How Much Air?

[Mr Carcharodon]

Do a search on here or min gas or min deco. That is the least amount of gas needed to get you and a buddy to the surface in an emergency. This is a variable value and will depending on the depth at which the emergency occurs. Generally you will plan for the deepest point in your dive, and then back off as you ascend. For deeper dives you may find you need a larger tank(s) for the dive you are doing.

 

[dmaziuk]

My problem is my tidal volume is 650 to 700 mL because of my size and lung capacity. That is better than 30% more air per breath. Being a respiratory therapist I have done many pulmonary function tests on myself.

Earlier this week I was on a group dive where I came up with something like 500 or 800 psi and this lady came up with 2000. I can move less and get my breathing rate down etc., but I have these swimmer's lungs that may well be longer than her torso. There's no way I will be able to match her SAC ever.

 

[ZzzKing]

She was probably cussing under her breath about the Hoover that cut her dive short.

 

[TMHeimer]

I'm sure you know the faster you swim the more air you use. Once in a while I really want to get somewhere fast, and am still amazed by how much the needle drops.

 

[Derffie]

Thank you all. Yes, I do have busy brain. Clearly, I need to work on my breathing topside. Also, lose some lead and swim more efficiently. Not all that easy to work on this an accrue more dives as we live in Chicago. So, there's the quarry....

 

[Reku]

quarries are the best places to hone your skills!

 

[scubadada]

Thank you all. Yes, I do have busy brain. Clearly, I need to work on my breathing topside. Also, lose some lead and swim more efficiently. Not all that easy to work on this an accrue more dives as we live in Chicago. So, there's the quarry....

I'm not sure you can practice your breathing while not diving. Breathing on scuba is about the opposite of breathing on land. You usually take a breath naturally, exhale, and pause a little before taking your next breath. Underwater, you take an unnaturally larger and slower inhale, pause for a little while, and then exhale slowly. Breathing on scuba does become completely natural, I do not have to think about my breathing underwater.

Your SRMV/SAC will improve by working on all the things that have been mentioned, and, simply, by more diving and experience

 

[Ozwald]

Just a thought but could it be that you have your hand on the button possibly too much? By this I mean on the inflator? As a newer diver the constant air in/air out trying to achieve proper buoyancy can blow through gas pretty quick. As others have mentioned this all has to do with buoyancy control which will come over time. Other than that, relax....your air consumption will go down as you dive more, don't overthink it.

 

[MXGratefulDiver]

When I was a new diver my buddies used to tease me that they could see the sides of my tank move when I breathed. My nickname was "Shop Vac". Even when I brought the biggest tank in our group, I was always the first one to have to turn the dive because of air consumption.

It gets better. Just dive and stop worrying about it. You need what you need. As your technique improves, as the excitement wears down a bit, as you learn to slow down your movements to maintain your desired position, your "city miles" will turn into "highway miles", and you won't be burning through your gas so fast.

Most of us go through the same cycle, so I'm sure your dive buddies understand ...

... Bob (Grateful Diver)

 

[yle]

30 second exhales? Less than 2 breaths per minute? Air consumption related to busy brain?

I know a 30 second exhale might seem amazing to a lot of divers (yourself included, apparently) but it's a de-facto requirement for certification with PADI. All of my OW students do this effortlessly, after a bit of practice.

As for the "busy brain" issue... I apologize if my description of "busy brain" confused you, but task overload does tend to increase respiration rate. I was referring to the fact that new divers, or divers playing with new equipment (especially cameras), tend to have higher respiration rates because their brains are working on too many things at once. This is based on personal observation (me observing other divers...), so I tell new divers that their air consumption will improve as they get more comfortable with their diving. Of course buoyancy control plays a significant role in that comfort also.

Again, I apologize if my original post was too confusing for you.