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.

Safety precautions: Divers should take precautions that minimize the risk of barotrauma and decompression sickness.

The risk of barotrauma can be decreased by equalizing the pressure in various air spaces, including the face mask (by blowing out air from the nose into the mask) and the middle ear (for example, by yawning or swallowing). Divers should avoid holding their breath and breathe normally during ascent, which should be no faster than 0.5 to 1 feet/second (0.15 to 0.3 meters/second), a rate that allows divers to gradually expel excess nitrogen and empty air-filled spaces (for example, the lungs and sinuses). Current recommendations also include a 3- to 5-minute safety stop at 15 feet (4.6 meters). Also, divers should not fly for 15 to 18 hours after diving.

Divers should be aware of and avoid certain diving conditions (for example, poor visibility or currents requiring excessive effort). Cold temperatures are a particular hazard because hypothermia can develop rapidly and compromise the diver's judgment and dexterity. Hypothermia can also cause potentially fatal abnormal heart rhythms in susceptible people. Diving alone is not recommended.

Recreational and sedative drugs and alcohol in any amount may have unpredictable or unanticipated effects at depth and should be strictly avoided. Nonsedating prescription drugs rarely interfere with recreational diving.

High risk factors for diving: Because diving can involve heavy exertion, divers should have above-average aerobic capacity (capacity for vigorous exercise) and they should not be limited by heart or lung disorders. Disorders that can impair consciousness, alertness, or judgment, such as seizures and diabetes that is treated with insulin (because it can cause low blood sugar levels [hypoglycemia]) generally prohibit diving. Special programs for divers with diabetes have been established. If there is any question, a doctor should be consulted. Although children younger than 10 years should not dive, programs that begin teaching children at age 8 have been successful. Most diving instructors are familiar with guidelines for teaching children to dive. Prospective divers should be evaluated for fitness and for factors that can increase the risk of mishaps and injury during diving by doctors who are familiar with diving.

High Risk Factors for Diving
Alcohol or drug abuse Chronic or short-term congestion of the nose and sinuses Diabetes, type 1 or type 2, that is treated with insulin (usually) Drugs that can cause drowsiness Fainting spells Gastroesophageal reflux if severe Habitual air swallowing Heart disorders, such as coronary artery disease, heart failure, irregular heart rhythms, valve disorders, and congenital heart defects that allow blood to leak from the venous to the arterial system Inguinal hernia that has not been repaired Impulsive behavior or being prone to accidents Lung problems*, such as asthma, lung cysts, emphysema, or previous pneumothorax Obesity† Older age† Panic disorder Physical disabilities Poor cardiovascular fitness Pregnancy Ruptured eardrum Seizures *Possible higher risk of lung barotrauma. †Higher risk of decompression sickness.

Professional divers may undergo additional medical tests, such as those for heart and lung function, exercise stress, hearing, and vision, as well as bone x-rays. In addition, adequate diver training is absolutely necessary.

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