学文网在吕克・贝松的成名作《碧海蓝天》(Le Grand Bleu, 1988)中,男主角雅克这样描述海底:“你知道怎么样才能遇见美人鱼吗?当你游到海底,那里的水更蓝。在那里,蓝天变成了回忆,你就躺在了寂静里,呆在那里,决心为她们而死。只有这样,她们才会出现,她们来问候你,考验你的爱。如果你的爱够真诚,够纯洁,她们就会和你一起,然后把你永远地带走。”这是多么美的描绘啊!现实中,参加自由潜水的人有的是为了挑战人类极限,有的则是希望以全新的角度感受海洋。
自由潜水就是不携带氧气瓶而尽可能深地潜入海中,像鱼一样。自由潜水中最纯粹的一种叫“恒定重量潜水”,指潜水者下潜与浮上来时保持自身所受重力不变;与之相对应的称为“无限制潜水”,潜水员下潜时借助重力装置,浮上来时借助浮力装置。一起来看看这种潜水运动的原理和发展历程。
How can you dive 200 meters in one breath?
Actually, if you’re a landlubber[旱鸭子], what you’re
probably wondering is: How is it possible for anyone to dive deep into the ocean without an oxygen tank in the first place? If humans were meant for such activity, we’d have gills[腮] and finned[有鳍的] extremities[四肢], wouldn’t we?
Well, what might seem like an impossible to ordinary people is merely a challenge to freedivers, who’ve trained their bodies and minds to function underwater for long periods without taking a breath. Freediving’s Michael Phelps equivalent[相等物] is a 39-year-old Austrian named Herbert Nitsch. He is capable of going without a gasp[喘气] of air for more than nine minutes straight and has held 22 world records recognized by the International Association
for the Development of Freediving. In 2007, Nitsch
shattered[破坏] his own world record in the “no-limits”
category, in which divers are permitted to use a
ballast[镇重物] to help them descend[下降]. He reached a depth of 214 meters. To get a sense of the magnitude of his feat[壮举], imagine submerging[浸没] a 58-story skyscraper
and then swimming down to the first-floor lobby[大厅].
But Nitsch isn’t satisfied with that. He hopes
eventually to descend to 300 meters. That’s nearly as deep as the most accomplished scuba[水肺] divers in the world are able to go with oxygen.
So how is it that freedivers are able to dive so deep and last so long without taking a breath? One reason is the diving reflex[反射], an evolutionary adaptation that enables seals and dolphins to dive deep and stay
underwater for extended periods by slowing and/or
shutting down some physiological functions. As scientists have discovered, even though humans evolved on land, we’ve retained a trace of that reflex too. Freedivers have learned to push self-induced[自身诱导的] apnea[呼吸暂停] to new extremes through sophisticated[复杂的] mind-body control techniques.
So, what’s the science behind holding one’s breath? Are we really part dolphin?
Freediving History
People started diving into deep water and making
like[模仿] dolphins thousands of years ago, long before they understood why they had the ability to do it. Ancient Greek divers weighted themselves down and descended to depths of 30 meters or more to pluck[拔去] sponges[海绵] from the sea bottom. Because coastal dwellers[居民] have been freediving for many generations, you might think that they’ve developed
special genetic traits that make them better at it than
inlanders. But scientists say there’s no evidence of that.
All humans do share an evolutionary adaptation with air-breathing aquatic[水生的] animals
that makes it possible for them to dive and swim underwater
for a while without taking a breath. In 1870, French
physiologist[生理学者] Paul Bert observed that ducks had an amazing ability to slow their heart rate if they were forced to stay underwater. Scientists went on to discover that immersion[沉浸]
in cold water or even simply holding your breath triggers[引发]
something called the diving reflex, which the body uses to conserve[保存] oxygen. When the reflex kicks in, your pulse slows and your circulatory system constricts[收缩], and blood is shunted[转移到(其他地方)] away from your muscles, skin and visceral[内脏的] organs, guaranteeing that your heart and brain get first dibs[优先权].
For years, scientists believed that humans were capable of enduring without oxygen for only a few minutes and that they couldn’t dive deeper than 50 meters, because the pressure would shrink their lungs and crush their rib cages[胸腔]. But in the 1960s and 1970s, divers disproved that myth. As it turns out, a phenomenon[现象] called “blood shift” causes the lungs to fill with plasma[血浆], preventing collapse[萎陷].
Freediving Today
In 1976, French diver Jacques Mayol became the first human to descend to 100 meters. Mayol studied Indian yoga and the breathing techniques of kung-fu-practicing Shaolin monks. He adapted those mind-body control methods to slow his pulse from 60 to 27 beats per minute underwater, enabling him to dive deeper and longer. In doing so, he revolutionized freediving and paved the way for Herbert Nitsch’s generation of divers to push the limits even further.
It’s fairly easy to get into freediving. It doesn’t
require a lot of expensive equipment a wet suit for warmth, a mask, and a set of special
flippers[潜水用橡皮制鳍状肢] can be done. And according
to freediving expert and author Terry Maas, with
competent[胜任的] instruction and a little practice,
novices[初学者] quickly can learn to stay under for 45
seconds, long enough to descend as far as nine meters and experience the ocean from a new angle.
But going without oxygen for longer periods and diving to serious depths isn’t for novices. Professional divers must endure strict training to develop their lung capacity[肺活量] and control their pulse rates. They also use special safety equipment, such as balloon systems to help them return to the surface more quickly.
Even then, tragedies sometimes occur. In 2002, French diver Audrey Mestre was attempting to set a no-limits depth record off the coast of the Dominican Republic, when equipment malfunctions[故障] kept her underwater too long. She lost consciousness[知觉]
during her ascent[上升] and died.
Therefore, freediving is a sport which can be very dangerous if you don’t have proper training, and you should NEVER try any form of freediving on your own.
人如何能仅凭一口气就下潜
200米?
实际上,如果你是旱鸭子,你可能会为此感到疑惑:首先,一个人怎么能不带氧气瓶就深潜到海里呢?如果说人类天生就擅长此类运动,我们就该长出鳃和带鳍的四肢来了,不是吗?
对于普通人来说看似不可能的事情,在自由潜水者看来只不过是一项挑战罢了。他们已经将其身心训练到能够在水下呆很长时间也无需换气。在自由潜水界,39岁的奥地利人赫伯特・尼奇的名气相当于(泳坛的)迈克尔・菲尔普斯。他能够一口气连续下潜9分多钟,而且保持着22项由国际自由潜水发展协会认可的世界纪录。2007年,尼奇打破了由他自己保持的“无限制”类别的潜水世界纪录――在这一类别,潜水者可以使用镇重物来帮助下潜。他下潜到214米的深度。如果不知道这一壮举究竟有多厉害,你可以想象将一幢58层的摩天大楼沉入水中,然后向下游至其首层大厅。
但尼奇并不满足于此。他希望最终能下潜至300米的深度。这几乎是世界上技艺最高超的带水肺潜水者能够到达的最大深度――只不过他们需要携带氧气。
那么,自由潜水者们为什么能够下潜这么深、这么久也不需要换气呢?其中一个原因是潜水反射。这种进化适应性使海豹和海豚能够潜至深水,并通过放缓和(或)关闭某些生理机能来延长待在水下的时间。科学家们发现,虽然人类在陆地上进化,我们依然保留着些许此类反射。通过复杂的身心控制技巧,自由潜水者们学会把自我诱导式的闭气能力推向新极限。
那么,在屏住呼吸的背后又存在着怎样的科学原理呢?我们真的是半人半海豚吗?
自由潜水的历史
数千年前,在还不明白为什么自己有这种能力之前,人类就开始像海豚一样潜入深水之中。古希腊的潜水者给自己加上重物,潜入水下30米或更深的海底采摘海绵。由于沿海居民世世代代都进行自由潜水,你也许认为他们会发展出特殊的基因特征,使其在这方面强于内地居民。但科学家说没有证据证明
这个说法。
所有的人类确实和呼吸空气的水生动物共有一种进化适应性,使得他们能够在水下无需换气就能进行潜水或潜游一阵子。1870年,法国生理学家保罗・贝尔
发现鸭子具有一种令人吃惊的本领。如果强制它们潜在水下,它们就会减慢其心跳速率。科学家们接着发现,沉入冷水中――或仅仅屏住你的呼吸――就能引发某种被称为“潜水反射”的反应,即身体用来保存氧气的反应机制。反射发生时,你的脉搏开始放缓,循环系统收缩,血液被调离肌肉、皮肤和内脏器官,保证你的心脏和大脑得到优先供应。
多年来,科学家认为人类离开了氧气只能坚持几分钟,而且无法下潜超过50米,因为(水体)压力会使肺部收缩并压碎胸腔。但在二十世纪六七十年代,潜水者驳斥了这一说法。原来,一种被称为“血液转移”的现象使肺部充满血浆,防止(肺)萎陷。
自由潜水的今天
1976年,法国潜水者雅克・马约尔成为下潜至水下100米的第一人。马约尔学过印度瑜伽和少林和尚练功夫所用的呼吸技巧。通过那些身心控制法,他在水下可以将脉搏由每分钟60次降至27次,从而下潜得更深更久。他这一举措彻底改变了自由潜水这项运动,并为赫伯特・尼奇这一代潜水者铺平了道路,让他们得以将极限推至更远。
要学习自由潜水非常容易。它不需要很多昂贵的装备――一套用于保暖的潜水服、一副面具和一套特制的鳍状肢足矣。按照自由潜水专家和作家
特里・马斯的说法,只需要合格的指导和一点点练习,初学者很快就能在水下呆45秒,这时间足够下潜到9米深,从一个全新的角度去体验海洋。
不过,初学者并不适合不携带氧气在水下待更长时间,或者潜入危险的深度。专业潜水者必须经受严格的训练来提高肺活量,控制脉搏率。他们还要使用气囊系统等特殊的安全装备来帮助他们更快地返回水面。
即使如此,悲剧还是时有发生。2002年,法国潜水者奥德蕾・梅斯特在多米尼加共和国的海岸试***创造一项无限制纪录,但装备故障使她在水下滞留时间过长。她在上浮过程中失去了意识,最终身亡。
因此,如果你没有经过正确的训练,自由潜水是一项非常危险的运动,绝对不要独自尝试任何一种自由
潜水哦。
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