Muscle mass and air consumption

In general, women seem to have lower air consumption than men. The explanation generally given for this is that men have more muscle mass, ergo a higher basal metabolic rate, ergo higher air consumption.

Well, in January, when diving in Grand Turk, I had an experience which challenges that explanation.

While we were diving there, they were shooting a made-for-PAX-TV movie. Some of the actors dove with us on days when they had a break. One of those actors was Ralf Muller. You might remember him from the movie, Gladiator. He was the really BIG German gladiator who took a bite of Maximus' (Russel Crowe) food and pretended to be poisoned.

Seeing him in the movie, you don't realize quite how big this guy is, because all the gladiators were fairly big. He was Mr. Universe in 1986. He is 7'3" tall and 275 pounds of mostly muscle.

I thought this guy was going to suck his tank dry in about 10 minutes. His basal metabolic rate must be enormous.

But he didn't. We usually had 5-6 people on the boat. I usually was the last to come up, and even when I did, it was just so as to not keep everyone waiting -- I usually came up with 800-900 PSI left in the tank. My husband swears I have gills. Ralf came up only 5-10 minutes before I did. Admittedly, he probably had less in his tank, but he was probably 4th or 5th out of the 6 divers to come up.

Now what is the explanation for this? Does fitness overrule muscle mass?

What are all the components that contribute to rate of air consumption? I can think of the following possibilities:

1. Muscle mass.

2. General cardiovascular fitness.

3. State of calmness or anxiety.

4. Level of exertion (are you doing a gentle drift dive, flipping along in a leisurely fashion, or trying to make headway against a current?)

5. Style of breathing (deep and slow being better than shallow and fast).


Comments? Opinions? Explanations of why Ralf's air consumption was so good? I'd like to hear them.

Air consumption is a puzzling fenomena
And generaly size is a factor,and some times
you do get small men AND women with
high sac rates.
AS a dive leader taking a varied diver base out to dive
one learns never to go by appearences.
I've had big guys with decent breathing rates
and experienced medium sized divers drop to 100 bar in under
5min.
I,m TALKING BESIDES THE general physics laws
here besides genral state of wellbeing.
sometimes i think there are some of us who can absorb
oxygen through our skin.
Howard

I will proffer the following hypotheses to explain Ralf's low air consumption:

1) high level of fitness that you all ready noted
2) economy of motion underwater
3) shallow dive profile (it sounded like you were diving randomly)
4) psychological fitness (could be that he is very calm and relaxed underwater which makes for a relaxed respiration rate)
5) maybe his tank was almost emptyeek:

Profile was that we all went to the wall and descended to around 85 feet, stayed there for about 20 minutes, then ascended to the shallows (30-50 feet) where we would stay for various lengths of times depending on air consumption.

My stats are 6', 225lbs (that's about 102kg to the metrics and 16stone 1 to the poms)... I've got a pretty decent benchpress, played rugby and ride my bike about 200miles a week during the summer.

When I was in Largo on my first deep dive ever, I hoovered a tank in a heartbeat. It was the first time I was deep, I was hungover, and I was nervous as poop.

Later that day, I was the first in & last out; the next day, I was first in & came out of the water with 1500+ left after an hour at 30some feet.

I reckon it's all about fit & mellow you are.

When we were teaching in Belize our head divemaster was a pretty good sized guy. Not all of it was muscle, he had a pretty healthy gut. He was also known to have more that one or two beers of an evening. This guy used no air!. My consumption is pretty good and my wife's (also an instructor) is really good, she's been accused of having gills. He would beat either of us every time. His consumption was half that of the typical guest.
Underwater he was completely relaxed. So - at least with him relaxation and economy of movement trumped extrodinary fitness

I am a 32 y.o. male, 5'9" and 225 pounds. I am not cardio fit and don't have a lot of muscle ( I know ladies - soooo attractive anyhow...

I always match my fit friends air consumption pound for pound when diving... I think the idea is to keep you basic breathing rate close to that of your base rate - while at rest everyone breaths at about the same rate right (I am guessing at this)? I bet that in those dives that require more physical exertion - like when fighting current - that the differences in air consumption would become more pronounced.

so I only offer the following ...I am 5' 10" and 285 good mis of muscle and fat (hehehehehe) I use very little air compared to a lot of my dive buddies. I believe it is a mix of genetics and cardiovascular training..I do a lot of weight lifting and cardio exercises...every day....

If the guy was Mr. Universe in the past, you are talking about a guy who has put in more time in the gym than most of us can comprehend. He's big and muscular and probably in outstanding cardiovascular shape.

Being efficient with you kicks and movements is important too. One of the biggest things is how comfortable the person is in the water. Maybe he's been diving for a while and is really relaxed. As you mentioned, a solid breathing pattern helps too.

What kind of a SAC rate qualifies you as a hoover and what SAC rate suggests that you have gills? For most of my diving career I haven't kept track of my SAC, but on a few dives over the last year and a half I've calculated SAC rates of between .59 and .70. Is that good? What is average?