Air consumption

[mridude]

I know this has been talked to death, but still...

I have around 100 dives all in Cozumel and I am AOW cert. Recently I dove one week with other divers that have been diving 30+ years. They were all very big men. My dive buddy and I are both very fit. My buddy watched me dive and says I rarely move a muscle except of course when I need to fin. my hands are always clasped or folded and arms tucked close. Nothing hanging from my wetsuit. In other words my trim is good. The more experienced divers have their hands outstretched or out to the sides or basically just whatever they feel like doing. They are as or more active as I am. In fact a couple of them were zooming around with giant cameras making sure to get in everyone's way to "get the shot". We were all on nitrox. They all consistently use less air! I was up 10 to 15 minutes earlier every time. (about an hour total most dives). I think I dive fairly relaxed. I cant figure out why I am using more air!

 

[Lorenzoid]

Don't sweat it. You seem to be doing everything right. I think it just comes with practice/experience. You can get all the advice in the world, and while some of it may help, nothing will help as much as simply getting more dives under your belt. I think I had well over 100 dives before I noticed my air consumption decreasing substantially.

One thing that I found interesting was that the more I let thoughts about air consumption enter my head during a dive, the worse my air consumption was. When I stopped thinking about my air consumption, it started improving.

 

[archer1960]

Are you using the same size tank as they are?

 

[Diver0001]

I know this has been talked to death, but still...

I have around 100 dives all in Cozumel and I am AOW cert. Recently I dove one week with other divers that have been diving 30+ years. They were all very big men. My dive buddy and I are both very fit. My buddy watched me dive and says I rarely move a muscle except of course when I need to fin. my hands are always clasped or folded and arms tucked close. Nothing hanging from my wetsuit. In other words my trim is good. The more experienced divers have their hands outstretched or out to the sides or basically just whatever they feel like doing. They are as or more active as I am. In fact a couple of them were zooming around with giant cameras making sure to get in everyone's way to "get the shot". We were all on nitrox. They all consistently use less air! I was up 10 to 15 minutes earlier every time. (about an hour total most dives). I think I dive fairly relaxed. I cant figure out why I am using more air!

In a word... experience. My air consumption continued to fall for about my first 600 dives, at first dramatically and then marginally after that. Now I use about as much air during a dive as I do when sitting on the couch watching the discovery channel.

In other words, it sounds to me like you're doing everything right. Just let it go and you'll get to where you want to be.

That said, everyone has a lower limit. My air consumption is pretty good but when I dived with TSandM I was humbled. She's tiny and uses about 1/2 as much air as I do. My best mate's girlfriend is like that too. She has about 200 dives, I have about 10x that..... but she uses less air than I do. Sometimes it's just a matter of how big you are.

R..

 

[tbone1004]

without telling us what your actual SAC rate was we can't tell you if it's that yours is high, or theirs is abnormally low. Some people just use more air, and those people tend to be the ones that are more fit than others. Can also be kicking styles and a number of other factors. If you have really muscular legs and you're using your thighs/butt to move around, you will use much more air than someone with less muscle mass who is doing a modified breast stroke kick/frog kick. They have smaller muscles and are using a small muscle group so they require less O2.

If you're a runner, your lungs are optimized for rapid O2 transfer, if you're a flute player, they aren't. Flute players trying to run will typically pass out, and a runner trying to play flute or tuba will typically pass out because their lungs have adapted to different usages. Doesn't mean that the musician isn't in shape, but it's two polar opposite uses of the lungs. For diving you want to be more musician like, less athlete like for the best SAC rate. Musicians have to breathe like swimmers when we work out because that's the way our lungs have adapted. You want to focus on rhythmic breathing while diving for optimized SAC rate. You can do this while you're working out/running and it will start to translate to your diving.

Start tracking your SAC rate every dive you do, it says a lot about how you were feeling on the dive. You can get a baseline by laying down on the bottom of a pool for half an hour and just hanging out. That is your absolute lower limit. 1.5x that is good for "normal". You can also get your "normal" by leisurely going back and forth or in circles around the dive well of a pool. Track against that.

Normal recreational diver : .65-.8cfm
Average SAC rate of experience diver .5-.6cfm
Good SAC rate <.5cfm

 

[Capt. Scott]

From what I've heard people with faster metabolisms tend to use more air than people with a slower metabolism. People with fast metabolisms tend to look fitter than people with a slow metabolism

 

[Roman_66]

Normal recreational diver : .65-.8cfm
Average SAC rate of experience diver .5-.6cfm
Good SAC rate <.5cfm

Do you have formula to translate it to liters per minutes ?
My SAC in warm water, known environment 16-18 liters per minutes, in more cold water and new environment,which I am not aware : 20-23

From what I've heard people with faster metabolisms tend to use more air than people with a slower metabolism. People with fast metabolisms tend to look fitter than people with a slow metabolism

Main reason that I fat, doctor said - slow metabolism, but looks I still use a lot of air....

 

[tbone1004]

1cf=28.3l

Normal rec=18-23lpm
experienced=14-17lpm
good= <14lpm

 

[Storker]

Normal rec=18-23lpm
experienced=14-17lpm
good= <14lpm

Add to this that your exposure protection may very well influence your gas consumption. At least it does for me. Since I use an AI computer, I'm getting data for every one of my dives, and typical numbers for me is:

Wetsuit (5-6mm thickness): 14-15 lpm
Summer drysuit (tight-fitting neoprene with just a couple of thin layers of wool underneath): 15-17 lpm
Winter drysuit (trilam with thick undergarments): 16-20 lpm.

All with the same type of tank and similar gear config, so the numbers are comparable.


--
Sent from my Android phone
Typos are a feature, not a bug

 

[tbone1004]

Storker,
you shouldn't see any significant change in your air consumption based on exposure protection provided your dives are the same. You might see a bit of a tick going from wetsuit to drysuit due to the extra air bubble, but you shouldn't see your winter drysuit going up by almost 1.5x air consumption unless you're doing a lot of sawtooth profiles. Lots of people quote water temp as being a factor in SAC rate, but it is purely mental and increasing your respiration rate only makes you get colder faster....