How do I improve my air consumption?

[ScottyK]

Karl_in_Calif once bubbled...




Breathe in, breathe out, relax, pause.

Thats called relaxed breathing.

In relaxed, or deeply absorbed breathing, you pause when your lungs are full. The idea is to get more oxygen out of each breath.

 

[Ender]

First, the oxygen consumption & body size:
Oxygen consumption has nothing to do with your SAC. In fact, the 5% (volume) consumed oxygen figure is more or less correct only for 1ATA. In depth, you breathe higher PO2, which translates to more molecules of O2 in the same volume - but your body can use only the same amount of O2 as on surface (given the same workload).
You'll get some more O2 dissolved in your blood stream, but the amount is negligible. (once saturated, it stays saturated and then again only the metabolized O2 gets replaced).


The volume of your lungs has a lot to do with SAC, as it pretty much directly affects how much air you'll get through.
That's one of the reasons comparing SACes between any two people (bar identical twins maybe) doesn't make much sense. Someone with 3L VC will have way smaller SAC than someone with 6L VC - assuming all other things being equal.

I have above average lung capacity (6.2 litres VC, when my predicted is 5.something), and my SAC is quite up there - about 21LPM when working in our cold currenty waters. It can go down to about 14 on a relaxed dive, but I plan my dives with 20. I am not exactly a new diver (around 170 dives in last two years).

So, saying someone's SAC sucks (compared to others) is like saying that they suck because they can't bench press 100kgs. It can be easy for someone, and impossible to ever achieve for someone else.

What I'd do in your place is to log my SAC over few tens of dives to watch for improvement, and try to find my Tidal Volume so I'd have some baseline for SAC.

Regards,
Vlad

 

[E-Boat]

Try this i see you guy say it take you about 9 ro 10 sec to exhale. Try humm a song. That what i usually do. I should be slow song. That way it take me almost 20 sec to Exhale.

 

[davehicks]

You have said a couple of times that you remained at 70-80' the whole dive. Frankly, I'd be suprised if you did manage more than 30 minutes if that was your average depth. If one is doing a deep wreck or reef dive in open water, this seems very typical. Descend, spend the entire time at depth, do a direct ascent.

If you are diving on some sort of wall or sloping terain, then you really should start deep and start making a slow, smooth ascent after 15 minutes or so at depth. This is a much safer profile and since you don't spend the entire dive at max depth you will be using a lot less air.

If you can upload a dive profile from your computer that might help to fill in the picture. Maybe you can calculate your SAC as well.

I don't think you mentioned how many dive's you done either. Experience helps a lot with air consumption. Also you sound really acitve and animated. Maybe a little too animated under water? I see a lot of people just starting out that are in constant motion while diving. Arm movements, kicking, and generally spastic. Try relaxing and just going with the flow. Let the current do all the work and take in the sights.

And finally, in the word of the master, "This is only an exhibition, not a competition; No Wagering!!"

Dave

 

[knobber]

guys, thanks so much for the help. I think one of you may have keyed in on something I didn't take into effect--trim. I have a back inflate with rear trim pockets (mares jubilee), and I DO remember my feet staying higher than my body. I actually kicked my feet a couple times on my first dive thinking that maybe there was some air trapped in there causing them to rise. I had 12 lbs in the IW, and four pounds in the trim. I guess I should go to a calmer lake and mess with the trim amounts.
The weight wasn't a problem--I was at the minimum that would cause me to sink in salt water with a 3mm wetsuit.
I guess the other factor was that I just don't have that many dives. Although the trim wasn't causing me to flop around to stay level (I just ended up diving with my feet higher than my head, which seemed better since I could get closer to the corals w/o worrying about stepping on any), I guess I may have subconsciously been kicking more to stay in a level position.

I was just frustrated that an out of shape--yet experienced--diver who hadn't dived in over a year was outlasting me by 20 minutes, and he only weighs about 10 lbs less than me. So now I'm going to look for some info on trim. If I don't find much on here, I may be asking for some more help!

Thanks all

 

[LilmanHSU]

You are quite correct ScubaCollin,

When I first started diving, I sucked down the air like I had moments to live..

My instructor was impressed by the fact that I consumed a bottle and a half of AL80's in the pool session over 4 hours! And that wasn't continuous usage.. We guessed it was nerves..

Now I average 35-45 minutes per dive at around 40-60 feet depending on conditions.. Its not fantastic, but its an improvement.. I am taking my AOW class right now, and I intend on talking to an instructor about getting into Peak Performance Buoyancy to aid in making my bottom time better.

FYI.. I'm 5'11 163

-Paul

ScubaCollin once bubbled...
I dont know if youre new at diving or not, but correct me if im wrong, air consumption should get better with experience.

 

[bottom_sucker]

I was also a maximum air hog in the early days. I managed to get it to a more reasonable level by dropping weights, practicing bouyancy control, taking more time, paying attention to breathing.

However, the biggest improvement I achieved was when I got new screens in my reg! Might not hurt to have them checked....

Dave

 

[VTernovski]

nobody mentioned what types of fins you use. I used to use a lot of air with my stiff and big Mares Quadros... I switched to Dacor Black Tiger, and saw animprovement, finally, I sitched to 98% of stricktly frog kicks on ScubaPro Jet Fins (size XL), and saw a drastic improvement in my air consumtion. From now on, I try to use frog kick most of the time if not all.

 

[Karl_in_Calif]

Northeastwrecks once bubbled...
Isn't it true that skip breathing can cause a dangerous buildup of CO2, resulting in an increased breathing rate or, if the skip breathing continues, unconsciousness and death?

I have a friend who posts on this board. His equivalent surface RMV is under 0.5 cu ft per min. He finishes most of his dives with headaches. Clue.

Headaches is the primary result of skip breathing, that I have seen.

The technical diving literature warns about skip breathing on technical dives. Deep water black out is possibly the result of skip breathing then. If that meets your definition of dangerous, then you are probably right.

 

[LilmanHSU]

I use Scuba Pro Twin Jets.. Very easy fins to swim in.

VTernovski once bubbled...
nobody mentioned what types of fins you use. I used to use a lot of air with my stiff and big Mares Quadros... I switched to Dacor Black Tiger, and saw animprovement, finally, I sitched to 98% of stricktly frog kicks on ScubaPro Jet Fins (size XL), and saw a drastic improvement in my air consumtion. From now on, I try to use frog kick most of the time if not all.