Top Tips for Improved Air Consumption
Ask the question 'How do I improve my air consumption?' in any dive-related forum and you will get a series of standard answers: be physically fit, be correctly weighted, have good buoyancy control and trim, wear the right kit, move slowly, remain calm. All of these things will certainly help, but without correct breathing technique, any improvements in air consumption are likely to be modest
During my first holiday as a certified diver, I was the person who would run low on air first. Over the next few days, I became increasingly embarrassed, apologising to the other divers, whose platitudes of 'don't worry' seemed to become increasingly short. I was very, very grateful when a diver with worse air consumption than me joined the group. Now that he was taking all the stick, the other divers were more candid in front of me, and I realised how frustrated they had been with my poor air consumption. I decided to take my AOW course and asked my instructor how to improve my air consumption.
The answer is right there in the Open Water manual: 'always breathe slowly and deeply and continuously when using scuba.'
I find that while most divers know that this is the correct way to breathe, many do not really understand why it should be so, and it is often not properly explained by instructors. Consequently, the quest for better air consumption is something that often lingers long after a diver has taken control of their buoyancy and become comfortable in the water.
Going back to basics - most people will know that when we inhale, we take oxygen into our lungs which our body uses to turn the nutrients we eat into energy. The waste product of this process is carbon dioxide (CO2), which is returned to the lungs by the circulatory system, and which we dispose of by exhaling.
What a lot of people don't know is that the breathing cycle is triggered by a build-up of CO2 and not a lack of oxygen. It is important, therefore, that we efficiently eliminate as much of the waste gas as possible. Failure to do so means that the CO2 remains within the 'dead air' spaces of our respiratory system - primarily the trachea (windpipe) and the bronchi, the tubes which connect the trachea to our lungs.
Since the first thing that enters our lungs when we inhale is the dead air, it's important that it contains as little CO2 as possible. If we don't exhale efficiently, then the next breath we take will have an artificially elevated CO2 content, which will trigger the subsequent breathing cycle earlier than it should be, and we feel the urge to breathe again. If this cycle is repeated continuously, we start to breathe more rapidly. It seems a bit odd, but as a result, breathing quickly makes you breathe even more quickly. Underwater, this can lead to a feeling of suffocation, which can rapidly turn into panic.
Breathing rapidly is inefficient partly because the trachea and bronchioles are not smooth. They are supported by rings of cartilage - a bit like a bendy snorkel - and rapid breathing creates turbulence within the trachea, leaving CO2 trapped within the dead air spaces. A good analogy is breathing through a snorkel that has a bit of water in the bottom. If you inhale too quickly, the turbulence created pulls the water into your mouth. Breathing slowly and smoothly ‘past’ the water will prevent this from happening, and a similar technique should be used when breathing compressed air underwater.
There is no single breathing pattern that would suit all divers - we come in many different shapes and sizes. I have heard different ratios given for inhalation to exhalation timing, but in my experience as a dive professional, a five-second inhalation followed by a five-second exhalation - both at a continuous rate - worked exceptionally well. It's a technique I used to improve my own air consumption and also taught successfully to students and other divers. The exact timing will vary between individuals, but it's a good place from which to start and build your own rhythm. Breathing slowly, deeply and smoothly is the key to improved air consumption.
When it comes to how 'deeply' you should breathe, the phrase leaves rather a lot of room for interpretation. You shouldn't completely fill or empty your lungs as this can have a detrimental impact on your buoyancy control. Although it’s impossible to measure, imagine breathing between one-third and two-thirds of your lung volume with each cycle.
For Star Wars fans, an analogy that works surprisingly well is to imagine you're breathing like Darth Vader. The iconic hissing was, after all, a sound effect generated by a scuba regulator.
It takes practice, and more diving, to properly get the hang of the technique, but there are other factors you can take into consideration when it comes to improving your air consumption. Remember that you breathe more gas the deeper you dive – at 10m you are already breathing twice the air you would at the surface, and four times as much by the time you get to 30m. Where possible, and if it's safe to do so, shallow up with your buddy early in the dive and enjoy the extra time you get below the surface.
When you're out of the water, the visualisation approach can be of immense benefit. Finding some time to yourself and practising your breathing will help to instil the technique in your mind. Many yogis find that breathing techniques taught through yoga are equally beneficial (although you can also practise without bodily contortion!)
Fitness, correct weighting, buoyancy control, appropriate gear and remaining calm are still important, and although none of them is the definitive answer to improving your air consumption, each plays an essential part.
On an easy recreational dive, it's possible for an unfit person with good breath control to have better air consumption than a very fit diver with poor breath control. One of the worst cases I ever saw, in fact, was an Olympic-class marathon runner who managed to inhale 150 bar of a standard 12l tank in 12 minutes. But regardless of technique, an unfit person will struggle against even a moderate current, so being in reasonably good shape is important for maintaining control of your air supply. You should be able to walk a couple of miles and mount a few flights of stairs without huffing and puffing, but if you start wheezing trying to reach the top shelf of the snack cupboard, then you need to re-think your life choices.
Weighting, Buoyancy and Trim
Although you can have good buoyancy control and still breathe too quickly, good air consumption is virtually impossible without good buoyancy control, and good buoyancy control starts with correct weighting. An overweighted diver needs to continuously add and remove air to their BCD, will often take rapid gulps of air and keep finning to keep themselves off the bottom. An underweighted diver (or one who hasn't properly deflated their BCD) will constantly fin downwards to stay underwater. Make a proper weight check and remain as horizontal in the water as possible - streamlining reduces the drag on your body and equipment meaning you expend less energy swimming.
BCDs and exposure suits that are too tight prevent you from breathing properly and therefore are detrimental not only to good air consumption but also safety. Make sure you have adequate exposure protection for the temperature of water in which you are diving - getting cold underwater will dramatically increase your rate of breathing.
Some fins are better than others at dealing with current and particular finning styles. There's no one-style-fits-all solution but novices can't go wrong with a bog-standard paddle fin. More often than not, however, excess energy expenditure when swimming is down to poor technique. A lot of snorkelling can help.
Regulators need to be properly maintained and serviced - if they become too difficult to breathe from then it will affect your air consumption and may prove dangerous. Venturi assist controls (sometimes marked 'dive/predive' or '+/-' are there to stop regulators free-flowing at the surface and will not affect the amount of air you actually breathe. Many regulators also have a 'flow control' which changes the rate at which air is delivered to the second stage. These also do not affect the amount of air you breathe, but some divers (myself included) like to set it so that there is some slight resistance to breathing. I find it helps maintain my breathing rhythm, but it's more psychological than physical. Set too low and it makes you work too hard and set too high it can cause the second stage to leak during inhalation, in which case you're losing air from the tank, even if your breathing is under control.
Whether you lose your nerve because of poor conditions or get excited by a passing whale shark, it's important to remain calm to preserve your breath control and air consumption. Rapid breathing can quickly lead to panic so if you find yourself nervous and breathing heavily, communicate with your buddy or guide, monitor your air supply, signal that you have a problem and need to slow down while you regain control of your breathing. Head for shallow water if possible, abort the dive if necessary and make sure you debrief thoroughly back on the surface. You might realise that you had nothing to worry about in the first place.
Improving your air consumption rarely happens instantaneously and it takes some perseverance and perhaps a little discipline to get it right. Do not beat yourself up if your air consumption is not where you want it to be. There are thousands upon thousands of divers who've been labelled 'air hogs' and suffered in silence. Talk to your buddies, perhaps ask them to try some easier dives while you get in the practice; do not be afraid to talk to your guides and instructors if you're diving with a group of unknown people on holiday somewhere. Knowing in advance that somebody might be quicker to run through their air than others helps with dive planning and - importantly - group safety. It is nothing to be ashamed of.
The best way to master the art of diving is, after all, to go diving.