jueves, 14 de enero de 2010

This Time, He’ll Be Left Breathless


GRAND CAYMAN ISLAND — As a doctor monitored his heart and his blood and breathing, David Blaine filled his lungs with pure oxygen and prepared to hold his breath — for 16 minutes, he hoped. Mr. Blaine is a famous magician, but he insisted that this was no trick.


Viktor Koen
TierneyLab

John Tierney discusses his attempts at breath holding at TierneyLab. Join the discussion.
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Further Reading
"Effects of glossopharyngeal insufflation on cardiac function: an echocardiographic study in elite breath-hold divers." Ralph Potkin et al. Journal of Applied Physiology, June 27, 2007.
"Physiological and clinical aspects of apnea diving." Claus-Martin Muth et al. Clinics in Chest Medicine, 2005.
"Refeeding David Blaine — Studies after a 44-Day Fast." M. Korbonits, D. Blaine, M. Elia, J. Powell-Tuck. New England Journal of Medicine, Nov. 24, 2005.
DavidBlaine.com
Performance Freediving.
Internal Association for the Development of Freediving.
Apneamania.com
Performancefreediving.com
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Mike Nelson for The New York Times
David Blaine, above, and in the pool with his trainer, Kirk Krak, top.
He was training to break the world record for breath-holding, a logical enough step in his other career. As a self-described endurance artist, he’d spent 35 hours atop a 105-foot pole and survived a week buried in a coffin. He’d fasted for 44 days in a box suspended over the Thames, a nutritional experiment that was written up in The New England Journal of Medicine (with Mr. Blaine listed as a co-author).
This breath-holding experiment, conducted last week at a swimming pool on Grand Cayman Island, was being run by Ralph Potkin, a pulmonologist in Los Angeles who is a researcher trying to understand the human propensity for going without air.
This ability isn’t new — it involves an ancient reflex shared with dolphins and other mammals — but it has only recently been rediscovered, thanks largely to the sport of free diving. Using just their lungs, free divers have kept going deeper and holding their breath longer than anyone expected.
“The empiric results have consistently exceeded theoretical predictions,” Dr. Potkin said. He is the team physician for the United States free-diving team, whose members were training at Grand Cayman Island along with Mr. Blaine.
A century ago, Houdini was celebrated for being able to hold his breath for three and a half minutes. Today even a novice can quickly learn to last longer than that, as I discovered under the tutelage of Kirk Krack, the free-diving coach who has been training Mr. Blaine for his world-record attempt. (For a breathless account of my 3 minutes and 41 seconds underwater: nytimes.com/tierneylab.)
Researchers in the 1960s calculated, based on lung capacity and the effect of water pressure, that humans couldn’t dive deeper than 165 feet. Today free divers are going down more than 600 feet and returning in apparently fine shape. Most of the time.
The day before his attempt in the pool, Mr. Blaine was practicing in the ocean and told me he was headed down for a dive of 100 feet, so routine that he didn’t bother doing the usual preparatory ritual: a slow, steady “breathe-up,” followed by exhalations to purge carbon dioxide and then a final series of quick gulps of air called lung-packing.
I watched him disappear into the depths and then reappear about two minutes later, swimming smoothly upward next to a guide rope. But about 20 feet from the surface, he suddenly veered away from the rope and appeared to struggle upward with his arms flailing. His coach, Mr. Krack, recognized the symptoms of a blackout instantly and rushed to grab Mr. Blaine, supporting his head above the surface until he regained consciousness.
He’d succumbed, Dr. Potkin said, to one of the most common and sometimes fatal dangers of free diving — and one of the reasons you shouldn’t try any prolonged breath-holding unless someone like Mr. Krack is supervising.
“Divers rarely get into trouble at depth,” Dr. Potkin said. “But as the diver approaches the surface, the decreasing water pressure causes a drop in pressure of the oxygen in the brain. If the level in the brain gets too low, it’s like a switch: lights out.”
Mr. Blaine, predictably, seemed untroubled once he recovered. What’s a little blackout to a guy who was once encased in a block of ice for 63 hours? He blamed it on overconfidence (he’d kept going 20 feet deeper than planned) and on his relative inexperience with diving.
His specialty is static apnea: holding your breath while remaining immobile in a swimming pool. It requires some of same skills as being buried alive for a week, Mr. Blaine said: “It’s all in your mind. You’ve got to stay calm and slow everything down.”
The natural impulse to stop holding your breath (typically within 30 seconds or a minute) is not because of an oxygen shortage but because of the painful buildup of carbon dioxide. Mr. Blaine said he began trying to overcome that urge when he was a child in Brooklyn and at age 11 managed to hold his breath for three and a half minutes.
In his current training, he said, he does exercises every morning in which he breathes for no more than 12 minutes over the course of an hour, and he sleeps in a hypoxic tent in his Manhattan apartment that simulates the thin air at 15,000 feet above sea level.
He has been concentrating on lowering his oxygen consumption by slowing his metabolism, partly through diet (he fasted for 18 hours before the breath-hold in the pool) and partly through relaxation. In a test by Dr. Potkin, Mr. Blaine on command quickly lowered his heart rate by 25 percent.
“David seems to have a phenomenal ability, like Buddhist monks, to control his body,” Dr. Potkin said.
When Mr. Blaine began his breath-hold in the pool, his heart rate during the first minute fell to 46 from 81, a drop that was not entirely his own doing. Immersing the face in water produces a protective action in humans similar to that in dolphins, seals, otters and whales. Called the mammalian diving reflex, it quickly lowers the heart rate and then constricts blood vessels in the limbs so that blood is reserved for the heart and the brain.
By exploiting that reflex, free divers can remain active underwater for more than four minutes, and much longer if they remain still. The world-record holders have exceeded nine minutes after filling their lungs with ordinary air, and more than 16 minutes after inhaling pure oxygen.
As Dr. Potkin monitored the electrodes hooked up to Mr. Blaine, Mr. Krack was in the pool with him watching for danger signs, like blue lips, and periodically instructing him to move a finger to show he was conscious. Otherwise, Mr. Blaine remained motionless until he heard he’d hit 16 minutes.
He emerged and broke the surface at 16:09 — stopping, as he’d planned, just shy (by five seconds) of the Guinness World Record for pure-oxygen apnea. He said he could have gone longer but wanted to hold off until his formal attempt on April 30, in front of Guinness judges and a live television audience on “The Oprah Winfrey Show.”
“It felt pretty good,” Mr. Blaine said right after emerging, sounding perfectly lucid and smiling with pink lips. “I wasn’t even there most of the time. I imagined being deep in the ocean.”
Any pain during the 16 minutes?
“Not even a little bit,” he replied.
No one is sure of the long-term neurologic effects of such prolonged apnea, Dr. Potkin said, but his examination of Mr. Blaine (including the subsequent results from blood tests) didn’t turn up any problems or abnormalities.
“Many doctors still don’t realize the body can tolerate prolonged apnea so well,” Dr. Potkin said. “My hope is to understand the process so we can apply the lessons to help people with heart and lung disease and neurological problems.”
Mr. Blaine said he too hoped there would be some long-term benefit from his efforts, but his immediate concern was breaking the world record. He made 16 minutes look easy last week, but doing it at a swimming pool in the Caribbean isn’t the same as doing it on live television. Even a Buddhist monk might have a hard time controlling his heart rate on “Oprah.”