Improving air use in currents

[nolatom]

Current burns up your air the most if you have to swim against it. If you're on a wreck, depending on the local rules, you can "cheat" and use your hands to "grab, pull, and glide" while your legs and lungs get some rest. It's hard on your gloves but they are a happier problem than running low on gas and getting anxious over that and breathing harder, a cascading problem that can get serious real fast. Obviously do not grab or touch coral, or especially urchins ;-) but pulling yourself upcurrent is one way to get upcurrent, as long as you respect the marine life, which on the average wreck is fairly easy.

 

[industrious95]

One good technique, if your not following a group and have the freedom to choose your own path, is to avoid the current. If you're swimming on a wreck and the current is hitting it on the port side, go against the current on the starboard side, then with the current when you return on the port side.

Sometimes current is strong at the surface and weak on the bottom, sometimes visa-versa. Sometimes neither. Adjust your depth to take advantage of that.

Having a rope or structure to pull yourself along saves a lot of energy.

Finally, a good rule is to always begin your dive INTO the current, so when you're ready to return to the boat, you're not fighting the current when you're tired.

As to your concerns about being "the first guy to run out of air and force the group to return," just remember that somebody is going to be the first to run low on air, there's no shame or dishonor if it's you. It's not a contest, it's a recreational dive for pleasure. Also, plan the dive on the surface, find a buddy who consumes air at a similar rate as you.

 

[mrdre]

No, it is an anecdote. Similarly it is also anecdotal that I know divers who smoke like chimneys who sip air and can outlast anyone else I know on any given cylinder size.

Actually both are not anecdotes. Athletes develop large muscles and lungs and are used to using all the lung volume.

It's not anecdotal about divers who smoke like chimneys either. If the diver is very young (just like the guy "that I know of"), who was diving since 12, and was diving every other day, and started smoking recently, then the smoking didn't cause YET that much damage to the lungs. Also he is a very skinny and small guy. Of course you could say that "if he didn't smoke, he would be much better" - with that I would absolutely agree.

 

[TMHeimer]

Current burns up your air the most if you have to swim against it. If you're on a wreck, depending on the local rules, you can "cheat" and use your hands to "grab, pull, and glide" while your legs and lungs get some rest. It's hard on your gloves but they are a happier problem than running low on gas and getting anxious over that and breathing harder, a cascading problem that can get serious real fast. Obviously do not grab or touch coral, or especially urchins ;-) but pulling yourself upcurrent is one way to get upcurrent, as long as you respect the marine life, which on the average wreck is fairly easy.

Yeah, pulling yourself along by grabbing rocks is something I regularly do. You can probably go about as fast as if you were finning. It is also a great method to prevent cramps or to get somewhere safe (3' deep) if you have them. Of course there have to be appropriate rocks present.

 

[BRT]

I've seen this theory posted here before, and if there's anything to it, it certainly is "Strangely enough ...". Can you post a link to any articles that back this up?

I certainly can't quote studies done, but some of the lowest air usage people I've dove with were not skinny athletic types. I kind of think those athletes have the ability to get more work done than I do, and converting food to work requires a bunch of oxygen! Maybe the fat people must, of necessity, learn how to do things more efficiently???

 

[Hickdive]

Actually both are not anecdotes. Athletes develop large muscles and lungs and are used to using all the lung volume.

It's not anecdotal about divers who smoke like chimneys either. If the diver is very young (just like the guy "that I know of"), who was diving since 12, and was diving every other day, and started smoking recently, then the smoking didn't cause YET that much damage to the lungs. Also he is a very skinny and small guy. Of course you could say that "if he didn't smoke, he would be much better" - with that I would absolutely agree.

The plural of anecdote is not data.

I do not know of any studies published in any peer-reviewed paper that demonstrate these anecdotes to be true. Perhaps you do; in which case please give us the links. Until then the fact that "I know" divers who smoke with low SAC rates remains an anecdote.

 

[oszillodrom]

I would expect the ideal body for low air consumption would to be one with low muscle mass, efficient use of oxygen (high aerobic capacity) and a low heartrate, in other words, a long distance runner or similar. Only thing that could work against them is increased lung volume.

 

[Iralub]

Thanks very much for all the excellent advice.

Trim and kicking styles I definitely need to work on. I do have difficulty staying perfectly horizontal, with a tendency to have a more head up position (although buoyancy itself appears to be mostly ok). Maybe with tank hanging down pretty low vis a vis my body (short torso) and weights unbalancing me?

Good to know that I don't need to achieve a super fitness level to improve

 

[MXGratefulDiver]

Thanks very much for all the excellent advice.

Trim and kicking styles I definitely need to work on. I do have difficulty staying perfectly horizontal, with a tendency to have a more head up position (although buoyancy itself appears to be mostly ok). Maybe with tank hanging down pretty low vis a vis my body (short torso) and weights unbalancing me?

Good to know that I don't need to achieve a super fitness level to improve

Reasonable fitness certainly helps, but you don't need to be athletic. Work on the trim, adjust your tank position and weights so that they don't have a tendency to make you foot heavy ... think about the fact that when your feet are down you necessarily have to maintain a lightly negative state of buoyancy to compensate for where your kicks want to take you (slightly up every time you kick) ... and what that does to the amount of work you have to put into your diving. This is by far the biggest change most divers can make when it comes to improving air consumption.

And don't neglect how you think about diving. Many divers seem to be in a hurry to get somewhere ... and the faster you kick the more air you're going to consume. The easiest way to overcome that tendency is in how you think about your dive ... are you really in a rush to get somewhere? Once you're in the water you ARE where you want to be. Swim slowly, look around, and enjoy the sights before your eyes. It's way more relaxing, and not only will your air consumption improve, but you'll see more. It's amazing how often I've seen people swim right past wonderful things to look at because they were swimming along too fast. Some of the coolest critters in the ocean are excellent at camouflaging ... but they're easy enough to pick out if you give your brain time to process what it's seeing.

Finally, just dive ... most of us improve our air consumption as we gain experience. My OW instructor told us to give it about 50 dives to begin to learn how to relax. I found that to be pretty spot on ... prior to that point my dive buddies used to tease me that they could see the sides of my tank move when I breathed. But after about the first 50 dives or so I noticed a continuous improvement in my air consumption as I started to feel more relaxed underwater. I think that's generally true for most people.

... Bob (Grateful Diver)

 

[RJP]

Anything and everything you need to know to improve air consumption (in currents or otherwise) comes back to two key things from a physiology standpoint:

1.) Air (O₂) consumption is a DEMAND function
2.) Air (O₂) is consumed in your body's muscle cells, not your lungs

Accordingly the most effective way to reduce your O₂ consumption is to reduce the DEMAND that the muscle cells in your body have for O₂. There are 13 key "Demand Reduction Strategies" that any and every diver can employ to improve their O₂ consumption:

1. Slow down
2. Get more comfortable in the water
3. Slow down
4. Get your weighting fine-tuned
5. Slow down
6. Get your horizontal trim dialed-in
7. Slow down some more
8. Stop swimming with your hands and arms
9. Slow down even more
10. Utilize efficient kick styles
11. Just a little bit slower... please?
12. Streamline your gear
13. Slow down - you're still moving too fast!

OK, now that we've addressed the best ways to improve your air consumption rate, let's talk a little bit about how a diver should breathe...

There is much advice here on SB about reducing your air consumption by controlling/modfying/focusing on your breathing rate. I won't add anything to those points, other than to say that an awful lot of that advice is largely inaccurate. Let's use a car analogy:

Muscle cells (where O₂ is burned) = cylinders (where gas is burned)
Circulatory system (delivers O₂ to muscle cells) = fuel injectors (deliver gas to cylinders)
Lungs (delivers O₂ to the circulatory system) = gas tank (delivers gas to fuel injectors)
Regulator (delivers O₂ to the lungs) = Pump at gas station (delivers gas to car's gas tank)
Scuba tank (where reg gets O₂ from) = Storage tanks at gas station (where pump gets gas from)

Suggesting that you can meaningfully improve your air consumption by controlling how often, how much, and how slowly you put air into your lungs is like suggesting that you can improve your car's gas mileage by reducing the number of times you purchase gas, always filling and emptying the tank completely, and pumping the gas into your tank slowly. Those are all SUPPLY strategies... but remember, O₂ consumption is a DEMAND function. (Note - for simplicity of this post, I'm not addressing the "exhaust" portion of the equation, since the question was about "consumption.")

Now, before anyone bites my head off, I'm not saying that things like breathing rate, speed, and depth are absolutely unimportant. I'm merely point out the fact that - just like our car analogy - assuming we don't try to deliver more or less O₂/fuel to our muscle cells/cylinders than they DEMAND everything will be fine. Sure, if we don't deliver enough - or deliver too much - O₂/fuel our "engine" will run rough and waste some fuel. But if our lung/gas tank function is within a normal range... our body/car will run fine and we don't need to worry about these things.

Accordingly, I will politely disagree with people who say "focus on your breathing at all times" or those who will offer advice about how many seconds to inhale and how many seconds to exhale and the like. My advice on breathing rate, depth, etc is as follows:

1. Breathe normally
2. If there is a problem causing you to breathe abnormally, fix the problem
3. Breathe normally
4. STOP focusing on how you're breathing!
5. Breathe normally
6. Ensure that the 13 "Demand Reduction Strategies" listed at the top of this post are second nature, so you can STOP focusing on those things too! (Plus, reducing your body's demand for O₂ will help ensure that you are breathing normally!)
7. Focus on your dive - that's why you're underwater

Best regards - Ray

Ray Purkis