What is recreational scuba diving?

Recreational scuba diving is defined as pleasure diving to a depth of up to 130 feet without decompression stops. Recreational scuba diving has become very popular in the past 20 years. There are almost 9 million certified divers in the United States alone.

Several scuba certifying agencies offer training for divers, from beginners to experts. Three of these agencies are the Professional Association of Diving Instructors (PADI), the National Association of Underwater Instructors (NAUI) and Scuba Schools International (SSI). Basic classes involve classroom instruction and training in a pool and in open water settings. The most popular courses last from 4 to 8 weeks.

What are the common medical problems of scuba diving?

The most common medical problems are simple "squeezes." These can affect your middle ear or face mask during descent. 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 in 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. Can I be seriously hurt while scuba diving?

Yes. The most dangerous medical problems are barotrauma to the lungs and decompression sickness, also called "the bends."

Barotrauma occurs when you are rising to the surface of the water (ascent) and gas inside the lungs expands, hurting surrounding body tissues. In some divers, these lung injuries can be bad enough to cause lung collapse (pneumothorax). The injuries may also allow free air bubbles to escape into the blood stream. This is called arterial gas embolism. Arterial gas embolism often causes chest pain, breathing trouble and neurologic problems such as stroke.

Decompression sickness occurs during ascent and on the surface of the water. Inert nitrogen gas that is dissolved in body tissues and blood comes out of solution and forms bubbles in the blood. The bubbles can injure various body tissues and may block blood vessels. The most common signs of severe decompression sickness are dysfunction of the spinal cord, brain and lungs.