How low can you go?

Humans have used breath-hold diving as a hunting and pearl-finding technique for longer than records go back. Some humans, like Saulvin featured in the clip below, have such well-developed adaptations to diving that they can dive for extended periods and become quite effective marine hunters near the shore. However, if you are anything like me, the clip below begs the question:

What limits could a well-adapted human reach with training? What’s the world record?

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Since we’re all impressed by what humans are able to achieve, even if it is nothing compared to our marine-living friends, I thought we’d dedicate some webspace to the human record breakers! (It has to be said, this attempt captured below didn’t win George any awards…)

 

Free Diving

William Trubridge is the current free-diving world record holder reached a depth of 101m in December 2010 without the help of weights or fins. He was born in New Zealand on May 24th, 1980.

William Trubridge, current world freediving record holder: 101m.

There are many different disciplines of free-diving which are classed by different rules on what the diver is allowed to use for assistance in order to achieve greater depths. However, Trubridge holds the record for the greatest depth reached by mankind on a single breath-hold without any assistance from fins, weights or pulleys.

 

This first video shows Trubridge descending to the 101m mark.

And this video captures the moment when Trubridge surfaces, world record attempt complete! It is important, when a human breath-hold diver surfaces, to give them enough time to recover and ‘come round’ (from a state which is  almost as close to unconsciousness as the human body could withstand!) before one can be sure that the diver is safe and not suffering from the effects decompression sickness.

Longest Breath Hold

The record for the longest breath-hold whilst remaining still underwater (known as “static apnea”) is held by Stephane Mifsud and stands at a whopping  11 minutes and 35 seconds.

Stephane Misfud, world record holder for the longest underwater breath hold, standing at 11 minutes 35 seconds.

Impressed?! You should be!! Give it a go yourself… Grab a watch (and maybe a friend to keep an eye on you!) take a deep breath and see how you get on… I can just about make it to 1 minute before the carbon dioxide build-up in my blood causes me to gasp for air again! Imagine trying to forage for food at the same time…!

This brings us on nicely to the true record holders. The real deal

Expert Divers…

People often flatter themselves by placing themselves at the top of the evolutionary tree. It is true, of course, that in many ways humans are more advanced than any other animal. But despite the invention of flying machines and submarines, some animal tricks simply seem out of our reach… And one such example is that of  long-term breath-hold diving.
If you remain unconvinced about our ability to compete with diving mammals and birds, check out this graph. It shows the amount of time different species can dive for, and how deep they can dive. Their routine dives are compared to the maximum depth the species has been recorded at. The graphs are drawn to scale so that different species can be easily compared. To enlarge the image, click on it:

This graph, adapted from Kooyman and Ponganis (1998a), shows both the maximum and routine depths and durations which diving mammals, birds and reptiles are able to achieve. It provides easy comparison and puts into context how well-adapted diving mammals are to life underwater compared to humans!

At present, the greatest diversification and distribution of living sea creatures (not counting fish!) is found in the endothermic mammals and birds. Since they are able to generate their own body heat, they are not restricted to warm waters. As a result, they have spread into temperate and even polar seas, where they are most abundant. Hundreds of millions of years ago, reptiles dominated the seas with some of the most unusual vertebrates that have ever existed… Nowadays there are only a handful of sea turtle species, one lizard (the Galapagos marine iguana) and about 50 species of sea snake which are adapted as reptiles to live in the sea. The deepest-diving of these, the leatherback sea turtle, is inlcuded above for comparison.

The Podium

… So the sperm whale takes gold for the deepest dive recorded off a single breath, reaching depths deeper than 2000m… a distance almost 5 times the height of the Empire State Building!! The Northern Elephant seal takes the prize for the longest amount of time spent underwater during a dive. Individuals have been recorded diving for up to 2 hours on one breath! They’re not just staying still during this time… Seals are foraging for food, escaping from predators. In other words: exercising! It takes the fittest men in the world just over 2 hours to run the London Marathon… imagine doing it holding your breath. Perhaps what even more impressive is that they only require a matter of minutes at the surface before they are able to repeat the whole process.

The sperm whale is able to dive to depths almost 5 times the height of the Empire state building; northern elephant seals can remain submerged for almost as long as Emmanuel Mutai took to win the 2011 London Marathon (pictured).

The video below gives us some interesting footage of our diving champions, but it is probably best watched on mute as some of the facts given about the sperm whale and the Weddell seal are highly questionable! (For example, “3km” should be 2km when talking about the greatest recorded depth of the sperm whale dive, and Weddell seals “dive continually” for long-lasting bouts – i.e repeated short dives – rather than one long breath-hold dive lasting for “11 hours”)

**NEXT PAGE** Tricks of the Trade: physiological adaptations of deep-sea divers




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