Before we start to compare neck weight with the weight belt, let’s make sure everybody understands why we need additional weights.
When a Freediver swims underwater in the swimming pool, he needs to be at 1-2 meters deep and not sink or float up. However, as most people are positively buoyant (float up) at such depth, they need to put some extra weights on to be neutrally buoyant (stay on the same depth without floating up or sinking). This is even more important if you use a wetsuit.
Buoyancy is a unique feature, and two freedivers with similar weights and height may have different buoyancy and need different weights.
If the weights influence the buoyancy in general, then the location of weights impacts the streamline position. And an excellent streamlined position helps a lot in conserving oxygen.
If all your weights stay around hips, then, after a freediver makes a deep inhale and starts swimmin underwater, the chest area will be more buoyant (float up), and legs will be less buoyant (sink).
I am not saying that the weight belt is not practical in freediving – you can see that many freedivers, especially beginners, prefer to use it instead of the neck weight.
First of all, it is more convenient to wear weights on the hips than on a neck, especially if it’s 3-4 kilos heavy. It takes a while to get used to a neck weight and be comfortable with it.
The second reason – is that weight belts are more prevalent in freediving centers because they are more multi-functional and durable, so high chances that you get it if you rent equipment from the Freediving center.
And the third reason – it was not so long time ago freediving brands started to manufacture neck weights. Before, if you want to have a neck weight – you have to make it by yourself.
But what are the advantages of neck weight?
The first one – you can adjust its weight more precisely.
Weights for the weight belt have a fixed amount of grams – 500, 800, 1000, etc. For example, in our school, we use 800 and 1200 grams. In contrast, you can make your neck weight match your buoyancy much more precisely.
The second advantage – location of the neck weight improves body position and provides more streamlined (horizontal).
Nowadays, you have a choice – you can either buy a branded neck weight or make it by yourself as in good old times. All you need for the handmade option is a bicycle tire, some filling, pair of clips, and insulation tape.
This is the cheapest solution, and you can use it both for a pool and the ocean.
But if the water temperature in your pool varies and sometimes you need to wear the wetsuit and sometimes you don’t, you need to adjust the amount of the weights. This isn’t easy to do with a handmade neck weight. What you can do in this case is make several neck weights, which would fit every wetsuit you have.
Or you can buy the adjustable neck weight.
Lobster, at the moment, is probably the most popular brand in the freediving market. This is because they created a very comfortable and good-looking weight system, which spreads the weight around the neck and along the spine. The only minus of Lobster neck weight is that it is not convenient for depth diving, despite the manufacturer still recommending it.
By Svitlana Gaidai
If you are looking for the best neck weight for the pool freediving check out Lobster company. Use promo code KAIZEN and get 10 % discount for all their products.
Static Apnea (STA) is usually the first thing any Freediver learns, whether on a freediving course (learn about Freediving course) or while lying in a bed.
STA is the easiest way to learn all the steps – relaxation breathing, relaxation during breath-hold, recovery breathing. You even don’t need that much equipment – mask if you do it in the water, or nothing if do it “dry.”
It sounds like a perfect combination, right?
STA also helps gain confidence before moving to more advanced Freediving disciplines such as Dynamic Apnea (DYN) or even depth disciplines.
However, if your main goal is to dive into the Ocean, there is a better option.
But first, a little bit of theory. When you dive into the Ocean, there is no such feeling as extreme fullness in the lungs (which you have when you do a full inhale before normal STA). During the descent, your lungs get compressed quite quickly due to the increase of ambient pressure. As a result, the volume of any gas (including air in your lungs) will decrease accordingly.
How can we simulate it on land?
The answer is empty lungs STA training. Start with relaxation breathing as usual, but before breath-hold, instead of full inhale, you do full exhale. After that, do the same as with full lungs breath-hold – be as much relaxed as possible.
Since your goal is not absolute time but rather relaxation (get comfortable with the feeling of “smaller” lungs) – you don’t need to push yourself (at least no need to do it often).
Just be relaxed before contractions start and during the first few.
I like to do empty lungs STA in the form of an O2 table.
If you have never done such training before, here is an example (this is how we do it for the first time with our Advanced Freediver students)
And keep in mind, if you are planning to do this training in the water, ALWAYS train with another Freediver, who knows how to do safety (video how to do Safety) and knows Rescue procedure (video how to do Rescue).
Looking for the best Freediving computer? Check out this link for Suunto D4
In one of the last post, we discussed how you can train static (in case if you missed it, read here). And what about dynamic?
If for static you can do dry static apnea, then for dynamic you obviously need a pool.
Normally you can learn DYN on any PADI Freediving courses, but if you haven’t done any dynamic on your course, might be this video can help.
When you do static apnea – it is complete relaxation. The same principle can be applied for DYN – relaxation is the key. But in dynamic obviously you couldn’t relax all your muscles (since you need to move forward), but you should relax all the muscles not involved in this movement (neck, shoulders, etc). And even muscles which involved in the movement should be relaxed at the moment when you finish the kick (gliding phase).
Hopefully, it doesn’t sound too complicated.
How often do you need to train DYN? I think 2-3 times per week is enough for beginner Freediver. How intense? Not intense at all! Progress will come naturally.
There are few things about your technique, you want to be focused on. Choose one of them for a session and work only on it (let’s say be focused on your shoulders relaxation
the whole session).
How do you know your mistakes? Ask your buddy to film you (GoPro does the excellent job)!
Head position (should be neutral)
Relaxation in the shoulder area (quite often too tense)
Buoyancy (the first thing which you have to fix!)
Kicking both directions
Start kicking from your hips
Not bending knees too much
And here a couple of examples of DYN training
Main training – do short laps with 100% concentration on technique (mentioned above) and relaxation. If you current MAX less than 50-70 meters, do ONLY this training. Approximate distance 40-50% from your MAX. Amount of repetitions 5-10
Easy classic CO2 training. Let’s say 25 meters with 30-60 seconds rest. 10 repetitions. A bit harder than the previous exercise.
Over-under. Swim short distance (less than 40-50% MAX) underwater and without rest, swim same distance on the surface. Repeat 5-10 times. Can make it a bit harder if decrease surface distance.
PADI Advanced Freediver
Sorry to repeat one more time – focus on the technique and relaxation.
Do it for a month and then can try to increase your PB by 5-10 meters.
All the training should be done ONLY with another Freediver!!
If you are looking for the best neck weight for the pool freediving, check out Lobster company!
Use promo code KAIZEN and get 10% discount for all their products!
When you start freediving it seems, that only equipment you need is a pair of fins and mask with a snorkel.
But after a while, you discover that there is so much stuff can be additionally used. You can easily live without it, but freediving training is going to be much more effective and fun with it
Today we are going to talk about one of these freediver’s toys – a nose clip.
As soon as you get the nose clip, probably static breath hold in a pool with it will be your first choice. At least this is what we are doing on a PADI Advanced Freediver course
What is the difference between using a mask and a nose clip – with the nose clip you have your whole face contacting with the water, which will help to trigger mammalian diving reflex (MDR). And it is strongly important for freediving as MDR influences blood shift, decrease heart rate and force your spleen to contract.
Some freedivers prefer to combine nose clip with another useful toy – swimming goggles. It is a kind of compromise between a mask and a “naked” face. It depends on your personal preference to wear goggles for static apnea or not. But keep in mind how sensitive your eyes are to pool water and chemicals in it. If you feel comfortable to stay in water without goggles – you are more than welcomed to do it. Just try and you will see the difference.
Another case where you can use your new nose clip in a pool is dynamic apnea. You will see how completely different your feeling going to be. And you will realize it, not when you replace mask with nose clip and goggles, but let’s say when you wear the mask again. This is quite similar to feel the difference in diving in a wetsuit and in a swimsuit.
And the last step for you in getting closer with a nose clip will be diving in the open water, where hands-free equalization provides you with a lot of opportunities to evolve as a freediver. Free Immersion and No fins are probably two main disciplines were you can improve technique efficiency without a need to pinch your nose every meter.
Monofin and bi fins dive also will become more streamlined and hydrodynamic if you don’t need to bring your hand to the nose for equalization. It will allow you to glide in water more smooth and effortless.
The same as in a pool, in open water it is completely up to you to use goggles or not. Of course, for depth trainings, you cannot use swimming goggles, which you use in a pool. In this concern, we are coming to another not compulsory but such a lovely accessory for freediving as goggles for deep diving. Nowadays such goggles can be two types – membrane lenses goggles (equalize automatically) and fluid lenses goggles (do not require equalization). But as I have mentioned above – there is no strong need in this. And probably one of the best proof that nose clip only diving works effective – it is extremely popular among high-level athletes at the competition.
Freediving, as a recreational water-based activity (as well as a sport), getting more and more popular. But still, it is far away from other water activities, like for example scuba diving.
There are a lot of myths around Freediving, which stopping people to try it. Or at least confusing.
Let’s try to find out which one is true and which one is not. So, let’s start!
Freedivers can come much closer to the marine life. NOT TRUE. Well, actually it depends. If you compare an experienced Freediver and a beginner level Scuba Diver, then it is true 100%. But if we compare both an experience Scuba Diver and a Freediver, then it is not that simple. As a former scuba instructor, I had a few thousands of dives and I can say that majority of the marine life can come very close to you (reef fish, turtles, stingrays, sharks etc). Less than a half meter. Some people are saying that fish afraid of the bubbles. But why should they be? Fish are afraid of their natural predators and they don’t make bubbles. Fish afraid if you make too much movement and if you are rapidly closing the distance. However, I am willing to accept that some marine life can come close to a Freediver (at least I was told so by other Freedivers).
Freediving is more environments friendly. TRUE. Freediving boat is usually much smaller and requires a smaller engine. And they don’t have compressors. It reduces air and water pollution (as well as noise pollution). All of this makes a difference on our impact on Nature. Also, Freedivers are usually not that close to the corals (especially beginner level), so, fewer chances to damage fragile corals. We are also diving on the reefs less often (mainly we are diving just in the blue).
Freedivers have less equipment. ALMOST TRUE. If you compare Freediving vs Scuba Diving – you will probably think – oh, this is 100% true, but it is not that simple again. If we are talking about starting – then for sure it is true! As soon as you have a mask, you can be a Freediver 😉 For scuba, even for absolute beginner level, there is a standard set – BCD, regulator, fins, scuba tank etc. Coming back to Freediving, like I said, in the beginning, you can just invest in the mask and snorkel. But then it will probably be more equipment – weight belt, neck weight, wetsuit, nose clip, safety lanyard, goggles for the swimming pool, float and rope if you want to train with your buddy independently, etc.
Freedivers are leading a healthier lifestyle. TRUE. Some people like to call Scuba Diving sport, which always confuses me. Obviously, it is not. But freediving is. Even if you are not very serious about results. Freediving training combines correct breathing, different relaxation techniques, different physical exercises (in open water, pool, gym etc), as well as mental training. So, yes, if you like to be connected with Nature and stay healthy – Freediving should be your choice.
Freediving is more dangerous. ABSOLUTELY NOT TRUE. Let’s make a line between Freedivers who are properly educated and follow safety rules and someone who has no idea about basic safety rules and just decided that he/she needs to dive deeper or hold the breath longer. Among the first groups, some problems occur, but they are not fatal. The second group is just playing Russian roulette. But the same is true for any other activity in our life – you have to follow safety rules. Even for walking. Disagree? Try to walk across a high way! When someone tells that Freedivers are dying regularly, I am always asking where this information is coming from. And there is no answer. Simple because it is not true. So, the bottom line here – follow safety rules and Freediving would be the safest water based activity!
Freediving is a more natural way to be underwater. Well, of course, it is TRUE. We don’t create with the scuba tanks on our back. But we have reflexes which help us to stay underwater longer and dive deeper. Holding the breath for a certain time is natural for us, as well to the other marine mammals.
So, what would be your choice? Ideally, try both freediving and scuba diving! In my opinion, if you want to explore reef up to 15 meters deep – Freediving is a much better choice. But if you are planning to explore a dive site 25-30 meter deep, then it is easy to do with a scuba tank. If you are interested in underwater photography or videography, then again, having scuba tanks make your life easier. On the other hand, if you want to enjoy to be underwater and also combine it with a healthy lifestyle – Freediving is a better choice.
If you are interested in proper Freediving education click HERE 😉
What is the best way to learn how to hold your breath? Of course, it is signing up for Freediving course 😉 But if you couldn’t do it at this moment (or did it and forgot), here is a small review about it!
If you haven’t read my previous post about breathing in general – check it out here
So, any breath hold has 3 parts – preparation, breath hold itself and proper recovery after it.
So, the first part is relaxation breathing.
We can say there are two main types of relaxation breathing
First one, let’s call it “old school” relaxation breathing is when you are trying to slow down breathing rate by extending your inhale and especially exhale part. There is even recommendation – exhale twice longer than inhale (not sure why twice). Let’s be honest – it is a mild version of hyperventilation (if you extend your exhale over a period of time, you removing extra CO2 from your body). I think Goran Ccolak said in his interview to Freediving Café, that every breathing, which differs from tidal breathing is hyperventilation. The question is how big ;-).
Yes, you are going to feel that you need to breathe less and less. But if you remember, your respiration rate regulated by the amount of CO2, reduction of CO2 will cause a reduction in the breathing rate. But do you want to reduce your CO2 level? Just quick reminder – if your CO2 level is low then O2 delivery going to be not that effective (Bohr effect).
You also creating some resistance for your respiratory muscles, right? And it potentially won’t allow you to completely relax (this is my opinion).
The second type of relaxation breathing is a relatively new way of warm up. Instead of extending the duration of your exhale, do tidal breathing and then just 1-2 big breath in (with passive exhale) before actual breath hold. Same breathing what you have before you fall asleep. Still better to use diaphragm breathing for it though (it means that you still want to learn and practice it). Let’s say for two minutes you are doing tidal breathing. You relax your muscles and mind. Your heart rate will go down since you are more and more relaxed. And your CO2 level not going to be high as well. But at the same time, it is not going to be below the normal level for this particular level of activity.
I remember first time read about it on William Trubridge FB page (hope I am not wrong here) and then Alexey Molchanov said the same on a Deep Week in Amed, about his breathing routine before a dive.
And lastly, another Freediving champ Adam Stern was talking about this type of Breathing on one of his last video!
Questions are – what to do while you are holding your breath and what happens in your body?
The answer is – try to become as much relaxing as possible. Easy to say, hard to do. What I recommend for my beginner students is to “scan” their body during breath hold and check if their muscles relax or not.
Face muscles (especially around eyes and jaw), neck, shoulders, arms, belly area, hips, ankles. And then do it again and again. Sooner or later you can relax without such “scanning”, but in the beginning, it is VERY useful!
If you are a beginner, not tolerance for a high level of CO2 or low level O2 important. It would be later. Now, you need to learn one of the most important parts of Freediving – how to relax!
So, you finished your relaxation breathing, made a big breath in and start holding. You managed your relaxation and completely relaxed. But all functions of the body are still working. So, you are still producing energy and as a byproduct, producing CO2. At some point, the CO2 level reaches a certain level and your respiratory center (RC) will send your muscles to remove this CO2 from your body. And you have the first contraction (movement of your respiratory muscles).
And what happens at this moment with your O2 level? It is going low for sure, but you still have plenty of O2. Enough for every body’s cells. And you know that and this is why you are keep holding.
Another contraction, a little bit stronger. But you are a Freediver and RC not dictated you what to do anymore. So, you are keeping holding. RC disagrees with you and sending you another command to breathe. Another contraction. And another. And they become a bit tougher.
Ok, you decide to finally follow this command and finish your breath hold! How? By start doing recovery breathing!
Ok, last part, recovery breathing. Why do it? During your breath hold (static, dynamic or depth) you use some O2. Longer you hold your breath, more O2 you use. Less O2 you have, higher chance of LMC/BO/SWB.
But as you remember, you start feeling discomfort, not because of low O2, but because of high CO2. So, when you stop holding your breath, what is your main goal – reduce the level of CO2 or increase O2?
The second option is correct. During your recovery, you don’t care about the level of discomfort (level of CO2), you care about not to lose your conscious!
First, exhale doesn’t have to be full (passive exhale more than enough) followed by full quick inhale. And you repeat it 3-6 times (or longer if you need it). Some Freedivers also do a “hook” breath – it is when after full and quick inhale, you keep this air for a second before exhaling.
And don’t forget while you are doing recovery breathing it is much safer if you have a support – float, side of the pool or anything else.
Another important rule – do recovery breathe every single time, not only when it was “hard” dive. Even after very easy dive you need to do it – it will help you to create a very useful habit and put it on a subconscious level!
Thank you for reading! If you have Freediving friends, who might find this article helpful – feel free to share! And if you have any question about Freediving – please let me know in comments below!
Is it possible to have DCS for Freediver? Unfortunately yes…But at the same time, it is quite easy to put the risk at the minimum. At our school, we normally discuss in details this topic at PADI Master Freediver course, so here are our thoughts on this subject…
In scuba diving, when you are breathing compressed air underwater, your body is saturated more and more with Nitrogen (79% of the air is Nitrogen). The chain looks like this – you breathe in the compressed air from a scuba tank and now the pressure of N(Nitrogen) in your lungs more than in your blood, so, it going to your blood. And now in your blood pressure of N is higher than in your tissues, so, it is going to your tissues. Until you have an equal pressure of N everywhere (this is what we call saturation). And when you start coming up, opposite happens. Now pressure of N is smaller in your lungs, so the reverse process is happening – from your tissues N going to the blood and then to your lungs and then you exhale it. But it doesn’t happen that quickly. In some tissues, this process is slower than in others.
So, this is why when scuba divers coming up, they need to do it slowly (in this case N slowly coming from your body with every exhale) and they also need to have a long surface interval between dives (to release as much N from their body as possible before the next dive). And why they can spend the only a certain amount of time on certain depth (not to get too much N to their tissues).
If they violate these rules, they have a very good chance to have DCS! Without making it too complicated, DCS is when molecules of N combined in your blood (or tissues) in the form of a bubble and can cause very serious damage!
But why it can be an issue for Freediver?
Among the first, spearfishers who were shooting fish relatively deep (around 20 meters) noticed that after the long session they have symptoms which are commonly associated with “bends” (another word for DCS). So, imagine you dive to 20 meters. On the surface, you did big inhale and bring this air (and around 79% of it is nitrogen) to 20 meters, where the pressure is 3 times higher. So, the pressure of any gases inside your lungs (we call it partial pressure) going to be also 3 times higher. If the pressure is going to be higher in the lungs, then it will go to your blood and further to your tissues in the attempt to reach equilibrium. When you start your ascend, the reverse process will take place. But not 100% (some of our tissue need time to release N2). Some N2 will still be in your tissues. Very very small amount. Not a dangerous amount. But then you are going to do 50 dives more to this depth. And now you have much more N2 in your blood. And on your next ascent, it can forms bubbles and this is DCS….
There are also some predisposing factors which can increase the risk of DCS. Let’s name a few
High level of CO2
Not enough surface time
As you can see, spearfisher who is doing a long session with relatively deep dives and small recovery time has a very good chance to get DCS….What to do, if you are spearfisher? Limit duration of your spearfishing session, have enough rest between dives, use appropriate thermal protection, stay hydrated!
Ok, what about DCS for Deep Freedivers?
Let’s say you are one of the most famous Freediver of all time, Herbert Nitsh, and diving not to 20 meters but to 214 meters!! You make a big inhale as possible (don’t forget, around 79% of inhaling air is N2) and put it under a huuuuuge pressure of 21 atm (this is what you have at 200 meters). During your descent, this N2 from your lungs will come into your bloodstream and from there to your tissues.
And now you will start your ascent. It would be No Limit discipline and you are not going to use your muscles for going up (which is very good to reduce the risk of DCS), you are probably also not dehydrate it nor cold (which is also very good)
But you are quite fast for this huge amount of N2, dissolved into your tissues. The bubbles will form. But not big in the beginning. But when you ascent with the constant speed, they are going to increase in size (because the pressure is decreasing). How to prevent it? You need to slow down…And this is what Herbert did – he dramatically decreased his ascent rate after 50 meters (from 3 m/s to about 1 m/s). He also did some safety stop at 10 meters to make it even safer. And this is how he became The Deepest Man on Earth by making a dive to 214 meters!!
But later, when he was trying to beat his own record he lost his conscious on his way up and failed to do all of the above (safety stops and slow down his speed). As a result, massive DCS….Luckily (actually his story of recovery is almost like a miracle) he survived and recovered from it!
But if you are diving not that deep, let’s say to 40 meters; is it possible to have DCS? And the answer is yes… Last year Freediving legend William Trubridge got DCS during his routine training. I mean routine for him but crazy for all of us! Let’s have a look at it
William did 5 dives to 40 meters with “hangs”. Time of each dive was about 1.50, the surface time between dives only 2.15. As a result, after his 5th dive, William felt one of the symptoms of DCS – numbness in his leg. He went to a hospital and took special treatment for DCS there (pretty expensive!). This story has a lucky end as well, William completely recovered and competing again!
According to him, he done this type of training before (even harder) and never had any problem.
So, what is the problem here and how to avoid it? The dives were not too deep and not too long (especially if you are World Champion). But the recovery time was quite short.
So, if you are just starting freediving – this is a basic advice – DO have long surface intervals. How long? Here a couple of ways how to count it
The time between your dives should be 3-4 times longer than your dive time. For example, if your dive time 30 secs, then have a rest for at least 2 mins
Divide dive time by 5 and the result is a time in minutes. If you dive to 40 meters, have a rest for at least 8 mins.
And be even more conservative – have even longer rest!
A few things which I would you to remember
First of all – symptoms of DCS. Type 1 DCS – skin rash on shoulders and upper chest, joint and limb pain. Type 2 DCS – peripheral tingling and numbness, unconsciousness, respiratory arrest and paralysis, coughing, feeling of air-starving.
Second – predisposing factors. Obesity, intense exercise less than 12 hrs before diving, age, fitness level, dehydration, injury and illness, alcohol, carbon dioxide, cold. Obviously, scuba diving before freediving is absolutely no-no!
Treatment for DCS – the patient should lay down and breath 100% O2. Transportation to a recompression chamber should be organized as quickly as possible.
And one more times how to avoid DCS
Don’t freedive after scuba diving
Have enough surface interval
Don’t ascent very fast from the deep dive
Reduce the number of deep dives in one session
Limit the duration of the dive session
Stay hydrated and use an appropriate wetsuit
Don’t consume alcohol and don’t do intense exercise before a session
Stay safe, enjoy Freediving and educate yourself about the activity which you love!
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Let’s start with understanding why we (as humans) breathing. Yes, we all know that we need O2 (oxygen) for our life and this is one of the main functions of our respiratory system – bring O2 to our tissues.
But do you know that our breathing rate is mainly regulated by the amount of CO2 (partial pressure of CO2) in the blood, not O2. We even have a specific part of our brain responsible for this regulation. It has a very difficult name – Medulla Oblongata. This “thing” is responsible for such automatic functions as breathing, heart and blood vessels function, swallowing, digestion.
Why is it important to know, especially for beginner Freedivers?
Well, we all know that some of our tissues couldn’t operate without O2 even a short amount of time. For example – our brain. And when beginners hold their breath and feel the desire to breathe, they start to be nervous because they are thinking the level of O2 critically low! And it is becoming dangerous!
And – if not, why they feel uncomfortable?
Let’s say you are holding your breath for a minute.
Even if you are relaxed as much as possible, you still produce some energy. And as a result, produce some CO2. And when your CO2 reaches a certain level you want to breathe (actually you want to remove excess CO2 level). In Freediving quite often we use the term “urge to breathe”. So, how are going to bring new air to your lungs? What is the process looks like?
Our main respiratory muscle is our diaphragm. It is a big muscle between your chest (thoracic) cavity and abdominal cavity. When you need to inhale – your diaphragm going down (contraction of the diaphragm), chest volume increase and the air suck in. Reverse process happens when you exhale – you relax your diaphragm and it is coming to its normal position, pushing the air out of your lungs. Intercostal muscles (muscles between your ribs) involved as well, helping you make a bigger inhale or exhale.
And now let’s come back to urge to breath. When you are holding your breath and have an urge to breathe – it is simple contractions of your respiratory muscles (diaphragm for example), which are trying to remove CO2 from your body.
As a beginner, you want to stop holding your breath after you have a contraction, or a few seconds later (5-15 is a good start). But with the practice, you can hold your contractions much longer. And let me remind you, that contractions are not connected with the level of O2, it is a simple response of your respiratory system for a high level of CO2. So, you are safe when you have them, don’t be scared.
But what exactly happens with the air, when it comes to our lungs? You inhale fresh air (only 21% is O2, 78,96% N and 0.04 is CO2) and it starts its journey into your circulatory system! There is a natural dead space (no one dies, there is just no gas exchange) on its way (nose/mouth + trachea + bronchi + bronchial), so when air reach your alveoli, it has less O2 than you when you inhale.
Your alveoli are tiny compartments where gas exchange happens between your lungs and your blood (capillaries). The wall of alveoli is thin enough for gas (gas traveling both directions, from alveoli to blood vessels and back) and not thin enough for liquid (this is why blood normally couldn’t penetrate into your respiratory system).
So, from alveoli, O2 moves into your blood, where most of it binds with the hemoglobin and use it as a taxi to get to different tissues (your muscles for example) through arteries.
And within your tissues, cells use O2 for producing energy and also creating CO2 as a byproduct (as well as water). After CO2 produced, it goes to your blood (partially connected with hemoglobin, but mostly dissolved into the plasma – bicarbonate) and then going through veins to your lungs. Then again, through gas exchange, CO2 penetrates to your alveoli, going all the way up to your mouth and then you remove it through exhaling! This how we are breathing!
Pretty simple, right?
A few words about the importance of CO2 in our body.
If CO2 is just a byproduct of producing energy and our “urge to breath” depends on it, might be we need to remove it from our system before a breath hold activity? And then can stay underwater longer?
Probably same thought had freediving pioneers when they were doing hyperventilation (which is a big no-no nowadays). Basically, hyperventilation (or over breathing) is the process when you ventilate your lungs too fast.
What happens when you do hyperventilation – you reduce the level of CO2 in your body, which cause increasing pH of your blood (blood become more alkaline – respiratory alkalosis) and it triggers Bohr effect – now a connection between hemoglobin and O2 becomes stronger and exchange between capillaries and tissues becomes harder. In simple words – even if enough O2 present in the blood, it is much harder to deliver it to tissues. Since the human brain is very sensitive to the lack of O2, as a result of hyperventilation we have symptoms – dizziness, tingling in the lips, hands or feet, headache, weakness. Or in a worst case scenario – unconsciousness (our brain simple protect us from further depleting of O2).
So, CO2 playing an important part in keeping pH of our blood constant (7.34-7.45), so-called acid-base homeostasis
Thank you for reading! hope you found some useful information here 😉
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There are 4 types of certificates which you can get doing freediving courses with PADI:
Basic Freediver, which is advisable for students under 15 years old. In the meantime, the youngest age for this course is 12 years. Minimum static breath hold is 90 seconds, Dynamic apnea (horizontal) at least 25 meters. Only Confined water sessions are foreseen for this level with maximum depth 6meters.
Freediver, which could be unofficially called 1st level. The minimum age for students is 15, but till 18 years depth requirements are not so high. Or better to say – not so deep 🙂 So in frames of this course, we have minimum 1 confined session and 2 open water sessions. You will become a certified Freediver as soon as you: can hold your breath up to 90 seconds, can swim underwater in fins at least 25meters (horizontal) and reach minimum 10 meters depth in constant weight (simply saying diving in bifins). Maximum depth for Freediver is 16 meters constant weight. There are certain requirements for rescue skills at this level, which can easily be explained – as PADI Freediver you can train on your own with certified freediver buddy. Which means both of you should be aware of safety and how to provide some rescue in case of shallow water blackout or LMC.
Advanced Freediver, which could be considered as 2nd level, consists of at least 1 confined water session and 2 open water sessions. Minimum static breath hold should be 2 minutes and 30 seconds, dynamic apnea in fins at least 50 meters and constant weight dive – minimum 20 meters. Maximum depth for this level is 24m. It also should be mentioned that to apply for Advanced Freediver you must get EFR first. That is also simply explained with the possible necessity to provide first aid to your buddy. And of course more advanced rescue skills should be demonstrated at this course.
And finally almost professional – Master Freediver. Let’s say that is the last level “for fun”. Next step would be Instructor. So to become Master (of Freedivers Power). Minimum depth to follow the path of Freediver Jedi is 32 meters. In frames of this course, your static breath hold should be at least 3min 30sec and dynamic in fins at least 70 meters. Besides, you will start learning mouthfill, no fins diving and few other cool things as managing the rope and buoy. After completing this course you cannot teach freediving but you can assist to the instructor during the courses.
Hope it’s a bit more clear now with PADI requirements for each level of freediving course.
Soon I will prepare this article in the Russian language 🙂