What is recreational scuba diving?

SCUBA is short for "Self-Contained Underwater Breathing Apparatus." Scuba divers, while underwater, breathe through a mouthpiece that is attached to a tank of compressed air. Scuba diving is defined as pleasure diving to a depth of 130 feet.

Several scuba-certifying agencies offer training for divers, from beginners to experts. Three agencies that offer certification courses are the Professional Association of Diving Instructors (PADI), the National Association of Underwater Instructors (NAUI) and Scuba Schools International (SSI). Basic courses involve classroom instruction, training pools and open-water settings. Diving certification, which allows you to rent equipment, request tanks to be re-filled and dive without supervision, can be attained in as little as five open-water dives. Most scuba-certifying agencies highly recommend you dive in a "buddy system" (a group of 2 or 3 divers).

What are the most common problems of scuba diving?

The most common medical problems are simple middle ear "squeezes." Squeezes cause pain in your ears. The pain is caused by the difference in pressure between the air spaces of your ears and mask and higher water pressure as you go deeper into the water. Squeezes that affect the inner ear or sinuses are less common.

Cuts, scrapes and other injuries to the arms and legs can be caused by contact with fish and other marine animals, certain species of coral and hazards such as exposed sharp metal on wrecks or fishing line.

What dangerous medical conditions are possible when I am diving?

• Inner ear barotrauma. This condition may occur if you have trouble clearing (equilizing the pressure between the middle ear and the water-- sometimes called "popping your ears") during a dive. The result is severe dizziness and hearing loss.
• Pulmonary barotrauma. This condition is the result of improper breathing during the ascent to the surface or, occasionally, from diving with a respiratory tract infection. Symptoms include chest pain, shortness of breath and hoarseness.
• Arterial gas embolism (AGE). This is a type of barotrauma in which bubbles enter the blood stream and travel to the brain. Symptoms such as numbness or tingling of the skin, weakness, paralysis or loss of consciousness may occur. This is a serious diving injury.
• Decompression sickness ("the bends"). This condition occurs during ascent and on the surface of the water. Nitrogen gas that is stored in body tissues and blood comes out of solution and forms bubbles in the blood. The bubbles can injure various body tissues and block blood vessels. The most common signs of severe decompression sickness are dysfunction of the spinal cord, brain and lungs.

Remember: If you should develop any of the symptoms on this list during or after a dive, seek medical care immediately.

How common are medical problems in scuba diving?

Fortunately, serious medical problems are not common in recreational scuba divers. While there are millions of dives each year in the United States, only about 90 deaths are reported each year worldwide. In addition, fewer than 1,000 divers worldwide require recompression therapy to treat severe dive-related health problems.

How can I lower my risk of medical problems?

Most severe dive-related injuries and deaths happen in beginning divers. To be safe, always dive within the limits of your experience and level of training. Good rules to follow for safe diving include:

1. Never try a dive you're not comfortable with. During descent, you should gently equalize your ears and mask. At depth, never dive outside the parameters of the dive tables or your dive computer (information that helps you avoid decompression sickness).
2. Never hold your breath while ascending. You should always ascend slowly while breathing normally.
3. Become familiar with the underwater area and its dangers. Learn which fish, coral and other hazards to avoid so injuries do not occur. Be aware of local tides and currents.
4. Never panic under water. If you become confused or afraid during a dive, stop, try to relax and think the problem through. You can also get help from your dive buddy or dive master.
5. Never dive without a buddy.
6. Always plan your dive; then always dive your plan.
7. Be sure that your diving equipment can handle the dive you have planned and that the equipment is working well.
8. Don't drink alcohol before diving.
9. Never dive while taking medicine unless your doctor tells you it's safe.
10. Diving can be dangerous if you have certain medical problems. Ask your doctor how diving may affect your health.
11. Cave diving is dangerous and should only be attempted by divers with proper training and equipment.
12. If you don't feel good or if you are in pain after diving, go to the nearest emergency room immediately.
13. Don't fly for 12 hours after a no-decompression dive, even in a pressurized airplane. If your dive required decompression stops, don't fly for at least 24 hours.

What should I do in a diving emergency?

If you or one of your dive buddies has an accident while diving, call the Divers Alert Network (DAN) emergency telephone line (919-684-4326). DAN is located at Duke University Medical Center in Durham, N.C. Doctors, emergency medical technicians and nurses are available 24 hours a day to answer your questions. If needed, they will direct you to the nearest hyperbaric chamber or other appropriate medical facility. If you would like to discuss a potential diving-related health problem, contact the non-emergency Divers Alert Network telephone line (800-326-3822).

What is a hyperbaric chamber?

A hyperbaric chamber is a facility where you are placed under increased pressure. It's similar to being underwater. This can often help injury from arterial gas embolism or decompression sickness by shrinking bubbles and allowing them to pass through your blood vessels.