Lowered my SAC, got a free headache

[Castor]

I tried to manage SAC by concentrating on it and ran into similar issues - btw, I was an air hog. Practice will make it get better. I became more relaxed in the water and stopped being tense about my breathing.

And lo, the SAC dropped.

Honestly, when my dive buddy and I became so comfortable with each other that people thought we communicated through voodoo or telepathy was when the great breakthrough came for both of us. Of course, he has moved 2000 miles away. I wonder what will happen to my gas usage now?

 

[ClayJar]

Trying to lower your SAC is a classic example of treating a symptom while ignoring the cause.

I have never tried to reduce my air consumption. Rather, I have concentrated on technique and merely used my calculated SAC as a barometer of my progress. When I fixed my trim, I used less air. With added experience, I've also seen a gradual improvement, although not anywhere near that provided by trim.

Trying to improve your SAC without addressing the root cause is like trying to be less sore after a hike by hopping on one foot the whole way.

 

[serambin]

Can you get a high enough level of CO2 to cause a headache while diving? Wouldn't the CO2 level cause you to suck enough air to off gas the extra CO2? Rapid shallow breathing causes hyperventilation, purging too much CO2, doesn't it?

Stan

 

[Warren_L]

CO2 retention unfortunately can occur quite easily if you're working too hard or breathing inefficiently. Rapid shallow breathing will only serve to exacerbate the situation as shallow breathing creates a lot of dead airspace which, if not allowed to clear, will contain exhaled CO2 which will only be re-inhaled. The manifestations can begin with symptoms such as headaches, nausea, blurred vision, amongst others and progress from there. If severe enough, unconsciousness can occur, which is not good underwater.....

 

[thomjinx]

As spectrum said, breathing deeply makes a big difference. Slowly and deeply is what works for me, and I never get a headache from it. I am not sure exactly what my SAC rate averages, but I seem to use less air than everyone else, with the exception of very petite ladies.

 

[TSandM]

As everybody has said, breathe deeply and rhythmically, like what's taught in yoga, and don't focus a lot on your breathing itself.

Air consumption drops as you become more comfortable and relaxed underwater, and as your technique improves. As Cameron's article no doubt states, trimming out horizontally, avoiding swimming with your hands, moving slowly through the water, and using an efficient kick will all reduce your gas consumption without you having to think about it at all.

New divers use more gas. You are diving what are really VERY small tanks, and I'd highly recommend renting either LP 95s or HP 100s instead of the 80s you've been using. That will give you enough gas to complete a dive with anybody without worrying about being an air hog, and getting rid of the worry will do a lot in and of itself to reduce your gas consumption.

And you're doing the most important thing you need to do to get more efficient in the water -- You're out there diving!

 

[Web Monkey]

On a dive this weekend I spent a lot of effort on improving my air hogging ways. I did succeed in lowering my SAC from the usual 0.8-0.9 to 0.6. I also found that I had a headache at the end of the dive, presumably from CO2.

My buddy, an experienced local that I was diving with for the first time, suggested taking a normal breath but then exhaling slowly--not making inhale and exhale slow. Any other tips?

Sure....

You're working the wrong end of the equation.

The only reasonable way to improve your SAC is to burn less oxygen. You can do this by relaxing and doing less actual work.

Improving your trim and finning and doing less work in general should get you down to the .5 - .7 area depending on whether you're diving wet or dry and how much stuff you're dragging around with you.

Another possibility is that you could just get bigger tanks. There's nothing magic about an 80, and there's no shame in breathing. Bigger people just use more air than smaller people. I could train for the rest of my life and never use less air than the 90 pound girl who was in one of our classes.

Terry

 

[LowVizWiz]

Hey Matt!

I feel your pain, I'm also an air hog. I was averaging .7 and .8 on very shallow dives.
But as rawls points out your size may be your isssue althought you don't mention your stats. I'm 6'5" so my sac was always higher than those how dove with me no matter what.

What helped me the most (My average now is .6) was getting the proper amount of weight for me.

As a matter of fact, if I'm a little lighter than I need be, I consume less air. I may have a harder time holding a safety stop at the end without a line, but it's something I'll consider doing if I know my air consumption will be the limiting factor to the dive.

 

[Charlie99]

Learn how to make diving easier. Work less, use less energy, generate less CO2. Only then can you breathe less.

It is also important to breathe efficiently. Deep breathing lessens the percentage of dead space -- with shallow breaths you are just recirculating the same air back and forth.

My experience with helping many different divers (often just insta-buddies met that day) is that learning how to be truly neutral, and being able to stop finning at any and all times and stay at the same position in the water column makes a huge difference in SAC.

Charlie Allen

 

[tc]

Like I said- Relax!