View Full Version : Air consumption VS. Muscle Mass (Leeching cells)

08-29-2007, 20:08
I'm kinda thinking if you have too much muscle, (more then you need to safely accomplish your underwater mission) as you move all that extra muscle would probably be using up your o2 for nothing more then waste. So there has to be an optimum weight or BMI (Body Mass Index) for scuba divers. If body builder and endurance athlete in the same cardiac shape were to sit on the bottom of a lake @ 50ft the body builder would probably use up his air faster then a leaner endurance athlete underwater just because off of the extra cells needing o2 let alone factoring in his movement. So does it really pay to work out or just stay out of shape so you don't carry around more leeching cells?

09-13-2007, 18:21
I don't have a 'proper' answer for you, but here goes some opinon. A bigger person {take it from me!!!} will almost always use more air as they have more to move. Next take a look at body types of the same size, I will almost always give better air consumption to the person in shape, as their lungs, circulatory system, muscles are more accustomed to moving oxygen through the body.

Side note, can we please stop using the BMI (Body Mass Index) as a bench mark! It is a left over from the 60's/70's insurance buisness that still pops it ugly little head up. BMI only takes two factors into account ~height and weight. Not a very accurate tool to identify body types. A better method is to look into your body composition and identify percent of fat and lean body mass.

Hope this helps a little.

09-13-2007, 20:21
yep I had a friend who was technically obese by bmi but he was the same height as me and had 50 lbs of muscle on me.

09-14-2007, 07:38
BMI is worthless, the last time I had one by BMI I have a 28% fat content. Done by a submerssion test, I was at 13%.

As for air consumption- the more fit diver will also work less to more themselves. But when it comes down to it, I would generally say that fitness and comfort are the 2 critical factors to reduce consumption, but really think that it has more to do with comfort than anything else.

09-14-2007, 10:13
The more muscle you have the more oxygen you require because muscle tissue uses oxygen for two of it's energy production pathways. Since fat is merely an energy store, and not helping to propel the body, so it's oxygen demands are less. It's the same with metabolism: you can take two people, one with a high ratio of lean body tissue and one with a low and have them do the same activity, but the person with more muscle will burn more calories just by having more muscle tissue to support and maintain.

However, as some people correctly pointed out, most people who have developed good musculature have simultaneously developed good cardiovascular fitness, which means they do not get, in the scientific term, as 'winded' as other people doing the same activity, because their lungs and heart have become very efficient.

(Side note, a small minority of body builders have really crappy cardiovascular fitness, but the majority of divers are not competitive body builders so it really doesn't apply)

The BMI calculated on height-weight alone is rather silly and really general, but calculated on real body composition is great. The 9-point caliper test is cheaper than the submersion test, though not as accurate. I personally am a fan of body composition instead of weight alone as one measure of fitness. Heck, you can even do a 1-point test at home by 'pinching an inch.'

But all that aside, nothing can replace good cardiovascular fitness and good buoyancy control for regulating air consumption.

09-14-2007, 16:57
im gonna agree on the Body mass index point... its pointless.
im muscles, and have something like 17% and my neighbor, not muscles... but a very tall big boned person, large frame... is only 22%.... cant be right!

09-14-2007, 22:23
Two years ago when I was running 2 miles a day.....I sucked air big time....now that I do not run and put on 20lbs....I still suck air but not as bad....go figure!....kinda sad on my part!

09-20-2007, 13:48
I think it's more about how often you dive and how well you are at controlling buoyancy than anything else.

Sure the rest of it matters but you get my drift......

09-20-2007, 14:24
I will second and sayits a matter of how often you dive. I myself can see aslight difference on vacation when I dive my first vs. my last dive. I would think that doing cardio traning not weight training would also help

09-20-2007, 20:58
I'm not sure if this is a muscle mass thing or not but I have noticed that as I have gotten into better shape I seem to be using more air. I've dropped a little over 30 pounds and have been doing a mix of upper body and cardio workouts. My guess is that when I exert energy, my muscles now require more "fuel" which consume more air and burns more calories. That's just a wild theory though.

09-20-2007, 22:17
I just went out and got a mile of running in....trying to lose that 20lbs before Wakatobi.....hell it sounds like I need a cookie and milk!

09-23-2007, 20:55
I suppose the BMI is one of those general measures that applies to most people. But for people who are not in the mainstream it doesn't appear to be very useful since, as has been posted, it doesn't take into account body type, composition, or, for that matter, lung size.

So, the very fit heavy weights, like weight lifters, and light weights, like runners aren't scored very accurately.

Personally, I like the combination of measured physical ability and body fat percentage.

10-05-2007, 08:51
So does it really pay to work out or just stay out of shape so you don't carry around more leeching cells?

"Working out" doesn't mean you have to build mass. You can increase your stregth and be a lean, mean, diving machine.

WV Diver
10-05-2007, 09:09
I do not know of any scuba related studies that have been done in regards to the BMI.

Building muscle and droping fat is a better alternative than "staying out of shape" as you say. Will alot of extra muscle use more air compared to alot of extra fat?.............I don't know.

What I do know is that there is more to be concerned about here than how much extra air you might or might not use, over the course of one tank, if you lean toward one side or the other.

A good diver needs to have good cardiovascular health in order to better facilitate his own and his buddies enjoyment and safety of the sport of scuba diving. It is much more important to have this than it is to be able to lift the boat.

Don't fool yourself into thinking that being out of shape is beneficial to you.

10-05-2007, 09:41
The optimal body type for a diver would probably be similar to a marathon runner; very lean, not much muscle. I simply base this on the fact that small women tend use less gas than large men (all else equal), and because you don't need much muscle to dive so it's just using up energy and creating drag, and fat too creates drag hence the marathon runner body type is likely to be optimal for diving - especially for long technical cave dives and such.

That said, who here would seriously sacrifice their hard earned muscle mass for a slightly better air consumption rate? Besides, most of it probably depends on breathing technique anyway.

10-06-2007, 00:28
I think I read some where that N2 disolves faster in fat then lean tissue? not that realy does any thing for your question, but it would be a good arguement for being lean.

I agree with the BMI being crappy, I have a 30-33 BMI, but only around 15%-17% fat.

I love it it makes the so called "experts" Dietations, and Doctors that I work with around the Hospital nuts, and I just smile and say, "I guess you just don't know it all"