referred from Nathan Vinski postings in FB
Whether you are a beginner freediver who’s starting training after your first course, or a competitive athlete looking to get back into training after a few weeks off, what’s the first thing that you are going to do? Most likely it is going to be CO2 tables, but why?
From the moment you take your first course we are bombarded with the idea that the safest way to prolong our breath-hold is by increasing our CO2 tolerance, not hyperventilating (of course, I agree). When we move to the intermediate levels were taught that CO2 tables are the most effective way to train our breath holding capacity: By increasing our physical and mental tolerance to CO2. Finally outside of the course level, when you sign up to your first organized group trainings, what is the usual focus? CO2. Why.. because it is the foundation on which you can push your longer holds.
Of course I agree that a tolerance to CO2 and a tolerance to contractions, both mentally and physically, is going to be very important in your training.
That being said, unfortunately the the entire approach to CO2 training, and the way that it is being taught, are completely upside-down and ass-backwards.
Of course that might upset a lot of divers. They’ve been doing it for years, and their AIDA 3* course said it was so, but broken down into its components, it quickly becomes evident that the current models for CO2 training are basically useless, and I urge you to continue reading and do your own research on the topic, to avoid falling into the CO2 trap of doom and contractions.
First lets discuss the mental side of CO2 tolerance.
The goal in this area is to become more comfortable with the discomfort and contractions that comes with a breath-hold. CO2 training is currently approached by exposing your self to great-discomfot, in hopes that you one day become used to it. The reason this is a problem is because a person’s ability to withstand contractions doesn’t come from being used to them, its comes from their motivation to withstand them.
Guaranteed, any newly-trained freediver, with 100 million dollars on the line, or a gun pointed to their head, could perform a maximum static until blackout. This isn’t because they’ve learned CO2 tolerance, its because they have motivation. Plateaus in apnea performance are most commonly caused by lack of motivation to push through discomfort. Training yourself by having more discomfort can only serve to decrease your motivation too push through it.
Another negative effect of this type of training is that your subconscious barrier for contractions can become reinforced. If you do frequent classic-style CO2 training, even on a hold with low CO2 and a long preparation, your contractions will start where they usually do.. Subconsciously matching the time they come during your CO2 training.
A much more effective training for ‘mental tolerance’ to contractions would actually come from using a relaxation-based approach. Learning to tolerate contractions can be as simple as doing 2-3 breath-holds with 4:00 recoveries, and doing 1:00 of contractions without measuring the total time. A few sessions like this and the contraction time can be moved up to 1:15. This is all mental, so you only need to prove (once or twice) to yourself that you can do it. There’s no need to do 8 x maximum with 1 breath recoveries, just the need to prove to your mind that you can tolerate x-time of contractions. Once thats done its like riding a bike, you will never forget. Once you know you can tolerate contractions for 1,2 or even 3 minutes, then its going to be all about when they start, which is where physical tolerance comes into play.
So on to the physical side of CO2 tolerance.
The goal with this part of CO2 tolerance is to decrease the sensitivity that your body has to CO2. At least thats what we are taught. Although this desensitization can occur, it is only a very small part of what physical CO2 tolerance is. To understand it, we have to work backwards and get a grasp on what really causes the urge to breath.
To understand the bigger picture we need to stop thinking that the urge to breath is caused by CO2. What actually regulates our breathing are the PH levels of the body: more acidic = more need to breath. The reason this is important to understand is because the main deciding factor for for PH is the percentage of CO2 and lactate in the body, not the amount of CO2. So yes CO2 plays a role, but not exactly in the way we apply it to freediving.
To illustrate, lets take a theoretical diver who can hold a maximum of 1kg of CO2 in their entire body and has 0Kg at rest. They reach the uncomfortable PH level at 50% of total CO2 (0.5kg), and produce 0.25kg CO2/ 1:00 static. Their max will be 4:00 (based on discomfort) and their contractions will start at 2:00.
To progress they don’t actually need to decrease their sensitivity to CO2, they need to increase the amount of CO2 that their body can hold. There is a chemical in the blood, called blood-bicarbonate, that dictates how much CO2 we can hold, and if the diver was to produce more blood bi-carbonate they would increase their performance.
So, the same diver who can now hold 1.5kg CO2 (starting at 0kg) and produces 0.25kg/1:00 static could now do a 6:00 apnea. On top of that, they still get their contractions at 50% maximum CO2, which is now 0.75kg, and their urge to breath has moved up from 2:00 to 3:00.
So whats the ultimate goal of a freediver then? It’s not to increase tolerance to CO2, but to increase the amount they can hold, by increasing their blood bicarbonate. To train this this, we need to first understand the role of bicarbonate.
Blood bicarbonate is formulated as HCO3(-) or 1 hydrogen molecule with 3 carbon molecules. Basically, its CO2, with some extra hydrogen and carbon…
This next part is where the common-freediving knowledge of blood bicarbonate is incorrect. Blood bicarbonate is not a buffer for CO2. It is actually a CO2-based buffer for lactic acid. The more we have the longer it takes our body to acidify.
In short, more bicarbonate means later contractions, but understanding that its use in the body is to buffer lactic acid means that we much change the way we approach training this system. High levels of CO2 will not force our body to produce a buffer for lactic acid, we need lactic acid to do this.
Basically, all of that (based on research papers), goes to say that classic-style CO2 training will not be very effective in increasing your physical tolerance to CO2. In fact, breath holding (especially static where we produce no lactic acid) is pretty much useless for building physical tolerance to CO2. What we need to do is expose ourselves to lots of lactic acid in order to produce its buffer: Blood bicarbonate, which has a bonus effect of improving our CO2 tolerance, though this isn’t its intention.
The best type of training that we can do is some sort of high intensity interval training (HIIT), or short high-heart-rate endurance training, like reps of 400-800m runs for example. The goal is to maintain moderate-high levels of lactate in the blood for extended periods of time to increase our lactic buffers (bicarbonate), which in turn decrease the rate at which we become overly acidic, causing our contractions to come later in the breath-hold. **Remember breathing doesn’t regulate CO2, it regulates PH levels by adjusting CO2.
To summarise, conventional CO2 training is most likely wasting your time. Much, much more can be achieved by understanding the 2 separate sides of CO2 tolerance and training them more efficiently than with normal CO2 tables, or even the currently more popular 1-breath tables.
The mental side of CO2 tolerance is simply the confidence that you have in your ability to withstand contractions for a certain amount of time. This confidence isn’t going to be build by beating yourself down over and over again with 1-breath tables, its built by doing a set-time of contractions 1 or 2 times. Once you know you can do 2:00 of contractions (for example), that ability stays with you for life, as all it comes down to is the confidence and motivation that you can do it again.
Physically, there is a way to push our contractions later into the breath-hold by increasing the amount of bicarbonate that we can hold in the blood. Just remember, at a basic level, blood bicarbonate is not a buffer to CO2, it is the CO2, and its job is to act as a buffer to lactic acid. To train our lactic buffering system we need to expose ourselves to high levels of lactate (not high levels of CO2) by doing high-intensity interval training or anything else that taxes the anaerobic systems for extended periods of time. The effect is that this increased ability to buffer lactate has by consequence is an increased ‘time-to-contractions’ during a breath-hold.
Train smart, and the results will come.
On the other hand, physical CO2 tolerance, or making your contractions come later is, in part, related to the amount of blood-bicarbonate that you have in your body. This chemical, HCO3(-) acts as a buffer to carbonic-acid (H2CO3, or CO2 dissolved in the blood plasma). HIIT training is a very efficient way of increasing you bicarbonate levels, and in short, the more we have the longer it takes for the CO2 we produce during a breath-hold to become uncomfortable.
These types of training are things that need to be done semi-regularly and in advance, but what can you do on the day of a competition or PB attempt, to give you that little extra edge with CO2 tolerance?
Again, understanding this comes from the knowledge of how CO2 is stored in the body. CO2 can be stored in 3 main places (of course there are some other minor places but these play a much smaller role). These places are the lungs (CO2), the blood plasma (H2CO3 (carbonic acid)), and the body water (H2CO3 (carbonic acid)), which is actually our biggest ‘container’ for CO2.
Again, we have to remember that the urge to breath (contractions) is not caused by CO2 itself, it is caused by an acidic shift in PH from a rising % of total CO2.
So what is a solution to slow down this % buildup of CO2? Increase the size of the container so that each unit of produced CO2 is a smaller % of the total. For the lungs this is simple, stretching and packing can help, but considering that the lungs play a very small role in CO2 storage, there is a more effective way (although stretching is still important for O2 storage and relaxation).
What we should try to do is increase the amount of space for CO2 (H2CO3) in the blood and body water. The reason for this is simple, broken down H2CO3=CO2+H20, carbon dioxide and water. The more water we have in our body, the more CO2 we can hold.
For the blood plasma this is simple, drink lots-more water before your dives, and your blood will be able to hold more CO2. Again, the blood isn’t our largest CO2 storage unit, whats even more significant is the water held in our muscle tissues. A very effective way of hydrating the muscle tissues is eating, and loading the body with carbohydrates.
The reason for this comes down to glycogen. This is the sugar that our body produces (from all those carbs), and is stored in the lean-muscle tissues and liver. The reason this is important is because 1 gram of glycogen can hold onto 3-4 grams of water, all of which is in the muscles, ready to absorb any CO2 you are producing on your dives. This can play a particularly significant role in any non-static diving because we are now able to absorb the CO2 from its source: The muscles we are using to fin.
Loading carbohydrates will increase glycogen, and therefore water in the muscles which can give you an edge with CO2 tolerance. The way to do it effectively has the potential to get very long winded.. but I will keep it short and simple.
The most effective way to absorb carbohydrate and store glycogen is to take your carbs with multiple forms of transporters. In short, you should eat: Glucose, Fructose, and Salts (salts also help with hydration). Some studies have shown that taking your carbs with caffeine can also increase your ability to quickly store glycogen (so all you coffee lovers, you can still have your morning coffee even before a big dive).
heres one on caffein and glycogen: https://www.ncbi.nlm.nih.gov/pubmed/29345166
Of course this needs to be done a few hours before diving so your body isn’t still digesting, and the stimulant effects of the caffein have mostly worn off.
As a bonus, glycogen is the fuel we need to sustain our muscle-function during a big dive, so storing more is a win-win situation.
The main thing I would like to say in regard to this post, and the previous bi-carbonate post, is that physical CO2 tolerance plays only a very small role in when your contractions come. If they are starting very-early it is most likely due to a technical or mental issue and a few workouts + come hydration is not a quick-fix to all of your problems.
In either case, I always think its nice to have an edge in any-aspect that you can control. Eating some nice food and drinking water isn’t hard to do, and even if this accounts for only 3% (I made up that number, don’t quote me on it), its still a free 3%, no matter what level of diver you are.
Personally, I have had very good results (noticeably less muscle fatigue and some reduction in urge to breath) in depth diving when I eat a big fruit salad and drink 1l of water with hydration salts. This is easy enough to digest that I can dive an hour later.