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 and help prevent or lessen the risk of diving-related injuries.
Equalize 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)
Avoid holding their breath and breathe normally during ascent, which should be no faster than 0.5 feet/second (0.15 meters/second), a rate that allows divers to gradually expel excess nitrogen and empty air-filled spaces (for example, the lungs and sinuses)
Make all required stops according to the depth and time of the dive required by the dive tables or computer
Include a 3- to 5-minute safety stop at 15 feet (4.6 meters)
Not fly for 15 to 24 hours after diving
To decrease other diving risks, divers should be aware of and avoid certain diving conditions, for example
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.
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 preclude diving. Special programs for divers with diabetes have been established. If there is any question, a doctor should be consulted. Individuals who have experienced spontaneous collapse of the lung (pneumothorax) should not dive.
Although traditional guidelines have suggested that 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.
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.