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Freediving, also called breath-hold or apnea diving, is diving without benefit of a breathing apparatus. Freediving is a sport with several different competition categories such as diving with or without fins, weight-sleds, depth records set in the ocean and breath-holding records set in pools. There are both men and women’s competitions in professional freediving.
Freediving requires extreme physical fitness, mental discipline and training. While human brain cells do not tolerate periods of apnea longer than five minutes and can become damaged after just three minutes, an understanding of the body’s reflexes, combined with training, allows world-class professionals in freediving competitions to hold their breath up to nine minutes. This is due mainly to taking advantage of the mammalian diving reflex.
The mammalian diving reflex is a key factor in any freediving sport. When a person is submerged in water, certain processes naturally take over. Heart rate begins to slow. With practice, it can beat as little as four times per minute. Blood vessels constrict in the limbs, forcing blood into the body’s vital organs. At the same time, blood vessels in the lungs fill with plasma, reducing volume to prevent them from collapsing in on themselves.
When the heartbeat slows, the body saves energy. Air trapped in the lungs continues to oxygenate the blood. This extends the amount of time the body can safely go without breathing. However, because there is no respiration, carbon dioxide (CO2) builds in the bloodstream and muscles. The build-up of CO2 is a limiting factor in freediving. When the body becomes saturated with CO2, it trips an overwhelming reflexive response to breathe.
Inexperienced freedivers sometimes hyperventilate before freediving, believing this saturates the blood with oxygen, allowing a longer dive. In reality, it does not increase oxygen, but removes CO2 from the blood, simply delaying the reflexive need to breathe. This is extremely dangerous and even life threatening, as the body can run out of oxygen before the diver feels a need to take a breath. When this happens, the diver can black out underwater. Shallow water blackout is believed to be responsible for many drowning accidents.
Freediving is an exhilarating but potentially dangerous sport that can result in severe injury or death. Pressures on the body in deepwater freediving can reach 235 pounds per square inch (16.5 kilograms per square centimeter). Though freediving has roots that reach back over 4,000 years, when people often dived for pearls and food, today’s enthusiasts are encouraged to take professional classes to learn how to enjoy this extreme sport safely. For those that follow safety first, freediving can be a beautiful way to experience the ever-exotic underwater world.
I don't think I want to try competitive freediving, but I would like to get all of the proper freediving equipment, like a mask and fins, and swim around a tropical island some day. I've tried scuba diving before, and it's a really enjoyable sport, but I always felt restricted by all that gear.
I don't know where they offer freediving training, but I'm sure they advertise that sort of thing in diving-related magazines. I would probably wait until I was in much better condition before going out on a real freediving vacation, however.
I've seen freediving competitions on TV a few times, and they scared me to death. I can hold my breath for about a minute or so, but then my lungs will start to burn and I feel like I'll die if I don't get another breath soon. I don't see how these freedivers overcome that feeling, but I guess it's a matter of training and experience, like anything else.
The competitors I saw would follow a rope down into the ocean and try to grab the deepest flag they could reach. There were scuba divers positioned every so many feet in case someone panicked or dove too deep to make it back to the surface safely. I think I saw one freediver signal for a rescue, and one of the scuba divers put a mask on him.
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