Poor visibility
Currents requiring excessive effort
Cold temperatures
Diving alone
After use of illicit drugs, sedatives, or alcohol
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.
Illicit or sedative drugs and alcohol in any amount may have unpredictable or unanticipated effects at depth and should be strictly avoided. Otherwise, prescription medications 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 adequate aerobic capacity for the type of diving performed. Disorders that can impair consciousness, alertness, or judgment generally contraindicate 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 Specific Medical Contraindications to Diving.
Specific Medical Contraindications to Diving
Contraindication | Specific Examples or Adverse Effects |
|---|---|
Lung disorders | Active asthma Chronic obstructive pulmonary disease (COPD) History of spontaneous pneumothorax Lung cysts or bullae Chronic hypercapnia |
Cardiovascular disorders | History of significant ventricular arrhythmias Hemodynamically significant intracardiac shunt or any right-to-left shunt (eg, atrial septal defect, tetralogy of Fallot) |
Psychologic disorders | |
Structural disorder | Unrepaired hernia |
Neurologic disorders | |
Metabolic disorders | Extreme obesity |
Ear, nose, and throat disorders | Upper respiratory infection |
Pregnancy | Possible risk of birth defects and fetal injury due to decompression sickness |
Habitual air-swallowing | Gastrointestinal 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 years | Incomplete understanding of the physics and physiology needed for safe diving |
More Information
The following English-language resources may be useful. Please note that THE MANUAL is not responsible for the content of these resources.
Divers Alert Network: 24-hour emergency hotline, 919-684-9111
Duke Dive Medicine: Physician-to-physician consultation, 919-684-8111
U.S. Navy Diving Manual: Detailed reference guide published by the US Navy detailing diver training and diving operations
