How to improve your air consumption to stay longer underwater
Do you always have to finish your dive before your buddies? Did none of the advices you got to improve your air consumption worked out? You don´t want to learn meditating or Yoga to lower your air consumption rate? Read this and change your diving forever!
Be proud to show your pressure gauge
If you are a scuba diver and have ever been on a dive with a group you know this after-dive-talk: “How much air you have left? What? Only? I have that much!” Or “How are you doing that, are you breathing at all?”. Or the guy that checks every pressure gauge without asking. The higher the pressure, the higher the fame.
If you have a moderate air consumption and one member of your group sucks air like a vacuum cleaner, it can become really annoying to quit every dive in your precious vacation after 25 minutes. On the other side it can be really awkward to be the vacuum cleaner. And most divers have been there, at least in the beginning of their dive life, right?
Is a low air consumption magic?
I remember very well my first couple of dives as fresh certified PADI Open Water Diver. I did my course in Egypt, Sharm el Sheik, and my instructor did two dives with one tank, still coming out with more air from his second dive than me! I asked him but his only answer was “it´s just experience”, smiling dirty.
I had advices from another instructor that I should inhale and exhale with a slowly continous flow. But when I tried it underwater it was not that easy: Controlling the airflow from a regulator while inhaling is more difficult than you might think.
Same to exhale, at the surface it´s easy to control the airflow by opening or closing your lips, with a regulator you have to control it with your diaphragm.
Experience vs technique
My first instructor was not completely right, a low air consumption is not just a matter of experience. During my career as dive instructor I met many experienced divers with several hundreds of dives on the record, that ordered 15l tanks to be able to make at least 45 minutes in a normal dive!
On the other hand I saw divers that had on their very first try dive an air consumption “like a boss”.
How is this possible? If someone is practicing certain activities like yoga or playing a wind instrument, he might have already a very good control of his breath. The good news: You can learn some techniques to practice your breathing out of the water!
They key moment
Let me tell you the story of my key moment. As I said before, an instructor explained me that I have to control the speed of inhaling and exhaling. It didn´t really worked when I tried it on the next dive. So I slowed down by making small breaks during inhaling and exhaling, which is pretty bad as I know now.
And it didn´t worked anyway, maybe 5 bar more air left at the end of the dive.
Back home after my vacation I kept on thinking about it and then I remembered something from my childhood: As a kid I used to play trombone for a couple of years and I had to practice my breathing with an exercise, just 10 minutes every few days.
From that moment on I practiced at least once a week and before my next dive vacation every day for two weeks.
My very first dive after not getting in the water for almost a year, I surfaced with 70 bar left after 65 minutes diving – the dive master had 30 bar left and was quite surprised. I had at this time around 30 dives on the record, he 900, going out almost every day.
Before I explain you the exercise, let us talk about the different factors that influence our air consumtion underwater.
The 4 components of a perfect air consumption
A perfect air consumption depends on several factors. The more we work physically, the more oxygen is demanded by our muscles, the faster we have to breathe. Also mental stress makes us breath faster, but in that case it´s not necessary for our system.
If you have to work hard because you have to swim against a current or swim a larger distance, don´t slow down your breath too much. I made that mistake in the beginning of my instructor career. It always ended the same way: Bad headache after the dive for at least half an hour.
In that case a perfect air consumption is not necessary a very low one, it has to fit to the circumstances of the dive.
In case of stress fast breathing is not necessary and even counter productive. By focussing on your breathing and slowing it down controlled, you can reduce the stress, slow down your heartbeat and calm down.
Besides physical work and stress four more factors influence our air consumption. Three of them are affecting how much we have to work underwater, hence how much oxygen our system needs. The last one is about the ability to use just as much air as necessary.
The correct amount of weights is a crucial factor. If you carry too much you have to compensate the overweight with air in your BCD, even small changes in the depth have large effects on your buoyancy.
If you ascend a bit, the total volume increase in your jacket increases your buoyancy in total more than just a small amount of air would do. Again and slower, please! Let´s do the math to show the effect:
In your BCD is 1 liter air in 20m depth. You ascent 2m, so a decrease of 0,2 bar pressure, hence an increase of the volume of the air in your BCD of 20%: Now it´s filled with 1,2 liter. If you carry more weights your BCD needs maybe 2 liter air at 20m to compensate them, 20% increase means 2,4 liter new volume.
The same change in depth increases now your buoyancy the double! Due to that you have to compensate your jacket more often, wasting a lot of air.
On top the greater volume increases the drag of your jacket and swimming needs more physical work, more oxygen, higher air consumption.
As if that is not enough it also affects your trim because the weights are pulling down your hips while the air is pulling up your sholders, more drag, less streamlined, more physical work and so on.
Perfect trim means to be streamlined, your equipment as well as your position in the water. Your body should be horizontal, hands in front of it in more or less one line with it. If you swim in that position your body creates less drag, hence less physical effort is necessary to move. With each fin kick you glide a longer time and distance.
That results in less energy input to swim a certain distance or the same input to swim a longer one. And it looks cool when you hover perfectly horizontal while the guy next to you is kicking a bicycle and paddeling with his arms.
A perfect trim is a skill that demands some training, especially the correct fin kick techniques want to be practiced.
Another important factor to reduce the air consumption is using a perfect propulsion technique. The most important rule of propulsion underwater with scuba gear is: DON´T USE YOUR ARMS FOR SWIMMING! One stroke of your arms moves you 20 cm, costs a lot of energy and ruins your trim.
Your propulsion unit are your feet with fins, you can move in every direction if you know how to use them properly!
Do you know how many different fin kicks are existing? Check it out:
- Flutter kick – the one you learn in a normal OWD course, necessary to swim fast or against currents
- Modified flutter kick – different version used in restricted environment like wrecks, caves
- Frog kick – very efficient, useful in most situations except against currents or for short sprints
- Modified frog kick – used mostly for cavediving and in other restricted environment
- Backward kick – as the name says useful for swimming backwards. Hence useless to swim forward.
- Helicopter turn – a turn around your vertical axis just using your fins
Explaining the different techniques would exceed this article, I will come back to that soon in another blog post.
The most important fin kick you should practise is definitely the frog kick. It helps you to stay in a horizontal position and you use automatically the gliding phase after every kick. Gliding phase is the second key for an efficient underwater propulsion.
If you use the flutter kick, make a short break after every kick cycle (= each leg up and down once), stretch your legs and feet and wait until gliding almost stops, before you do the next kick. Simple but efficient, you make with the physical effort of one kick around 25% more distance.
And here we come to the part that should be very easy and is yet so hard to accomplish – breathing! We usually don´t think about breathing, it just happens because it´s a reflex. Nevertheless we are able to control our breathing to a certain level.
For a low air consumption master to control your breath you must, young padawan!
Let´s do the math again: The duration of one breathing cycle using, let´s say 5l of air (this is just a value to simplify the calculation, in reality it´s way less), can be either very short if I inhale and exhale fast or quite long if I do it slowly. Is the duration 3 seconds I will do 20 cycles in one minute, hence use 100l of air.
Is the duration 30 seconds I will do just 2 cycles in one minute and use just 10l of air. So the goal is to extend the time of one breathing cycle. You can make that experiment sitting or standing werever you are right now, it´s easy.
But the problems start when you try to do the same breathing only through your mouth. Don´t cheat and control the air flow with your lips, that doesn´t work with a regulator in our mouth!
You will see this is a little change that makes a huge effect. You have to control now the release of the air in your loungs by controlling your diaphragm muscles – which takes some practice.
Breathing techniques from other disciplines
In many different type of sports breathing is part of the training. Just look at our freediving sibblings or yoga and martial arts of all kinds. Also as I mentioned before musicians that create a tone using controlled air flow.
Now all of these people have to practice somehow to become a master and we can learn from their exercises.
I use frequently two of them that don´t take much time, also it´s not like you have to do them every day for the rest of your life.
One will help you to control the air flow with your diaphragm exactly in the way we need it for scuba diving. The other one will let you experience how you can control your state of mind by controlling your breathing.
And what are these two magic exercises?
This exercise will help to improve your air consumption by training your diaphragm.
What you need to prepare
- Yoga mat or a folded blanket
- heavy book or laptop or small board and a weight of 2kg/4 lbs
- Lay on your back on the Yoga mat or blanket, but not on your bed! It´s important to have a hard underground
- put the book/ laptop/ board & weight on your belly with the belly button as center
- find a comfortable position with your arms along your body and legs streched
- inhale slowly and deep through your nose into your belly – focus on how you lift the object with your breath
- when your lungs are completely filled, begin immediately to exhale slowly through your mouth
- your lips should be relaxed, not controlling the airflow, focus on lowering the object with your breath
- as soon as your lungs are as empty as possible, start over with inhaling
- repeat for 5-10 minutes at least 2-3 times a week and daily 1-2 weeks before your dive vacation
This was the first exercise. Pretty easy, isn´t it? I have some more, but explaining them in detail would exceed this article. If you are interested I´m working on a FREE online course where I explain all mentioned fin kicks and breathing exercises in videos!
Just sign up below for my newsletter and get access to the free online course “Peak Performance Air Consumption” as soon as it is available!
Controlling the improvement of your air consumption
If you dive frequently, do the exercise in the morning before your dives and record carefully dive time, depth and start/ end pressure including tank size.
I recommend to use a dive log app, I use Subsurface, a free open source software. You can easy configurate all information like tank size, start- and end pressure for every dive log downloaded from your dive computer.
The app uses your dive log data and the individual information to calculate for example your average surface air consumption rate, SAC.
What is the SAC and what does it show?
The surface air consumption SAC is a value to measure your air consumption per minute. As you maybe remember from your Open Water Diver course, the deeper you dive, the more air you use with every breath because of the increased density of the gas:
One breath at 10m/ 30 ft contains the double of molekules compared to one breath at the surface. The SAC takes that in count and hence explains how much air you would have used at the surface.
Example: Your dive profile shows a 5 minute descending time to your maximum depth of 20m, you stayed there for 15 minutes, went up to 16m for a few minutes and so on. To calculate your SAC you have to calculate it for each depth level, a lot of work. But Subsurface does the job for you and tells you for example an average SAC of 15l per minute.
You know already what SAC means, but what can you actually learn from it?
Understand your minute ventilation rate MV
To understand what you can learn from your SAC you need to understand the minute ventilation MV:
A normal adult has a tidal volume (volume of air inhaled or exhaled with one normal breath) of 8-10ml per kg body weight. For a 70kg diver this results in around 700ml air per breath. During a minute the same person has a respiratory rate of 14-18 breaths.
Hence the minute ventilation of our 70kg diver is 700ml times let´s say 16, which is 11,2 liter. Important: this is the average minute ventilation when your body is relaxed and calm without working. For example in the morning when you just woke up and still lying in your bed.
Every movement of your muscles will increase this rate, also stress and illness. The more you work, the more you breathe.
MV compared to SAC
Maybe you recognized it already, the SAC is basically the method to calculate your minute ventilation by correcting the pressure- related increased consumption.
Now you know that you can compare your SAC to your MV. But how you get to know your MV? The best way is to go to a specialized physician and let him conduct a test. Afterwards you will know your MV from no-work to hard-work level.
If you don´t want to pay the test and if you are fine not to have a perfect measurement, you can test yourself.
Test your minute ventilation rate at home
All you need is
- a big bucket full of water
- a transparent measuring pot of at least 2 liter volume
- a short, not too thick hose
Fill the pot inside the bucket with water and turn it upside-down that it contains no more air. Put one end of the hose in your mouth, the other end inside the pot. Inhale normaly through your nose and exhale through your mouth. Like this you exhale the air inside the pot and can read from the index how much it was.
Next step is to count how often you inhale during one minute. Start the timer with inhaling, count until one minute passed.
Multiply the number of breaths per minute with the volume you figured out before and you got your basic MV.
Understand the difference between your MV and SAC
You already figured out somehow your minute ventilation rate which is 12 liter per minute, installed Subsurface, uploaded your last dive and obtained an average SAC of 18 liter per minute.
Now you have to ask yourself why the difference is 6 liter? To answer this question it is important that you observed yourself during the dive:
- Did you use your arms?
- Where you kicking the whole time?
- Did you felt stressed?
- Did you had to swim against a current or a long distance?
- how was your breathing frequency?
Step by step improvement
If you realize that you where kicking too much and using your arms, focus on your next dive to avoid it. Compare your SAC afterwards with your dive before.
Don´t load yourself with too many tasks for one dive, just focus one particular thing you want to improve.
Best way to record your air consumption: Air integrated dive computer
If you want to control your air consumption in the most detailed way possible, use an air integrated dive computer. I had a Suunto Viper Air, which is no longer available. But a new Suunto Vyper Novo also has the option of air integration, you just have to buy a wireless transmitter.
Now your divelog data also contains the exact tank pressure at every moment of the dive. If you now make notes during your dives at what time you had to fight a current, helped another diver, tried to make a picture and so on, you can learn what affects your air consumption and improve step by step as explained before.
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