By freedivinguae

Why Freediving Is My New Favorite Way to Get Active on Vacation

“Learning to freedive takes any limitations we may feel about ourselves and blows them out of the water.”

When you go away for a tropical getaway, there’s no end to the list of ways that you can fit in fun physical activity. You’ve got beach volleyball, snorkeling, kayaking…the list goes on.

At one point or another, I’ve tried them all. Heck, the stand-up paddleboard (SUP) trend even had me doing yoga inversions on a board in the middle of the ocean. (OK, they were pretty horrible inversions, but still, I did them.) And SCUBA diving? I got certified several years back and now make it a priority to go diving each and every time I visit someplace with open water.

But it wasn’t until a recent trip to the Galápagos Islands with Lindblad Expeditions and National Geographic that I considered freediving—a form of deep-water diving where you simply hold your breath. In all honesty, when I first tried freediving, I didn’t even know it had a name. I was snorkeling with an underwater photographer, and when he dove down to get up close and personal with the sea turtles, manta rays, and even sharks that were just 20 or so feet below us, you bet your wetsuit that I was diving down after him to see what there was to see.

By the time I made it back up to the surface, I knew two things for sure. First, that what I just saw was awesome. And second, that I was out of breath and every muscle in my body was exhausted.

Apparently, our bodies are built for freediving and have a handful of mechanisms that kick in to help us do it.

“Humans have evolved to be freedivers,” Emma Farrell, a certified freediving instructor and owner of Go Freediving, tells SELF. “We spent several million years of our evolution living in the shallows, foraging for nutrient-dense food that fueled brain development, and escaping from land-based predators. During this time in the water, we evolved to lose our body hair, gain a layer of subcutaneous fat to keep us warm in the water, and developed the mammalian dive reflex, the physiological changes that occur in the body when we freedive to enable us to dive deeper, safer.”

For one, like seals and other water-loving mammals, humans experience a decrease in heart rate the second we dive into the water, Patrician Alexander, M.Sc., a researcher at Mid Sweden University who has studied the physical effects of freediving, tells SELF. This allows the body to conserve oxygen when it’s scarce. What’s more, blood reroutes away from the arms and legs and toward the heart, lungs, and brain to keep the high-priority organs working at top speed, he says. The blood around the lungs also works to protect the lungs from increasing water pressures as you go deeper and deeper. While most recreational freedivers swim 30 to 55 feet underwater, elites can go as deep as 130 feet (!!!).

And how’s this for trippy: As you descend, your lung volume actually decreases as the air within them compresses. As you swim back up to the surface, they expand back to their previous volume. Changes in air pressure also make your inner ears feel “full,” kind of like when you’re on an airplane, Alexander says.

“Even with basic training, we have a pretty remarkable ability to dive underwater,” he says. After all, we’re built for it.

Freediving is more than just awe-inducing—it’s actually a great way to challenge and tune into your body.

No matter how naturally freediving comes to us homo sapiens, that’s not to say it won’t push you. Swimming in general is a great workout, and when you add the currents that open waters provide, well, you can expect every muscle to be sore the next day. What’s more, if you decide to wear a wetsuit while freediving, which allows you to float at the surface of the water without too much effort (handy if you’re also snorkeling, or just in cold waters!), swimming down to depths will be an act of resistance training.

But perhaps the greatest physical benefit of freediving is that it gets you practicing deep, diaphragmatic breathing. To hold your breath for any length of time, you need to first take a big, deep breath, Farrell explains. That means relaxing the diaphragm to allow the lungs to fill more fully.

Diaphragmatic breathing enables you take in more oxygen, and increases vital capacity, the amount of air that we can take in and expel in a single breath. “This impacts all aspects of life and has huge associated benefits for all other sports,” says Farrell, who has worked with multiple U.K. Olympic ­­­­athletes across a wide range of sports to help increase their lung function and performance.

What’s more, diaphragmatic breathing also calms the body and mind and lowers the heart rate, Farrell says. Recent research in the journal Frontiers in Psychology found that deep, diaphragmatic breathing lowers levels of the stress hormone cortisol in the body to improve mood, and it also improves mental function and your ability to focus.

As far as Alexander is concerned, these mental benefits are what truly sets freediving apart from other water sports. “You become more in-tune with your body and it becomes easier to relax and dive longer,” he says. That way, you can really get the experience of freediving—being just “one of the fish” and hanging out with underwater animals in their natural habitat, with no air tanks or bulky equipment hanging on you or getting in the way. (I love SCUBA diving, but I do hate it when my tank bops me in the back of the head mid-dive!)

To Farrell, this “tuning into your body part” is important for improving confidence and self-esteem. “Learning to freedive takes any limitations we may feel about ourselves and blows them out of the water,” she says. “When you learn to hold your breath and dive to depth, you realize just what you are capable of, and how the barriers we feel are mostly self-created and self-imposed.

Before diving in, always make sure you’re doing it safely.

Like in all sports (especially underwater ones), staying safe when freediving is priority number one. “One of the most crucial considerations is to always dive with a buddy and be watchful of one another,” says Alexander, noting that in rare cases, freedivers can black out from too-low levels of oxygen to the brain. And, just like when snorkeling and SCUBA diving, it’s important to safely manage current, marine life, and boat traffic. Learning to equalize the pressure in the inner ear (again, like on an airplane) is important so that you don’t rupture the ear drum.

These are all things that a qualified freediving school and certified instructors can teach you. “The courses are great first exposure because they allow anyone to get the most out of the experience and in a safe learning environment,” Alexander explains. Check out PADI to learn about courses and find freediving centers wherever your next vacation takes you.


By freedivinguae

Dolphin diet study gives conservation clues

Wild dolphins need up to 33,000 calories a day, researchers have found – equivalent to about 60 portions of salmon.

In contrast, Olympic swimmers – who are smaller and less active – burn about 12,000 calories a day during training.

Studying the metabolic rates of whales and dolphins is important for their conservation, say scientists.

They found that a common bottlenose dolphin needs 10 to 25kg of fish each day to survive in the oceans.

The study was carried out on common bottlenose dolphins living in Sarosota Bay off Florida.

Adult and young dolphins were captured briefly to measure their resting metabolic rate.

This provides an estimate of how much a dolphin needs to eat in a day, said Andreas Fahlman of Woods Hole Oceanographic Institution and the Oceanografic Foundation in Spain.

“We can then add this up for all dolphins and estimate how much fish/prey they need,” he said.

“This may be vitally important when considering managing fisheries and making sure that the quota are not too high so that animals lack food.”

The researchers found that a 200 kg dolphin would burn between 16,500 and 33,000 calories a day, which is lower than expected.

In contrast, an Olympic swimmer carrying out intensive exercise might need around 12,000 calories.

For a dolphin, the amount of energy required depends on whether the animal is resting, sleeping, diving or swimming, as well as the temperature of the ocean.
Health check

Finding out more about the diet and energy requirements of whales and dolphin will help in their conservation, say the researchers.

They measured lung function in wild dolphins for the first time.

“Lung function testing of wild populations in different areas of the world may help us understand respiratory health in wild populations,” said Dr Fahlman.

“We can use this as a health check of various populations and thereby the environment. If the dolphins are sick, there may be problems with the environment.”

The research is published in the journal Royal Society Open Science.


By freedivinguae

Freediving photographer makes unsettling images of polluted seas

When freediver Janeanne Gilchrist noticed an increase in the amount of debris washing up on the shores of her favorite diving spots, she decided to do something about it.
To raise awareness of the problem, she created a collection of breathtaking images, transforming waste into art.
Gilchrist, who dives without breathing equipment off the coast of Scotland, began taking photos of debris in the water over a year ago. Since then she has photographed plastic bags, discarded sous’westers (fishermen’s hats), and entangled fisherman’s rope, all captured in beautiful light.

“I didn’t want to just document a piece of plastic in the water. There is a lot of imagery like that available to people but it doesn’t necessarily make them sit up and take notice,” explains Gilchrist. “The images are made from man-made debris, which shouldn’t be there. It looks ethereal and majestic – but it makes people go wow, that’s amazing, what is it?”
The Edinburgh-based photographer has been taking photographs underwater for over 10 years. In that time she has seen a drastic change.
“Sadly, over this period of time I have seen an increase of debris in the water. This is a large problem and it’s not just off the coast of Scotland. This is a global problem,” says Gilchrist.

Capturing the images was no small feat. Gilchrist, who has been diving for over 15 years, had to retrain herself to photograph underwater. She says that the conditions around Scotland can be very challenging and the currents “are playing with me and the objects the entire time.”
But in the end, Gilchrist stresses, the process is well worth it.
“The images are a one off. I can’t reproduce this work. It’s caught at a moment of time and at a location that you just can’t recreate again,” she says.
Freediving is when divers swim without an air tank or snorkel, holding their breath underwater. Gilchrist prefers this method as it allows her to move more freely
“The work is not for the faint hearted. You’re in cold water, holding your breath and you have to make sure you get the image at the right time,” she explains.
Gilchrist’s main goal with her work is to “evoke emotions and spark imaginations” that inspire conversations about the worldwide problem of pollution and climate change.
“The irony of my work is that I’m using waste that shouldn’t be there,” says Gilchrist. “We all need to come together and figure out a solution. Because by the time this plastic and rubbish gets into the water, the damage is already done.”
An exhibition of Gilchrist’s work, titled “Above, Below, Beyond,” will be shown until March 24, 2018, at the JD Ferguson Gallery in Perth, Scotland.

Source :

By freedivinguae

Dream jobs . . . and how to get them: from finance to free diving instructor

How Mike Board left a finance job in Canary Wharf and became an instructor in Indonesia

I remember sitting on the 10th floor of One Canada Square in London, the rain beating against the window, and thinking, “This isn’t what I want to be doing for the next 10 years”.

I was 38 and working as a consultant in the finance industry. I’d previously been a commando in the Royal Marines and I think that training gives you an amazing sense of belief in what you can achieve. So I left London to work in a bar in the French Alps for a season, then came here to Gili Trawangan, a tiny island just off the coast of Lombok in Indonesia. I faced a lot of questioning when I jacked in the job. But I think in my own mind I knew it wasn’t really a risk — if you work hard, you’ve always got the ability to start anew.

I started free diving by accident. I was working as a scuba instructor, and there would often be times I needed to dive down and do things without any equipment — to free an anchor, say, or to check the current. I really enjoyed the challenge and it became a question of “How deep can I go?” When I started researching techniques for holding my breath online I learnt what I was doing had a name — free diving — and that it was something you could do professionally. I went and did an instructor course in Thailand, and decided to open a school. Over the years I’ve added to it — there’s now a yoga studio and a vegetarian restaurant.

The basic set of skills for free diving really aren’t complex: you hold your breath and you swim underwater. It seems quite challenging because it taps in to one of our most basic fears, going somewhere you can’t breathe — but once you’ve got over that it’s easy. Then all you need to learn is how to swim using oxygen in the most efficient way. Out in the tropics we’ve got perfect conditions. You can learn to free dive to between 10 and 20 metres on a two-day course.

Gili Trawangan is an interesting island. It’s 2km by 3km, with no motorised traffic — we get around by bike or horse and cart. It’s become a bit of a party spot since I moved here eight years ago so we get a lot of gap-year students, but the ones who walk into the free diving shop tend to be the more interesting people.

I think that’s because the challenge of free diving is really internal. When you discover you can go down to 10 metres without panicking you’re so interested in what’s going on inside you that you’re not actually looking at the fish.

Once you’ve mastered the technique you can go out exploring on a breath hold. The waters around Gili are full of tropical fish, turtles and reef sharks, and you can get up close to them because they’re not spooked by the bubbles like they are with a scuba. You’re part of the natural environment.

When I’m not teaching I compete in free diving competitions. I’m 47, and in any other sport I would have stopped years ago, but this has actually been my best year: I dived to 108 meters and was in the world’s top five. By the time you get 100 metres down you’ve got an 11th of the volume of air in your lungs that you had at the surface. Some people talk about feeling a crushing pressure but I’ve always just felt totally absorbed — it’s a sort of meditation.

I think marines tend to go on to do quite odd things, so I don’t think my friends from that time look at me and think I’m doing anything more interesting than the next person. At the end of the day I’m running a business, but I get to do it in a tropical paradise, not sitting at a desk in London.


By freedivinguae

Freediving, a Yacht & The Ionian islands

We have been exploring new locations and discovering site gems for years. I remember diving in Dahab in 1999, and taking my first group there in 2001 – when The Blue Hole was strictly a 4×4 excursion, since then we seem to be bombarded with offers from further and further afield, promising a freediving experience like no other. Then, last year, a small sailing company, dedicated to delivering personal experiences contacted us: I was intrigued to see how much of a true expedition we could find just 3h away from London.

We sailed from the island of Kefalonia, the biggest of the Ionian Islands, as a location I have explored a few times getting tanks for the sled was easy on a stopover in Fiscardo, before checking out “The Cracken” as well as “Seal the Deal”. Two amazing natural surface formations. The Cracken being an invisible (at least up-to 5m away) crack, which effectively separated a huge rock from the mainland – about 30m long and 3m deep. As it twists and turns, the crystal clear water is reminiscent of a ridiculously exotic film location. A simply stunning find for our 1st day!

The Skipper deftly motored/sailed around the islands, sometimes sheltering from winds and high water behind them, sometimes taking us on open water to new unexplored territories. After a brief discussion on the 2nd day that went something like

“we cannot anchor in water deeper than 20m… but we would love to anchor in 80 – 90m”

“OK – we’ll work out a way”: every dive location we could think of was available to us. From the awe-inspiring “Eye of Cyclops” – a huge cave with an entrance (the eye) in the top at 20m and an exit at 30m – to the “Pressure Chamber” a hidden iridescent blue cave filled with air that tests your equalizing by pressurizing every time a swell forces it way in.

On the 3rd afternoon, when all equalization cobwebs had been blown away and the stress of London life was but a passing thought, we came to a secluded beach frequented by only a few ships in the winter as it offered sheltered anchoring and more importantly a makeshift barbecue pit on the beach. The water was insanely flat which allowed us to spot “A ladder which we should avoid tangling our anchor on”. Due to the water being gin clear, we could see that this “ladder” was a strange looking wreck that required further exploration. It turned out to be the wreck of a 40 – 45ft yacht, unmarked on charts or diving maps. The steel frame was in one piece, with the wooden shroud all but completely rotten away leaving an almost perfect freedive wreck sitting at 20 – 25m. After the morning rope session on a deserted island and a few excited dives on our new favorite wreck, we needed to find a port.

After a night dreaming of wreck diving, we came back and as the yacht was expertly moored almost directly above “The Unnamed Wreck”, we set up the sled and started diving. We take our travel sled with us most places we go and have done since the early 2000’s when we invented it. A simple machine that uses the scuba tank as the mainstay, to which the weights and lift bag are connected with climbing slings. The secret of this is the way it falls, as in the tank “wants” to fall at an angle, which means – if you let it – it actually sinks perfectly straight not requiring the rope to guide it at all. Resulting in a freefall Guillaume Nery would be envious of.

Almost immediately we found the sheltered bay had virtually zero current allowing unprecedented ability to arrive directly on the wreck every dive. Some of the guests were at their limit as we touched down but, of course, having had a free ride were able to stay and enjoy the awe-inspiring view for a few seconds before returning ‘a la’ sled.

Marco (my assistant instructor) had recently discovered the joys of photography over spearfishing and was intrigued with the idea of photographing the wreck – while using the sled. A seemingly benign proposition considering he had descended to it at least 10 times during the session under his own propulsion, but the proposition of holding both the sled and the camera whilst equalizing was a step too far. The obvious solution – a camera caddy. Elias obligingly took the job of diving to the wreck with the camera, Mika drove the sled and Marco went along for the ride. SIMPLE. Well – simplish. As we needed 3 safety divers as well, the total of 6 divers that needed to be co-ordinated was a point of mirth – but ultimately successful. A demonstration that we can set our own targets, irrespective of what would be considered a difficult dive by other people. 2hours and 30 dives later we clambered back on board to a delightful veggie/vegan brunch that would make London restauranteurs jealous.

The sled is a reasonably new invention, brought about by Jaques Mayol’s desire to maintain the world record. It’s forerunner, by several hundred years, was the skandolapetra. A tool used by Greek fishermen to harvest the ocean floor long before underwater breathing apparatus. A large stone was held by the diver, attached to a rope that was fed out (and hauled back in) by a partner onboard a boat. The EYSailing guys were very excited about the new skandolapetra they had on board, and we wanted to try this ancient Freediving system out. The principle is simple, jump overboard holding a heavy stone, get pulled back when you’re done. The reality is not quite as simple, especially if you are not able to use a noseclip to equalize as the Ancient Greeks were not. We were, however, able to test the new TiTAN titanium nose clip. After an hour of photo shoots, dives and dubious “pull me back” rope signals we were getting a bit cold and ready for a call into port for an evening on land.

Finding depth is not a problem in the Ionian Islands, more often than not the shores drop off into deep iridescent blue, inviting rope sessions at every location. We resisted the temptation in favor of exploration most afternoons, leaving the AM dives open for rope sessions. This was not the only objective of the trip… a more sinister (some would say sinister, I would say “playful”) objective had been given to us. Mermaid photos. Merfolk would be a better description… either way we had to photograph them!

I had some ideas beyond the basic “Merman on a rock” – which involved the interaction of Merfolk and Freedivers. instantly the complexity of these shots became a problem for us to play with and eventually solve. There’s not a lot more I can say – except: we did it. And had fun doing it.

The final part of the trip involved accessing some caves we had previously explored on Kefalonia. We moored off the coast on the last day before returning to the airport, and jumped on the tender for the short trip to the beach to the bemusement of the locals… a group of freedivers coming off a boat – onshore – to dive? We opted to dive the easier of the caves and attempt to photograph our exploration in 360 panoramas. This required a little invention to float the camera exactly 1/2 way out of the water, to which a chip shop polystyrene tray came into its own! Not very technical, but very effective.

3 of us were returning – excited by the prospect of diving in the most amazing location I have ever dived, 3 of us were apprehensive about the prospect of pitch black cave with vertigo-inducing clear water. It did not disappoint. Awe-inspiring dive, with some photos actually getting close to capturing the assault on our senses. The entrance to the cave a bright blue, mesmerizing arch at one end… its light dwindling as we moved 10m from it, leaving us totally dependant on our torches (no ordinary torches I might add). The darkness always holds secrets and breathtaking expectations, especially when there are several chambers beyond your torchlight. Although the main chamber is 15m deep, it feels like you are always just 2m from the surface throughout each dive, you feel like you can reach out and touch the ceiling. From the surface looking down, your buddies seem to get smaller, without moving away from you… a very disconcerting experience.

I have written about the caves of Kefalonia in the past, and filmed them, and photographed them – but they never lose their awesomeness. The pure feeling of freedom within the seemingly endless caverns is addictive and seductive. On this trip, the 3 newbies were (as expected) in sensory overload, unable to take in all the information resulting in dives where they failed to see the 10ft high stalactites just 5m from the surface. Returning divers always seem to have a calm acceptance of what they are experiencing, and a soft focus on what they want to do/see. This trip was not an exception. It was, however, exceptional.

As we walked along the beach back to the tender we reminisced about the amazing trip we had just experienced. 6 days of exploration, crystal clear water, caves, photography, sled diving, drone flying and good times – not forgetting Mermaids and Mermen.
Facilities Overview

I was pleasantly surprised to find although it was a “small” yacht with only 8 beds, how the set-up maximized space, and we never felt cramped. The showers in the 2 “heads” (ships loos) were awkward but with a hot fresh water shower on the rear of the boat, these hardly seemed necessary.

I can’t speak highly enough of the crew, Elias (Skipper) was insanely knowledgeable and helpful beyond any expectations, Panos (host) became so in tune with our requirements the merest thought of tea or light lunch was enough to bring it into existence. The presence of a vegan, a veggie and recovering caffeine addict was not the slightest problem with them.

They have a standard Freedive Bouy onboard, with enough rope to dive deep. Of course, they stipulate that the depths they offer a group depend entirely on skill levels and qualifications. Oxygen is available on the islands, but again is the responsibility of the group.


By freedivinguae

Facts about Freediving and its amazing records!

Since Dahab is one of the world´s main spots for freediving, almost every day I see freedivers around here practicing their skills (if I actually just look to my right now, I can see three different floating devices around 30-40m offshore). I am totally astonished by their abilities of holding their breath, relaxing to a point where the heart beat slows down to less then ten beats per minute and controlling their mind. I watched dozens of videos and just cannot be anything else than fascinated.

Freediving or Apnea (the Greek word a-pnoia literally means “without breathing”) is based on a subconsciousness reflex (mammalian diving reflex): As soon as cold water encloses our face, the body shifts its bloodstream from the extremities into the brain and heart and slows the heart beat down. The body does so attempting to keep the most vital functions alive and concentrates the flow of oxygen into the heart & brain. This effect has been studied in dolphins, seals and other mammals. The deeper the dive, the stronger it gets. After years of training freedivers are able to calm themselves down using various breathing techniques and achieving a state of general fitness. So freediving is a lot about relaxation and very mental, as one has to learn to deal with the urge to breath to extend the dive.

The history dates back several thousand years. Humans are believed to have been freediving a long time in search for sponges, fish & shells making freediving most probably one the most ancient sports of them all. A great myth tells the story of a sponge diver recovering an anchor of a Italian ship in front of an island in Greece. In 1913 the ship lost its anchor and asked one of the best spongedivers in this area to recover it. This guy was named Chatzistathis or Haggi Statti, was about 1,70m in heights and weighed around 65kg. The legend says he recovered the anchor from 88m depth, holding his breath for about three minutes. He used a primitive technique, Greeks have been using as long as their civilization exists: the so called “Skandalopetra”. A round stone with holes for the fingers, almost used like a steering wheal of a car enabling the driver (or diver) to change directions while diving down headfirst (!). According to the story, he was rewarded a little amount of money and the permission to fish with explosives.


Whether its a myth or not, fact is that nowadays freedivers have gone much deeper than this. From the 1950s on freediver constantly broke their records and achieved greater depths on one single breath. Today there are two major organization, the CMAS (The World Underwater Federation) founded in 1958 and the AIDA (Association Internationale pour le Développement de l’Apnée) founded in 1990. There are many different disciplines within the competitive freedive sport, some of them only recognized by AIDA, others by CMAS and some by both. Here are some examples:

Static Apnea

Usually this discipline is practiced in a pool and aims to hold the breath as long as possible. The current world record recognized by AIDA lies at 11min and 35s, hold by Stéphan Mifsud since 08.06.2009.

Constant weight Apnea

This discipline is about deepdiving. It is not allowed though to drop any weights during the dive and fins (either mono or bi) can be used. The current world record (AIDA) lies at 128m achieved by Alexey Molchanow on the 19.09.2013.

Constant weight Apnea without fins

Basically the same like above just without any use of fins. The current AIDA world record holder William Trubridge achieved an incredible depth of 101m on the 16.12.2010.

Free immersion Apnea

In this discipline divers use a vertical guiderope to pull themselves down and up again without dropping weights during the dive. Again William Trubridge holds the current world record (AIDA) with 121m since the 04.10.2011.

Variable weight Apnea

Divers use a weighted sled to descend and ascend by using fins or pulling themselves up a line. William Trubridge holds the world record (AIDA) of this discipline as well with 145m. He achieved this depth on the 03.09.2013.

No Limits Apnea

This discipline allows all kind of equipment to dive as deep as possible. Usually a weighted sled is used to descend and an inflatable device to ascend again. Herbert Nitsch holds the world record (AIDA) with an incredible 214m since the 14.06.2007.

One doesn´t have to aim that high in order to practice freediving and enjoy it. There a various freedive centers offering training from beginners to more advanced freedivers. The ones I´ve looked into either offer a training by SSI or by AIDA . By being able to hold your breath for as long as possible and equalizing properly to achieve greater depths, people will encounter completely new experiences of diving. Fish and other marine inhabitants are not as disturbed from noise of bubbles and breathing, allowing you to get a much closer look than they most probably would have granted you while scuba diving. Therefore, underwater photographers might want to improve their freediving 😉 Just the other day I had a nice encounter myself: I was practicing a bit and saw some squids below me in around 7 m depths or so. I slowly pulled myself down the rope and gently swam towards then. They are usually very shy but let me get quite close before they opened the line formation only a bit (I don´t know why, but I´ve usually seen them like this) and let me swim through them – Awesome!

People have been freediving and spearfishing for a long time and still today there are many people practicing it (though I do not support this, as I rather see all kinds of fish swimming than on a plate..). I just started recently with some easy exercises here in front of Bannerfish bay and I really love it and hope to be able to do a course soon or at least before I leave beautiful Dahab.. My girlfriend and me had a day with freedive Instructor Brian Crossland almost two months ago now, but this course was rather targeted at improving the breathing in general for scuba diving in order to achieve longer dive times. Nevertheless we gained some very interesting knowledge which I try to apply now.

There are some dangers in freediving, that shouldn´t be forgotten to mention. One doesn´t have to dive 100m deep to encounter them. A shallow water blackout can happen to anyone, whether experienced or not. There is no warning system or whatsoever prior to blacking out. The only warning system we have concern the carbon dioxide level in our blood. CO2 is a waste product of normal breathing, when oxygen is being metabolized. If the concentrations reaches a certain point, we feel the urge to breath. Hyperventilation causes the CO2 level to drop, extending the time until the urge to breath kicks in. It cannot saturate the blood more though, as the normal breathing rate the body dictates already achieves a saturation of oxygen of around 98-99%. Hyperventilation can become dangerous and lead to blackouts as the trigger is not reached before the oxygen level is already very low. The following diagram demonstrates this:

If consciousness is lost, drowning may appear. Therefore it is very important, that you always dive and train with a buddy. If you dive without a buddy, no matter how deep, and a shallow water blackout occurs, you are likely do drown. By now there are thousands of active freedivers around the world, and every year a number of them dies. There are no statistics about this, but most likely a couple of dozens loose their lives while freediving.

Another potential dangers is the squeeze of your eardrums and finally their explosion. The deeper you go, the higher the water pressure gets pushing your eardrums in. There are several equalization techniques, but if you don´t know how to to them, it can get very painful and worst case scenario is that you can lost your ability to hear or suffer from ear problems for the rest of your life. Obviously this danger increases the deeper you go. Beginners are not likely to encounter severe problems (if they don´t push it without proper training).

There are many other dangers concerning freediving, especially the competitive deep diving. If you are interested in knowing more about these, I´d recommend some more reading on this.


By freedivinguae

Scores of Dolphin Deaths Have Scientists Baffled

Though the dolphin die-off has be attributed to a virus, the cause of the disease remains a mystery.

Since late last year, four or five dolphin carcasses have beached in Brazil each day. Scientists have confirmed that a virus is to blame, but the mortalities still have conservationists baffled.

The Associated Press reports more than 130 gray dolphins have washed up in the Bay of Sepetiba, a coastal area about 45 miles west of Rio de Janeiro, since late November. Another 40 dolphin carcasses were found on the neighboring island of Ilha Grande. Combined, that’s more than 20 percent of the area’s known dolphin population, which, at an estimated 800, may be the highest concentration of the species in the world.

Local conservation NGOs like the Boto Cinza Institute and SOS Botos have examined the carcasses’ skin, blood, and bones under the suspicion that a bacterium or virus was to blame. The School of Oceanography at the State University of Rio de Janeiro confirmed that cetacean morbillivirus, which can infect dolphins, porpoises, and whales, killed the marine mammals.

But scientists aren’t sure what caused the outbreak, or how long it might last. They are still trying to determine other reasons for the dolphin die-off.

The virus attacks the animals’ immune systems, resulting in skin lesions, pneumonia, and different types of infections. Boto Cinza Institute chief coordinator Leonardo Flach told StoryTrender in early January that if a pathogen-related disease was diagnosed, 70 to 80 percent of the population could die. Cetacean mirbillivirus can spread between animals through inhalation or contact. Often living in pods of up to 200 individuals, dolphins have close relationships, and a contagious illness could be devastating.


By freedivinguae

Could machine learning save this sea cow?

It’s hard to imagine this adorable sea cow getting caught in a fishing net, or losing its home to coastal development. Unfortunately that’s what’s happening to many populations of large marine mammals around the world. It’s urgent—sea cows are under threat of extinction.

Sea cows might be cute, but it turns out they’re also really hard to keep track of. And keeping accurate data on populations is critical for conservation efforts.

For decades, scientists had to spend days peering out of small planes to count populations, which was expensive and sometimes hazardous. Dr. Amanda Hodgson of Murdoch University has helped to change that, using drones to take aerial photography of the ocean. But now that they can collect aerial photos remotely, there’s a new challenge: how can they find the sea cows in 45,000 photos?

Try it yourself—look for the sea cow in this image, which you can click to get in full resolution:

Can’t find it? Hint: it’s in the middle of the lower-left quarter. Yes, that little gray smaller-than-fingernail-sized sliver. To see where it is, check out the image with the sea cow circled

Now, what if you had to do this manually on tens of thousands of images? It would really slow down research, and it wouldn’t scale to other regions and other species of sea mammals.

So Dr. Hodgson and team decided to apply a little magic: machine learning. She teamed up with Dr. Frederic Maire, a computer scientist at Queensland University of Technology. Using TensorFlow, the free open source machine learning platform that’s now been out for exactly one year, they built a detector that could learn to find sea cows in these photos automatically. (It’s a little like the image recognition that lets you search Google Photos for shots of particular dog species, or sunsets, or whatnot—but much more specialized for this scientific task.)

The results are encouraging: an early version of their detector could find 80% of the sea cows they’d found manually in images, and they expect to improve performance over time. This suggests the approach may scale well—not only for sea cows, but for other sea mammals such as humpback whales and certain dolphins as well. Eventually if they’re able to track these threatened populations on a large scale, conservationists have a much better shot at knowing how they’re impacted by human activities, and where it’s most urgent we protect their habitats. In a small way, machine learning might help save the humble sea cow


By freedivinguae

Whale Allegedly Protects Diver From Shark, But Questions Remain

For 28 years, Nan Hauser has been researching and diving with whales. The biologist is the president and director of the Center for Cetacean Research and Conservation, a group that has researched everything from the population status to feeding behaviors of these animals.

But during a trip to look at whales in the Cook Islands in the South Pacific last September, Hauser says she had an encounter unlike any she had experienced before.

A humpback whale, a marine mammal capable of weighing 40 tons and growing 60 feet long, swam toward Hauser. For ten minutes, it nudged her forward with its closed mouth, tucked her under its pectoral fin, and even maneuvered her out of the water with its back.

At the time, Hauser was frightened by the encounter and unsure of what to do and what the whale was intending.

“I was prepared to lose my life,” she says. “I thought he was going to hit me and break my bones.”

In addition to conducting research, Hauser says she was also in the Cook Islands to work on a nature film, so at the time the whale approached, both she and a fellow diver were armed with cameras. Hauser’s point-of-view footage shows just how persistently the whale nudged her. A second whale can also be seen lurking just behind the first.

When she finally made it out of the water and up onto her boat—bruised and scratched from the barnacles on the whale—Hauser saw a third tail moving from side-to-side.

“I knew that was a tiger shark,” she says.


By freedivinguae

Understanding the Impact of Deep Diving

“How deep have you been underwater?” was a question asked by one of my open water course. This is a tricky question, one that I don’t like to answer because I fear that my students may aspire to my maximum depth, or worse, attempt to beat it. A more appropriate question is, “How deep should scuba divers descend?” Unfortunately, the answer is not straightforward–it depends on a variety of factors such as breathing gas, experience level and personal tolerance for high partial pressures of inert gasses and oxygen.
What Is the Deepest a Scuba Diver Has Descended?

The current depth record for open-circuit scuba diving is held by Ahmed Gabr, who descended to 332.35 meters (1,044 ft.) on September 18, 2014.
More Importantly, How Deep Can You Dive?

Most recreational scuba diving organizations set the maximum depth for a certified, experienced recreational divers breathing air at 130 feet. Divers should heed this guideline. The fact that extremely experienced, technical divers have descended beyond 1000 feet on admittedly risky dives does not mean that recreational divers have any business breaking suggested depth limits. When a diver considers the reasons behind established depth limits, it becomes obvious why breaking depth guidelines is foolish.
Considerations in Determining a Maximum Depth

Decompression Status
The deeper a diver descends, the shorter his no-decompression limit will be. For example, a diver who descends to 40 feet can remain at the depth for 140 minutes (air supply permitting). A diver who descends to 130 feet can stay only 10 minutes at that depth before accumulating so much nitrogen in his body that he requires a series of decompression stops on the way up to reduce his risk of decompression sickness. Descending beyond 130 feet without decompression dive training does not allow a diver much time to enjoy his dive.

Air Consumption
A diver breathes air at the pressure of the water around him (ambient pressure). The deeper a diver goes, the more the air he breathes compresses (learn more about water pressure and diving). At a depth of 130 feet, a diver consumes his air approximately five times faster than he does on the surface. Divers who plan on diving to this depth will find that their dive time is limited by air consumption. Not only will a diver use his air more quickly at greater depths, he will also require a large air reserve for the long ascent from deep dives.

Some gases, such a nitrogen, may cause narcosis in divers at increased partial pressures. Every diver will experience this narcosis eventually, but the onset of inert gas narcosis varies from diver to diver and from day to day. Be warned–even if you experience the drunken feeling of narcosis as enjoyable, it shares many of the symptoms of alcohol intoxication such as impairment to motor coordination, judgment, and reasoning. Some divers even report visual disturbances and a skewed sense of time.

This is not a good state to be in when deep underwater. A diver should slowly increase dive depths as he gains experience and he should be sure to make his initial deep dives (deeper than 60 ft.) with a qualified individual, such as a guide or instructor who can monitor him for signs of narcosis and assist him if necessary.
Oxygen Toxicity
At very high concentrations, oxygen becomes poisonous (oxygen toxicity), causing convulsions, unconsciousness and even death. When the recreational depth guidelines are followed, oxygen toxicity is not a concern for scuba divers. Still, this gives divers another very good reason not to exceed depth limitations. The oxygen in air may become toxic at depths beginning at approximately 218 feet, and gas mixtures with high percentages of oxygen, such as enriched air nitrox, may be toxic at much shallower depths.

Experience Level
Depth is a stress factor in scuba diving. Psychologically, deeper dives are stressful because divers are farther from their exit point. Divers will notice their air supply dropping more rapidly than at shallower depths, may notice an increase in breathing resistance and are likely to experience some form of mild narcosis. While deeper dives are frequently very beautiful, have pristine reefs, and different wildlife than shallow dives, divers should increase their dive depths cautiously. Making your first deep dives under the supervision of a qualified guide or instructor is always advisable.

What Are Common Depth Limits for Recreational Certification Levels?:

The suggested depth guidelines for various recreational scuba diving certifications vary among organizations. In general:


Experience Courses (e.g. PADI’s Discover Scuba Diving)–40 ft. (12 meters)
Subsequent Dives for Non-Certified Divers–40 ft. (12 meters)
First and Second Training Dives–40 ft. (12 meters)
Dives 3 and 4 of Open Water Training–60 ft. (18 meters)
Open Water Certified Divers–60 ft. (18 meters)
Experienced Certified Divers, or Divers With Advanced/ Deep Training–130 ft. (40 meters)


Children Ages 8 – 9 (First Dive)–6 ft. (2 meters)
Children Ages 8 – 9 (Successive Training Dives)–2 ft. (4 meters)
Children Ages 10 -11 (Open Water Certified)–40 ft. (12 meters)


Teenagers Ages 12 – 14 (Open Water Certified)–60 ft. (18 meters)
Teenagers Ages 12 – 14 (Advanced Certifications)–70 ft. (21 meters)
Teenagers Ages 15 and Over–Same as adult limitations