Okay, in case you’re wondering how your dive professional can stay very long underwater and still have a hefty amount of air after 1 hour dive?! Here’s some way you can improve your air consumption while you’re diving!
You heard this a lot from your instructor when you’re learning how to dive. Probably the most important factor on how you can improve your air consumption while you’re diving. Being relaxed, no jerky movement, reducing your workload will reduce your air consumption vastly.
Don’t use your hands – use your fins. That’s probably the most ineffective way to move underwater; you’ll end up using more energy and consume more air. (Exception here of course if there’s physical limitation to finning.)
Remember that your body conducts heat away 20 times faster while you’re underwater. Wearing a rash-vest is nice in warm waters (and less hassle compare to wearing wetsuit) but after 2-3 dive a day you might feel a little bit cold and you’ll use more energy. Make sure you stay warm during the dive.
Streamlined your equipment
When carrying spares put it in pockets and try to minimize dangles around your equipment. Dangling equipment create more drags while you’re underwater. If you don’t need a light on the dive, keep your torch away, put spare mask or reel in the pocket, , streamlined long hose, get a foldable snorkel so you can put it in your pocket, etc.
Always being exactly neutral is the key. If you’re not, if you’re slightly heavy or light, you’re constantly using fin power (and air) to maintain a constant depth. If you’re not neutral, you can’t glide between fin strokes.
Minimize the lead
When you’re too heavy underwater. You need to pump more air to gain neutral buoyancy. Imagine the amount of effort you have to make with an extra gallon of air in your jacket in the water.
Any oxygen taken from your tank but not absorbed into your bloodstream is wasted. That’s the case when you take short, shallow breaths. A large part of the air you take in fills your throat and bronchia, but doesn’t reach your lungs before it is expelled again. You have to take another shallow breath sooner because you didn’t get much benefit from the first one, and a lot of air is wasted. Instead, try to inhale deeply, filling your lungs completely with each breath. A deeper breath brings air to more of your lungs’ tiny “air sacs” (the alveoli) where gas exchange takes place. It also adds more fresh air to the volume of “dead air” that remains in your lungs, throat and mouth from the previous breath, so the mix is richer. When more alveoli are more fully inflated with fresher air, gas exchange is more efficient: More oxygen is extracted from the incoming air and more carbon dioxide is released. Although each breath uses more air, you will take fewer breaths, and the net effect will be that less air is used. Short, shallow breaths are more frequent and less efficient. Exhale fully too, so you expel as much carbon dioxide as possible. Anything not exhaled is carbon-dioxide-heavy “dead” air. On your next inhale, that dead air–instead of fresh air–partially fills your lungs. The urge to take the next breath is triggered not by lack of oxygen but by excess of carbon dioxide, so you find yourself inhaling again sooner. On the other hand, a deep exhale extends the time before you feel the need for another breath.
You consume considerable energy just by breathing, by sucking the air in and pushing it out again. To inhale, you have to suck open a demand valve in your second stage and pull gas down your throat and into your lungs. Each inch along the way and each corner the gas stream turns mean friction and turbulence. Both increase the effort you put out in just breathing and decrease the amount of gas that actually gets to your lungs. Friction and turbulence are unavoidable, but the amount goes up dramatically when you try to breathe quickly–just as a faster-moving boat creates a bigger wake. The problem gets worse as you go deeper because the gas is thicker–it’s like trying to suck a milkshake instead of water through a straw. So don’t force it. Try for a long,
slow inhale until your lungs are full, then a long, slow exhale until they are empty. More air will get to your lungs, it will spend more time there exchanging “good” for “bad,” and you will use less energy pushing the air back and forth.
Get in shape
Two people climb a flight of stairs. At the top, one is huffing and puffing and the other is breathing normally. The heavy breather is getting more oxygen, but he’s wasting a lot of what he inhales because he’s breathing so rapidly there isn’t much time for gas exchange. It’s an adaptation that makes sense only on land where the air supply is unlimited. Diving can be surprisingly strenuous because water is so much denser than air. Swimming into a current, it’s not difficult to elevate your breathing to the very wasteful rate of huffing and puffing. But even much lower levels of exertion will cause your breathing rate to rise. How much it rises and how soon depend mostly on your aerobic conditioning. A diver in better condition will have less increase when the workload goes up, so he will use less air. The other part of getting in shape is to lose fat and achieve a more streamlined shape.
Do more dives!!
Inexperienced divers are famous for burning through their air supply at a furious rate. The reason is anxiety. A new diver is understandably nervous, and his body’s automatic response to danger is to raise his metabolism, his heart rate and his breathing rate. It’s hard-wired, the body revving its engine to be ready for fight or flight, though the result is a lot of air cycled through his lungs but never used, just dumped into the ocean. You may not be a new diver, but unless you dive almost every week it’s still an unnatural activity, and your body isn’t as happy as you are about putting its head under water. Dive more–your body will get used to the idea, and you’ll breathe less. Don’t feel bad when you be the first person to be low on air; remember that your divemaster/instructor have hundreds of dives and they probably dive everyday.