Category Archives: Freediving tips

5 Simple tricks for cold water diving

This post was submitted by Luca Malaguti. Luca dove with a 3 mm suit in the cold water of the Pacific for the longest time. In this article he shares some tricks to stay warm.

The Canadian Pacific Northwest is a stunning place for scuba diving, freediving or snorkeling. It offers some of the cleanest waters in the world, fantastic underwater landscapes and unbelievable marine wildlife. The only issue for many people that wish to take part in these activities around Vancouver, the Gulf Islands or Victoria, is that for most of the year the water is quite cold.In the summertime, the Howe Sound can have surface water temperatures that range between 14 to 20 degrees Celsius. However, it’s always cold below the thermocline.

Continue reading 5 Simple tricks for cold water diving

Breathe better and deeper: increase lung volume with these exercises

So you want to increase lung volume? There are several ways to do this, but you should probably start with becoming a better breather. That means, you should be able to fill up the entire volume of your lungs with a deep inhale before you actively start to do exercises that will increase lung volume.

Let me show you what I mean.

Active breathing vs. passive breathing

Most people go through life without taking active control of their breathing. The autonomous nervous system takes over the act of breathing if you don’t think about it, which means that you don’t have to think about it…

And that means that most of us never think about breathing.

The body responds to simple stimuli that will increase or decrease the breathing rate. For example, the breathing rate will increase if CO2 in the body increases or if the temperature decreases.

The body does not optimize each breath. If you are relatively untrained your inhales could be short and you may be using less than 75% of your vital capacity for each breath.

Optimizing the respiratory system is something we have to do by consciously using it. In other words, you need to become aware of your breathing, and consciously change the way you breathe.

Get your shoulders out of the way first

But first, let’s become somewhat aware of what our posture does to our breathing. The shoulders are only attached to the rest of the skeleton by the collar bone. Because of that, a substantial weight pushes down on the widest part of the rib cage: the weight of your shoulders and arms combined.

Don’t believe me? Then try this:

  1. Stand up or sit up straight with your arms hanging down the side of your body. Breathe in as deep as you can.
  2. Stand up or sit up straight with your hands on your hips and your elbows out. Breathe in as deep as you can.

If you noticed it was easier to breathe in that second time, you felt what I am talking about.If you did not you are either a blessed freak of nature or you are hardly using your upper intercostal muscles.

Funny side note. Opera singers have their arms wide and in front of them when they sing a strong note for a reason: it opens the chest.

In order to loosen up the shoulders:

  1. Stretch arms out overhead, and in a wide arc let the left arm come underneath the right. Clasp your hands together (as best you can). Hold for one minute and then switch sides. This is part of the yoga ‘eagle pose‘.
  2. Put your hands on your glutes, fingers pointing down look forward and up so that your spine is slightly arced back. Try to gently move the elbows closer to each other behind your back. You should feel a stretch in your front shoulders.

This simple preparation goes a long way. It won’t help you actively increase lung volume yet but it will allow you to get the most out of your breathing later. There are many more ways to open the chest with stretches but let’s move on to the actual breathing.

Three simple breathing exercises

increase lung volume
Trust me, my hamstrings are probably tighter than yours (it’s not me in that photo). I grow tired of the classic shot of a beautiful person doing supposedly peaceful meditation on an empty beach while the sun sets, in a position that 99% of humanity will never experience. The truth is that you can meditate anywhere, in any position. For breathing exercises, all you need to make sure of is that you have a straight back (this person seems to be a bit crooked, but it might just be the baggy t-shirt). You can sit cross legged, on a couch or chair, or stand up straight.

Audible inhales

One of the best ways to actively increase your lung volume is by limiting the flow of air through your throat and training yourself to keep that flow constant. Try it:

  • Keep one hand on your belly, and one on your chest.
  • Inhale slowly and constrict your throat slightly so that your inhale is audible (another way to inhale audibly is to make a whistling sound with the lips).
  • Focus on the belly first. Your lower hand should be moving outward.
  • Keep the sound of your breath constant.
  • Once it becomes difficult to keep that lower hand moving out, your chest should start to inflate. Try to keep the lower hand outwards as much as you can and continue with inflating the chest. Exhale slowly and repeat.

Alternate nostril breathing

Alternate nostril breathing is a similar exercise but additionally clears your nasal cavities. The exercise is fairly straightforward.

  • Sit with a straight back and close your right nostril with your right thumb. Inhale fully and slowly through the left nostril.
  • At the top of your inhale, pause and release your right thumb. Close the left nostril with the ring finger of the same hand.
  • Exhale fully and slowly through the right nostril, and then inhale fully and slowly. Pause and close the right nostril.

End range of motion exercise

When I was recovering from a rotator cuff injury I was given an exercise to work on the power and strength at the end of my range of motion. It was an easy exercise and I realized it could be done with intercostal muscles as well. I believe that out of the three exercises here this one will give you the fastest results.

  • Sit with a straight back
  • Put your hand on your hips (so the shoulders don’t weigh down the ribcage)
  • Inhale slowly and fully
  • Once you are at the max inhale, use your diaphragm and intercostals to keep it at the max.
  • Do not lock the throat or mouth. The air should be able to move freely from your mouth into your lungs, and you need to use your respiratory muscles to keep it in the lungs
  • Exhale after 10 seconds
  • repeat 5 times

How long should you exercise? Just remember that five minutes per day beats one hour once per month.

Forget about packing for now

Packing, or over-inflation of the lungs, is a simple tool that can increase lung volume directly and dramatically. However, because it is a passive tool it works against the resistance of the rib cage. The over-pressure in the lungs has caused embolisms resulting in partial paralysis, and a range of other serious injuries in freedivers on land and in the pool. It should be avoided for anything but dives that are well below residual volume. From AIDA’s Facebook announcements:

“Recently several packing related incidents with lung damage and/or transient neurological symptoms have been reported. Keep in mind that lung packing and pack stretching are very advanced techniques that may lead to serious medical conditions and even death. Packing should be performed with care and is something that we do not recommend in the AIDA education program”

Packing alone is not worth your time. Breathing exercises are always good, both to increase lung volume and better breathing overall. Once you are going to push the numbers during very deep dives packing is something you may want to consider. If you are interested in more info, Walter Johnson has a great article on packing on his website Freediving Solutions.

When and how many exercises should I do?

Great question. When considering how much time to put in any exercise remember that consistency and moderation are the long term winners. Five minutes per day will increase lung volume, but one hour on one day per month is not going to do much for you. The best time to do these exercises is right in the morning, so you can reap the benefits all day.


Spitting blood after freediving: squeezes and squeeze-like symptoms

You might have come up from a dive and coughed up some foamy pink mucus, or some phlegm with blotches of blood in it. Chances are that you experienced a squeeze. We will discuss the causes for squeezes and squeeze like symptoms in this article. If at some point you were spitting blood after freediving and wondered what was going in, keep on reading.

As usual, remember that I am not a doctor. The symptom of spitting or coughing up blood is called hemoptysis and can have numerous (potentially life-threatening causes). If in doubt, see a doctor.

True squeezes

Squeezes happen when the negative pressure on the lungs or trachea is too much for the tissue to handle. Squeezes commonly do not occur unless you reach residual lung volume. Residual lung volume is reached between 25 and 45 meters for most divers, depending on how big the inhalation was and if the diver packed or not. A squeeze may occur at shallower depth if you have bad posture, or if you have heavy contractions.

Trachea squeeze

The trachea squeeze might be the most common squeeze type. The trachea is the least compliant to pressure changes. It is essentially a tube reinforced with cartilage rings. These cartilage rings don’t stretch very well and keep the trachea open, even if you would rather have it collapse. Blood vessels along the wall of the trachea can rupture if the negative pressure becomes too high.

Phlegm from the trachea looks white, transparent colourless, or transparent yellowish (opaque yellow or green if you have an infection), and will contain blotches or strings of blood if you have a squeezed trachea.

spitting blood after freediving
Find the trachea, lungs and alveoli here.

Lung squeeze

The lungs are soft spongy organs that stretch and compress better than the trachea, but unfortunately they can still get squeezed. If the lungs are subject to negative pressure, yellow fluid can start to leak into the lungs from the alveolar capillaries. Although this is not diagnostic of a squeeze, it does mean that you are descending to depths at which you may be at risk.

If the negative pressure increases, capillaries in the lungs may start to rupture, causing blood to fill the alveoli. This is called a lung squeeze.  If you have suffered a lung squeeze you will cough up pink foamy mucus.

What do you do after a squeeze?

There are no set guidelines for how to deal with squeezes. Most teaching organizations will state you need to be medically cleared for diving by a specialized doctor. Although I agree, my guess is that most divers do not follow this mandate.

Another recommendation that I have seen is as follows:

If your sputum (sputum = what you cough up) contains less than 50% blood, take one week off diving. If your sputum contains more than 50% blood, take two weeks off diving. If you only cough up blood, seek medical attention as soon as possible.

This is a more conservative approach:

If you see less than 25% of blood in your sputum, take one week off diving. If you see 25 – 50% of blood in your sputum, take two weeks off diving. Seek medical attention if:

  • You see more than 50% blood in the sputum
  • You cough up fresh blood more than 12 hours after the dive
  • Other symptoms such as pain or tightness in the chest are severe
  • Any symptoms persist for more than 5 days
  • SaO2 is <95% more than 15 minutes after the dive

Note that the symptoms will probably be gone within a day or two. This does not mean you can go back to diving again. The damaged tissue will likely still be weak and you should give it ample time to heal.

Protecting yourself against squeezes

  • Technique

To avoid getting squeezed, practice your technique at maximum 20 meters depth. Until you can do a dive with perfect posture (including the turn), do not dive deeper.

  • Stretching

Intercostal and diaphragm stretches will help increase the flexibility of the ribcage, and protect yourself against squeezes. In Pre-Dive Preparation, Sara Campbell teaches excellent stretching routines.

  • Gradual adaptation

Your body protects the trachea and lungs by blood shift, an effect of the diving reflex. Your adaptation to depth should be gradual to allow your body to get used to the depth and the required blood shift. In Holistic Freediving, Eric Fattah shares methods of training the dive reflex.

Not all squeezes are squeezes?

From April 2016 onwards, I started getting squeeze like symptoms on dives shallower than 25 m. These dives were well in my comfort zone, my average leisure dive was about 20 – 30 m. I would come up and cough up bloody sputum, indicative of a trachea squeeze. One time, the issue seemed to start 5 minutes after my last dive.

I took a week rest every time it happened and started more serious stretching of the lungs and trachea, to no avail. After I got back to diving, it was only a matter of time before the next ‘squeeze’.

It took me a while to figure out what was going on.

The ‘squeezes’ started after I moved to a busy intersection, with poor air quality. During that time, I had more colds, and often had an aggravated throat. I was more ‘phlegmy’ to start with. After I realized that the ‘squeezes’ started after I moved places, I bought a HEPA (high efficiency particulate absolute) filter and put it in the bedroom.

End of story.

Since I have started using a HEPA filter I have not once had squeeze like symptoms despite diving deeper, I’ve had better sleeps, and less colds. Starting your dive with an aggravated throat greatly increases the chances that you burst a blood vessel in the throat. Poor equalization technique probably increases the risk. Although the symptoms are the same as those of a trachea squeeze, these are not squeezes. They may occur simply when you clear your throat at the surface after a dive.

Immersion pulmonary edema

A phenomenon that results in similar symptoms (to those after squeezes) is called immersion pulmonary edema (IPE). This is a leakage of fluid from the bloodstream into the lungs. It has been reported in triathletes, swimmers, U.S. navy SEALs and scuba divers. You can read more about IPE on the website of DAN (Divers Alert Network). Although IPE may be somehow related to squeezes, the cause is likely different from negative pressure induced edemas.

Please share your experience in the comments.

Breathe up time: the key to relaxing dives

How long should your breathe up really be? When you surface from a dive, your body needs to replenish its oxygen stores and high energy phosphates. The body also needs to get rid of the excess CO2 and other waste products such as lactate. Once that is done, or perhaps at the same time, you need to start relaxing for the following dive. But how long does it take? A minute? Ten minutes? Let’s find out.

This article is not about decompression sickness, which I will cover in another article. 

Oxygenating the blood

For an average Joe with 70 kg body mass, 5 liters of blood and a heart stroke volume of 70 ml, the blood is pumped around completely in 71 strokes (5000 ml of blood divided by 70 ml = 71). Based on the assumptions that 1) his heart rate rises to about 110 immediately after a dive and drops after a minute, and 2) the lungs fully oxygenate all blood that passes by, he should have fully oxygenated blood within 39 seconds.

After 39 seconds, your blood is fully oxygenated.

If you have ever done 2 dives with only a 39 second breathe up in between, you know that this is not the full story. The body is not yet back to steady state within 39 seconds, so let’s continue exploring this topic.

High energy phosphates

You may have read my articles on muscle metabolism and muscle fiber. If you have, and you were not abysmally bored, you may remember the ‘high-energy phosphates’ or ATP-CP. If you did fall asleep on your keyboard while reading here is a one sentence recap: ‘High energy phosphates in muscles can provide energy for about 10-15 seconds of maximal muscle contraction and do so without costing O2 or producing CO2’. But how long does it take to replenish these high energy phosphates after a dive?

Up to 70% of CP is resynthesized in 15 seconds. If you are severely vasoconstricted because of cold or the dive reflex it may take somewhat longer. The remaining 30% will be resynthesized after roughly 2:45 minutes, so you need about 3 minutes in total to replenish high energy phosphates.

After 3 minutes, your high energy phosphates are replenished.

Excess CO2

And what about the stuff we need to get rid of after a dive? How long does it take to vent off all that excess CO2? Available data for the recovery of Steller sea lions suggest long recovery times (large variations between individuals are common). These recovery times are based on VCO2, the exhaled carbon dioxide after a dive.

For a dive of 3 minutes, VCO2 takes approximately 5:30 to recover, and for a dive of 2 minutes we can expect a 4-minute recovery time. The reason CO2 levels take a long time to return to normal is that CO2 is transported throughout the bodies tissues, and it takes time for the CO2 to make its way back into the bloodstream and to the lungs.

breathe up
As usual there is more data available of diving mammals than of humans. This is a grey seal.

Of course, we are not Steller sea lions. Steller sea lions are much larger and adults can weigh over 1000 kg (2200 lbs), and have lung volumes that are proportionally larger than those of humans. But does that mean that they lose CO2 faster or slower than us? My guess is that because of our size we lose CO2 at the same rate or perhaps somewhat faster than Steller sea lions, but I can’t prove it.

The release of CO2? Unknown, but likely less than 4 minutes for a 2-minute dive.


Now I did talk about lactate earlier. As it turns out it takes about an hour for lactate levels to return to normal after heavy exercise (or a dive during which you feel significant leg burn). This recovery time can be reduced to about 50 minutes if you go jog or go for an easy bike ride.

I wouldn’t wait for it if I were you. A better solution would be to not dive to exertion, so you will have a longer dive session. Lactate is only produced in significant quantities once your muscles become hypoxic. You can feel it as leg burn towards the end of your dives.

Lactate? Don’t wait for it…

In conclusion, if you want to make long and comfortable dives your breathe up should be at the very least 3 minutes, so that your high energy phosphates are fully recharged. Better still, take 4 minutes in between dives so that your CO2 levels are back to normal. Of course, during the breathe up, and especially the last 2 minutes you should try to be completely still.

And another method is to not overthink it and just do what feels right… But that would not make for very interesting articles. Let us know what your approach is below!

Preventing and dealing with ear infections after freediving

I have had recurring ear infections since I started freediving. At first I would only get them after pool training, but later I also started getting them after ocean dives. I am unfortunately very prone to ear infections because of a narrow ear canal that makes it hard to drain my ears. For me, the war on germs is a necessary post-dive ritual.

This article is based on my and other freedivers’ experiences, but remember that I am not a doctor – if you have health concerns, do not rely on me for advice.

Symptoms of an ear infection after freediving

An ear infection is caused by bacteria in the outer ear. If water remains in the outer ear after a dive these bacteria can multiply and cause an infection. Usually these infections become apparent the day after the dive, gradually increase in severity, and then decrease again. During an ear infection you may experience some difficulty hearing through the ear affected, swelling of the lymph nodes in the neck (more prominent on the side of the ear infection) and headaches.

If you experience sudden pain in your ear during a dive, it’s not an ear infection but barotrauma. If you do not have an ear infection but another ear problem you may injure yourself further by using the methods below, so make sure you know what is causing you grief!

Prevention of ear infections

  • Rinse your ear with a natural oil (olive oil, coconut oil) prior to diving

Ear wax is a substance composed of oils and dead skin and is called cerumen. It protects the skin of your ear canal. By rinsing the ear with a natural oil prior to the dive session you reinforce the cerumen and make it less likely that germs or harmful substances make contact with the ear canal. I myself have not used this method but after the initial publication of this article, other freedivers mentioned this as a good prevention technique.

  • Drain your ears after every freediving session

The first thing to do once you come out of the water is to make sure you have drained all the water out of your ear. The water that remains in your ear, together with some ear wax and things that float in the water such as algae, are the perfect substrate for bacteria to grow and multiply on. Drain your ears thoroughly and you stand a much better chance of avoiding an ear infection in the first place.

  • Use a a solution with vinegar and/or alcohol once after freediving

If you are prone to ear infections like me, just draining your ears won’t work. Time to take out the bigger guns so that you do not give bacteria a chance. I use a 50% vinegar, 50% alcohol solution in my ears after dives. If I do this right away after a dive, I know I won’t get an ear infection. You can get rubbing alcohol from the pharmacy, and buy simple white vinegar at the grocery store. I use a dropper that used to have different ear drops in it to administer it. I keep the solution in my ear for about 5 – 10 seconds and then let it drain.

Ear infection
Simple rubbing alcohol. Mix this 50/50 with white vinegar and put one or two drops in both ears after a freedive, and drain. Works like a charm
ear infection
In case you use a dropper that was originally intended for something else such as an eye dropper, make sure that you label it. Your family or roommates won’t appreciate putting peroxide in their eyes.

Note that alcohol dries the ears. For this reason, some freedivers mix the alchol with coconut oil, or d not use alcohol in the mix. Rather, they choose to use alcohol and water. I am sure there are more out there, but here are some possible concoctions:

  • 33% alcohol, 33% water, 33% vinegar
  • 50% alcohol, 50% vinegar
  • 50% water, 50% vinegar
  • 80% alcohol, 20% coconut oil

If you do get an ear infection

If I forget to use the vinegar-alcohol solution, I stand a fairly big chance of waking up the next day with an ear infection. Here’s what I do if I get an ear infection:

  • Use a vinegar and alcohol solution every 4 hours

If I have a starting ear infection, I use a 50%/50% alcohol-vinegar solution every four hours. I lie down on the couch with the affected ear up, administer some drops and leave them in the ear for about a minute, and then let it drain. I do this every four hours during the day until the infection recedes.

  • Blast the bacteria with hydrogen peroxide

A very effective way to remove ear wax and kill bacteria is hydrogen peroxide. A topical solution of 3% hydrogen peroxide does the trick. Use a dropper to get 3 drops in your ears and let it sit for 5 – 10 minutes until draining. The hydrogen peroxide will liquefy the ear wax and bacteria that cause the infection so that it can drain out of the ear. This method is very effective, but does remove the ear wax, a protective lining that coats the ear canal. I only use hydrogen peroxide if I have excessive ear wax or if the ear infection is severe (excessive ear wax and a severe infection commonly go hand in hand).

Always label your droppers aprropiately!

Ear infection
Hydrogen peroxide. The bugs don’t like it. You ears may not either, but it does get rid of the infection. Don’t make using hydrogen peroxide a habit.
  • Go see a doctor

I commonly notice a result within a day or at least two days using the alcohol-vinegar solution and/or hydrogen peroxide. I recommend you see a doctor if the above methods do not work or if you have a serious infection. Although you can get topical antibiotics over the counter in some countries, I don’t recommend using antibiotics without prescription.

I’d love to hear your method of battling ear infections, let me know what works for you in the comments!

Are all fins created equal?

This post was submitted by Dave Forcucci, a freediver based in Washington State. Dave decided to buy an underwater speedometer and to test freedive fin efficiency. You can read the results of his extensive testing here.

It is difficult to imagine where we would be without the information available from the Internet.  Back in the day when we relied on local dive shops for equipment the availability of freedive gear was very limited.  Fortunately we still ventured underwater.  Now with access to a world of freediving resources, we are able to fine-tune our gear and techniques.  Of course before diving in, a freedive course is essential for safe and informed breath hold diving.

With our freediver course under our belt we are familiar with the different pieces of equipment, which thankfully are not many. This is why we like free diving to begin with.   Now we are ready to go diving.  Well maybe.  You are deciding which mask fits best on your face, which snorkel feels best in your mouth and what flavor fins appeal to you and your budget.  You can ask your dive buddies and your free dive instructor about which they prefer and you will, most likely, get a range of advice.  But equipment is personal and we all choose what we believe will work for us, and like most things in life we make compromises.

freedive fin efficiency
Ready for some rigorous testing

What you should know about freedive fins

In this piece we are only going to consider fins.  And there are lots of choices out there.  But basically you choose either a plastic blade or a composite blade that could be either fiberglass, carbon, or a mixture.  Having a list of requirements is always a good thing before you go cyber shopping.   These requirements are personal choices so I will use myself as an example with the understanding that yours may be very different.  The requirements can be listed in order of priority, depending on who is doing the fin shopping.

A comfortable foot pocket is important and in a perfect world you could try on each brand and go for a swim. In reality we have to guess and hope it fits well.  Next requirement: Blade angle.  I learned from experience that it is easier to swim on the surface with a 20 degree angle or so between the blade and foot pockets.  These days most bi-fin blades are manufactured with an angle but some are not.  Likewise, monofins commonly have an angle between the foot pocket and blade, which is helpful for swmming and gliding.  Unlike bi-fins, monofins typically do not have a bent blade, instead the foot pocket is modified to a 20 degree angle. One monofin manufacturer sells a monofin with a bent blade.  This reduces the weight on your shoulder as you tote your fin to oceans and pools from 4 kg (9lbs) for a monofin with angled foot pockets to less than 2 kg (4.5 lbs) for a monifin with an angled blade.  Which is more efficient in the water is yet to be determined.  Other fin properties you need to think about before you buy are the stiffness: soft, medium and hard.  And then of course there is durability, which is dependent on the type of material that the fin is made of. Last but not least: budget.

Measuring freedive fin efficiency

As we shell out hundreds and hundreds of dollars for fins we wonder whether this or that feature will really make a difference?  Or maybe we just hope that paying more will get us more efficiency in the water.   Fin performance is mostly subjective but I was pondering whether there is a way to empirically compare fin performance.  Back on our beloved Internet I found a study on SCUBA fins that compared over a dozen fins using multiple measurements.  It was way too involved for what I wanted to do but it gave me some ideas.  The author of that study mentioned an underwater speedometer that sparked my curiosity.  After another session on the Internet I had found an electronic and a mechanical underwater speedometer.  I was amazed these were available and a guy living across the state from me made the mechanical one.    The cost was reasonable and this gem would allow me do some empirical testing.  The electronic version was out of stock with no demand for manufacturing more.  It turned out the diver from Spokane had been testing SCUBA fins himself for over 20 years and his conclusion was that the bottom line on efficiency was max speed.

An underwater speedometer
An underwater speedometer

Others may suggest that kick cycles and other factors are important too, and they may be, but max speed would provide a standardized measure to compare fins.  I videoed the speedometer gauge with a Gopro to make sure I had recorded the speed correctly.  I could mention the various brands and flavors of fins I tested but the main characteristics are listed instead.


Fin type Blade/stiffness Blade material cost (US$) Speed (MPH)
Scuba/military Short blade Rubber 50 2.7
Freedive bi-fin Two brands Plastic 100 2.9 – 3.0
Freedive bi-fin Medium Fiberglass 300 3.3
Freedive bi-fin Soft Fiberglass 150 3.3
Freedive bi-fin Soft Fiber/Carbon 250 3.3
Freedive bi-fin Soft Carbon 500 3.3
Freedive bi-fin Medium Carbon 500 3.3
Freedive monofin model A Medium Fiberglass 200 3.4
Freedive monofin Model A Soft Fiberglass 200 3.4

The main points of the results are that going from Plastic to composite gets you a 10% increase in efficiency.  I can tell you from experience you might need that efficiency some day if you need to swim against our testy currents to get back to the boat.  But surprisingly, whether the fin was fiberglass or carbon, soft or medium stiffness they all had the same efficiency.  The monofin was a little faster but not as much as I expected. However, I felt like I could have used more room than a pool affords to really work the monofin to potential.

freedive fin efficiency
Dave holding the speedometer

Based on these non-scientific but empirical results, I don’t need to spend the extra cash for carbon which is good for my budget and the robust fiberglass construction will handle about anything I or the sea could throw at it.  As far as blade stiffness goes, I can choose either since they had the same max speed but I liked the soft blades. Soft blades have a wider range of resistance.  Kicking normally at slow speeds was effortless compared to the medium bifins, which required more effort to get the fins moving. Of course this is important, since we need to conserve oxygen.

This was a fun experiment and I hope it helps you while you contemplate your next freedive fin.  In our high-tech world we can get lost in the details. However most of the improvements in design may never be realized as we fin out to the next line dive or kelp bed.  But if we believe a particular fin will give us an edge, even if only a psychological effect, that could translate to better performance and possibly survival.  Just remember to peel off the soft #1 sticker.





Anus awareness, the key to long statics

This post was submitted by Luca Malaguti.

What on earth does the anus have to do with freediving? While training in Montréal with the Club d’Apnée Sportive de Montréal (CASM), I took a specialized static training and pranayama course. One of my teachers was a former student of Jacques Mayol. Jacques Mayol taught him an odd but effective visualization technique for static breath holds and pre-dive breathing up. As you can guess, this technique focuses on the anus.

Jacques Mayol advocated an attitude of calmness and relaxation through pranayama and various yoga techniques during competition, in stark contrast to a “forcing and packing”. Visualization techniques play a major role in his approach, and today these techniques are used and taught by some of the best freedivers and teachers such Sara Campbell, Umberto Pellizzari, and Federico Mana.

Mayol discovered that by visualizing different parts of the body he achieved a state of calm. He focused gently on the limbs in order to relax them and ‘shut them off’. This way he achieved a serene state of calm. This visualization teaches self-awareness and control, and is important for the sensations associated with diaphragmatic breathing. He took it one step further and, as part of his routine, focused on visualizing and relaxing the anus. Why the anus? Perhaps because it is one of the core areas where stress manifests itself physically. The rectal area contains muscles that we keep tensioned and clenched almost all day long. It is one of the last muscles of the body to be voluntarily relaxed.

Visualization for statics

The exercise as it was taught to me is as follows. While breathing up, be self-aware of your body and visualize the different parts (fingers, arms, feet, legs and neck) relaxing, unwinding and loosening them. You can focus on the individual limbs and muscles one by one. Take your time, this is not something you can rush. Once you achieve this you can indeed almost imagine yourself as just a torso and a head, floating in the pool. Lastly, and most importantly, is to imagine and see all the muscles around your entire pelvic and rectal area just shutting down. Just loosen all those muscles that are constantly tense while walking, sitting and yes, also when defecating. Our teacher told us, and maybe Mayol told him, “If you can relax the anus, then you can relax all the other muscles too”. The power of visualization is that we can be aware of all of our body and shut down the unnecessary components. Complete relaxation is the key to a long static. This exercise has served as a fantastic relaxation tool prior to a long static or for calming the breath before diving deep. I use this visualization technique often, and it serves me well.

The anus is an area of constant tension. If you are able to truly relax it, the benefits will resonate all over your body. Freedivers must be in harmony with every part of their body, and the anus, is a part of that.

And make sure to go to the toilet before your diving session.


More info on pranayama and yoga for freediving:

Yoga for Freediving by Sara Campbell


Freediving training during the winter

Daylight savings in British Columbia starts in early November. The days are now too short to get out in the ocean in the late afternoon. The angle of incidence of the light ensures that most light is reflected off the water surface, rather than penetrating to the depths. The water temperature has steadily dropped over the past few months. As if those two things are not bad enough, the weather does not usually cooperate with diving plans either.

Winter is a wonderful season to repair gear, but you also want to stay in condition. Pool training is a great way to do this. If you have a thick wetsuit, you can still do an ocean dive if the weather cooperates. You will unfortunately be limited to midday because there is so little light in winter.

Cross training for freediving

If you don’t manage to do any wet training you can stay in condition during the winter time with cross training exercises. For me personally, static performance does not appear to decrease much even if I don’t practice it. My CO2 tolerance drops dramatically however, and this is also the limiting factor on my ocean dives. One of my favourite cross training exercises is about 30 minutes on the upright bike. The first 10 minutes I crank up my heart rate to about 100. After that I do a series of breathholds while cycling slowly keeping my power output steady. It’s great for CO2 training. Make sure to do a cooldown exercise for your legs afterwards. (They will accumulate a lot of lactic acid and hence get sore and tired edit 11/11: the idea that lactic acid is responsible for muscle soreness is a persistent myth, see the links submitted by Cesar L. in the comments below). If you have an oximeter or if the bike has a heart rate monitor, keep an eye on it and log your stats. I don’t suggest you do this on an actual bike outside, biking in traffic and holding your breath is not a good idea for obvious reasons.

Freediving training in winter
A spinning bike in the gym. Another good machine to use is the upright bike, which has a backrest

Adjust your diving style

Diving in winter time is different from summertime dives. The sun will not warm you up during your breatheups anymore, so that you will get cold even at the surface. If you want to do 3 min breatheups in total stillness you won’t be diving for very long, even in a 6 mm+ suit. With a more active style of diving your muscles will generate more heat but you won’t dive as long or deep.

Freediving training in winter
No wetsuit required here

I sure do miss the tropics sometimes. What do you do to keep in shape in winter?






Repairing a fiberglass monofin: lessons learned

This post was submitted by Luca Malaguti, a freediver based in Vancouver, Canada.

A few months ago I was diving with my fiberglass monofin, looking for crabs near the shore. My fin got stuck between two rocks in a narrow passage.  To my dismay, a little bit of torque was enough to create a 10cm fracture in my monofin (see the picture below). Not only was my monofin fractured, but the location of the crack was so  unfortunate that with each undulation of the fin the fracture would inevitably propagate further.

repairing fiberglass monofin
See here the crack in my fiberglass monofin. The area around it is already sanded

My fiberglass monofin:

Here’s a little history about my monofin. I purchased it from, and had it (expensively) shipped to Vancouver, BC after having to pay even more in import fees. I bought the ‘Sport’ fin from the brand Leaderfins. Once it arrived, I noticed that both foot pockets were labeled “left”. On top of that the monofin was not symmetrical: one half was longer than the other by a few centimeters. As a starting fin it does the job, but beware of purchasing the cheapest products on the market. This fin was obviously improperly manufactured (the fracture itself was unrelated to its manufacturing).

Equipment for the repair job:

Fibertek, a fiberglass dealer in Vancouver, BC ( specializes in all fiberglass types and glues. I bought the toughest, and most heavily woven type of fiberglass (their medium weight cloth yard), and a special type of epoxy glue (the 250 mL epoxy resin for wet & cold curing and 125mL epoxy hardener both from Fiber Craft Aqua-Set). I used them according to the instructions (a 2:1 ratio) while keeping in mind temperature and humidity effects on setting time. In order to  repair a monofin, you will also need a stirring cup, a measuring cup, stirring sticks and a variety of sand paper (I suggest 80, 200 and 400 grit). You should also have nylon gloves and a mask, a wooden table board and a sharp knife (or better yet an X-Acto knife or even a scalpel to cut the fiberglass).

fiberglass monofin
Supplies for the repair job

The fix:

I sanded the spot around the fracture using the 80 grit sand paper around the crack. I then cut the fiberglass cloth with scissors but quickly learned this is a bad idea! Use a sharp knife instead on a flat wood surface to get nice clean edges, otherwise you’ll destroy the woven sheets and make a mess everywhere!

After cutting the fiberglass into strips (starting at 3cm x 5cm), I laid them perpendicular to the fracture and saturated them with the mixed epoxy. They have to be soaked but beware of putting on too much epoxy!

Subsequently I layered the fiberglass on top of each other over the damaged zone and allowed the epoxy to cure (2 – 3 days in a dry area).  Once everything is dry, you can use the 200 and then 400 grit sandpaper to smoothen the fiberglass. If you wish to paint it, make sure you use a paint specifically for epoxy and intended for marine activities.

Hard Lesson Learned:

Here’s the important part and what I learnt from my mistakes.

Patience is a virtue when repairing monofins. I should have been much more patient with fixing it: setting only a few layers at a time, allowing them to dry, testing the rigidity and then continuing with one layer at the time. The rigidity of a monofin can make or break your dive.

Secondly, pressure! I never thought of the epoxy as a chemical reaction but or course it is, and so if the layers aren’t tightly packed there will be some gas/air bubbles forming in between them. This will cause the fiberglass to crack or separate once force is applied. You really shouldn’t underestimate the amount of force generated while kicking underwater! I found this video, obviously after I made the mistakes, ( showing a method in drying the fiberglass epoxy using a “non-stick” polyethylene plastic, foam pads and weights.

To sum up the last two paragraphs: you should add layer by layer patiently. Allow them to dry, in the right environment, each time under heavy pressure. Failing to do so will result in improper settling of the fiberglass layers.

On the right hand side of the fin, the fiberglass/epoxy adhered properly to the fin’s natural fiberglass (picture below). On the other side it, the force of undulating the monofin was strong enough to rip the edge’s off, and then with water intrusion it just detached all the layers. Properly sanding down the surface before can go a long way; it will help the epoxy adhere to the smooth surface (which I forgot to do on the left side).

To be continued…



Taking care of your freediving wetsuit

The first wetsuit I ever used for freediving was a surfing wetsuit. The finest cheapest I could find. It came from Decathlon in France, and had a 5.5/4.5 mm longjohn and a 5.5/4.5 mm jacket. Combined I had 11 mm of neoprene on the core, and 4.5 mm of neoprene on my limbs. That wetsuit lasted forever. It was also about as flexible as a wooden board, and very heavy.

Diving in Vancouver in Winter, the water was probably 8 degrees C or less. This is me in my surf wetsuit, with scuba fins. Photo by Todd Kabaluk
Diving in Vancouver in Winter, the water was probably 8 degrees C or less. This is me in my surf wetsuit, with scuba fins. Photo by Todd Kabaluk

My next wetsuit was an actual freediving wetsuit, a 3mm speardiver from the freedive store. I still have it, although the original 3 mm neoprene now is about 1.5 – 2 mm thick. The wet suit has an unlined inside, commonly referred to as ‘open cell’, meaning that there is no lining on the rubber. Rubber against skin. That whole story of having a thin layer of water to help you stay warm? Total nonsense. If you have less water and/or water flow in your suit you are going to stay much warmer. Compared to my surf suit, diving felt like a trip to heaven and back. I then got a suit from Oceanos in Greece. Not the best suit I ever bought. It was a cheap custom suit, but the fit was not perfect. After a year of diving, the original 5 mm has compressed to about 3 mm.

I now dive with a suit from Azure Passion (review here). It is 8 mm thick, and so far (after 6 months of diving) it is still 8 mm. I take a lot more care with this suit, because it feels like a second skin, and, I really should stop buying a new suit every 8-12 months.

freediving wetsuit
Getting ready to dip into 12 degrees C water with an unlined wetsuit. Photo by Rick Waines

Simple tricks to make your freediving wetsuit last

  • Make sure the neoprene does not compress

Store your suit on a shelf without folds (My pants are folded once, and of my top the sleeves are folded at the shoulders). Do not put anything on your suit. I repeat. Do not put anything on your suit. Not your divelight, not your mask, and not your diving weights. Especially not your diving weights. If neoprene compresses it will lose its insulation. Not a big deal if you dive with a 1.5 mm in the tropics, big deal if you dive in BC in water that can be below 5 °C.

I stuffed my first suits into the smallest bag I could stuff them into. It was handy, especially when I lived in my van for 8 months. But it definitely was not good for the neoprene. Now I use a huge bag for my suits so that they have plenty of space. The quality of the neoprene is another factor. Yamomoto and Heiwa neoprene are currently the best available to my knowledge.

  • Make sure the neoprene does not stretch

You can keep a wetsuit on a hanger but some neoprenes tend to stretch if you do this.. This doesn’t happen instantly but it sure does happen. If it does you have created space for water to slosh around and this will keep you cold. This is part of the reason I keep mine lying on a shelf.

  • Take care of the small nicks and cuts as soon as you can

If you have an unlined wetsuit, don’t breathe at it! Chances are you’ll create a hole. These suits are fragile. Even a fingernail can create a small cut. That small cut will turn into a tear very soon. Keep neoprene cement in your diving bag (put 2 ziplocks around it in case it leaks) so that you can mend your suit on the go. Make sure you can put your suit on and off without having your fingertips against the rubber.