Great book, and an interesting set of parallels to this news story: similar depth, similar mode of discovery, sub sunk near enemy coastline, enduring mystery. I won't spoil anything for you, but suffice it to say that the book leaves little doubt that a free ascent from 200 feet is almost always deadly.
The Last Deep Dive (Page 2)
Pipin's years of relentless training have resulted in extraordinary abilities. At peak performance his lungs can hold eight liters of air, twice the normal amount for a man his size. At the bottom of a descent his heart rate has been reduced to an unparalleled 8 beats per minute, though more commonly it drops to 20 to 30 beats per minute while diving. (The average human rate is about 65 beats per minute.) At rest he can hold his breath for nearly eight minutes. (Dolphins can do so for up to fifteen minutes.) Physicians and scientists have studied, tested, and probed him seeking to learn how he does this, and thus perhaps learn more about what the body is capable of achieving. To them he is a mystery. CBS, NBC, and the Discovery Channel have produced programs marveling at his accomplishments. In fact when Audrey Mestre first met him, she was a marine biology student specifically studying his body, the way an art history major might study Michelangelo's David.
Today's top divers have devised high-tech tools to take them as deep as possible as quickly as possible. At the extreme end of the sport, called no-limits free-diving, champions like Pipin and Audrey use a heavy "sled" guided by a weighted metal cable to rapidly descend to a desired depth. Then they inflate an air bag to shoot them back to the surface. Safety divers with scuba gear are positioned along the length of the cable in case of emergency. But the risks are still great. One constant danger is something known as shallow-water blackout, which occurs when oxygen starvation causes a sudden loss of consciousness during a diver's ascent.
That risk and many others are worth taking, divers say, because of the reward: the experience of a quiescence so euphoric it is hypnotic, even magical.
Right now I'm at the part of the book where they dive on the wreck for the second time, and lose the CBS propmaster from deep water blackout. But...if I discuss this further I'll use freepmail. The author seems compelled to through in extra flowery adjectives here and there in a way that's kind of jarring, but so far it's one of the best books about diving I've ever read, and I wouldn't want to ruin it for anybody else.