Air consumption

[KeithG]

Is the OP a schwimmer?

I have no idea of my SAC thingy, but as a photog I am clearly a non swimmer. I (try to) splash first and then often get to observe the dive cluster flapping about over there until they disappear from view. I claim they swim at least 100% more distance than I do. Likely more.

My divebuddy and I once took on a third buddy on a liveaboard - the father of a father/daughter pair. We cautioned that we liked critters and would not swim much. Or none. After a great dive, we escorted him back to the boat ladder mid-dive and it ended as his longest dive of the trip.

Afterwards on deck he accosted us and demanded to know har far he had swam. We estimated 60 feet down, about 20 feet over.

 

[ozzydamo]

We are no doubt getting too far off subject, but might as well. I am sorry if you do not think the BMI is useful, I do, it is a statistical population tool useful for the vast majority of people to use for comparative purposes to gauge their weight. Again, professional athletes and body builders are not going to fit well in the chart because they are outliers. And, while we are at it, since we are way off subject. What if marathon runners got a five minute break every two miles and a 30 minutes halftime where nearly butt naked women shook their tuukuses and yelled, go Bill/Bob/Mary, go. I contend that many football players are not fit, they are fit for football, fit for lifting or whatever their entertainment specialty is but not fit for life. If the OP wants to get a lower SAC then one of the things he can do is to reduce his weight. You guys are grown ups, it is your hearts pumping through all that mass. Less of you means less of you needs to be fed O2, a heart that does not have to work as hard to pump blood and oxygen is healthier and the body will be more efficient as a result.

And you too should read what I said. Do not bother digging up some more pictures of muscle guys or pro football players. There are probably only ten pro football players who jump in a pool and swim five miles or run a marathon, they are always the exceptional and muti-talented. It is an odd thing that people have come to think distorted bodies are normal with women wishing to be boney thin but few can or should be and men wanting to bulk up but few bulk up with anything but fat so should not. Pro weight lifters and body builders and pro football players are not what a healthy person with good aerobic and general fitness look like, they are distortions for a specific purpose and in some cases a little bizarre. Here you go, note the part where he lost 100 pounds!

Former 300-Pound NFL Lineman Runs 3:56 Marathon | Runner's World & Running Times


I can google up stuff too. So, I will stay where I was, loose some weight, discuss it with a doctor or trainer what a proper weight for your specific body/person would be, concentrate on aerobic fitness with a target heart rate x some interval of time and develop a clear fitness goal and finally do some strength training and the SAC rate will come down.

Weird thing, I started do more weight/strength training, cannot seem to lose my winter fat and am stubbornly clinging to 175 pounds (okay, maybe even a few more than that ) and I want to be back at 165. Yet, I swam my fastest mile the other day and rode my fastest 25 mile bike since I broke my leg 4.5 years ago. I could just tell myself it is muscle and maybe some of it is but then I notice I have a little belly there too, so, no PBJ sandwiches for me for a while. Weight is not everything nor should it be, there is a balance in everything. Come to think of it, I think I will have a PB sandwich right now!

N

this is fit-
Ashtanga Yoga Shala - Teachers

 

[RJP]

Is the OP a schwimmer?

I have no idea of my SAC thingy, but as a photog I am clearly a non swimmer. I (try to) splash first and then often get to observe the dive cluster flapping about over there until they disappear from view. I claim they swim at least 100% more distance than I do. Likely more.

My divebuddy and I once took on a third buddy on a liveaboard - the father of a father/daughter pair. We cautioned that we liked critters and would not swim much. Or none. After a great dive, we escorted him back to the boat ladder mid-dive and it ended as his longest dive of the trip.

Afterwards on deck he accosted us and demanded to know har far he had swam. We estimated 60 feet down, about 20 feet over.

An appropriate goal for most divers would be to cover half the distance in twice the time.

 

[ajduplessis]

Slow down to a stands still....

 

[lv2dive]

If I read correctly, the OP is basing his SAC on his volunteer dives at an aquarium.... While there may be some ability to slow down, he does have activities to do that will necessitate using some amount of air (in this case).

 

[danvolker]

It is a known issue that the BMI alone is not the whole story and that it does not work with certain types of athletes. But the fact also remains that their hearts have to pump through all of that mass. The OP is not a pro ball player who makes his money abusing his body (and probably taking HGH). If you look at a lot of the pro players, they are carrying some jelly around their belly. Check with them again in an another twenty years and see how they are doing.

Do not fool yourself into thinking the BMI is not a useful tool just because pro ball players do not fit into the charts, technically, they are obese and if you did a body fat percentage I bet many of them would show it. I think a healthy number is under 17% for a fit adult male.

N

Really, BMI is a tool that has value pretty much only for the sedentary....If you see it being used by a doctor or health professional for an athlete, I will show you an "expert" that needs to go back to school!

With BMI, a pro bodybuilder weighing 300 pounds at 5 foot 10, is clearly obese, even though their water immersion body fat test shows them at 5% body fat..... More relevant, take a Velodrome Match Sprint and Kilo racer---a type of Cycling athlete that trains their anaerobic system, their aerobic system, and their ATP system, to an extreme level, and that often has legs as muscular as A BODY BUILDER, and an upper body as developed as an Olympic Pole Vaulter---they will have very low body fat, a VO2 max off the chart compared to the public, and they will be "obese", based on the nonsense of BMI.

---------- Post added March 23rd, 2015 at 09:00 AM ----------

For an athletic and muscular diver, there are 2 competing issues to deal with ( aside from all the issues of gear drag, trim, fin choice, and their coordination in fin swimming/propulsion and choice of kick and kick shape)....While the muscular diver could propel themselves with a lower percentage of maximal exertion--which can mean a lower heart rate and breathing rate....Just like a muscular cyclist, is becomes very important NOT to be contracting to many of the non-essential muscles. The cyclist engaged in a race speed paceline, or even a time trial--and the diver, need to quiet the neuromuscular connections to all the upper body and non-propulsive muscles.....large muscles can burn a great deal of O2, and manufacture a huge amount of CO2....and you don't want this....Cyclists learn to practically make their arms and chest go to sleep...almost become numb...in their attempts to shunt blood supply and contractions away from the muscles they don't want to be engaging.
New divers will often be so excited, every muscle in their body is "singing" with adrenaline, and all of their muscles are hyper-active, even though most of these muscles have little purpose for the diver's trek through the water....and the constant stimulation of each of these muscles is going to add drastically to the CO2 production already discussed in this thread.
When you hear that a diver tries to "Zen out" at the beginning of a dive, to quiet all the non-essential muscles---this does work to shut down alot of the errant contractions, and to eliminate the use-less workload and large CO2 results.

Some of the most muscular divers I have seen, get terrible SAC rates due to so many muscles being allowed to be engaged through out the dives---others, that learn to "shut down all non-essential systems" , can easily get to below .3 SAC rates when not stressed.

 

[Kharon]

And the Award for Most Reasoned / Most Patient goes to Imla with Richard as runner up.

The award for Snarkiest Point Misser goes to RJP.

My congratulations to the winners and condolences to the losers.

 

[danvolker]

Final thought for this subject.... Think of the fins as levers, that help our mechanical advantage in pushing water into a specific direction, in order to gain the movement or forward speed we desire. Bigger fins are bigger levers.....some carbon fiber composite fins are more effective levers for this than low tech rubber fins, but there is still the issue -- where given a larger lever with the same engineering, more force will be required for the legs to describe the arc they use to develop thrust---we get a "bigger gear"....

Eliminate all the drag from from a vehicle like a 580 horsepower truck that gets 6 mpg at 60 mph....(get rid of floppy jacket BC and tons of danglies, AS WELL poor trim, etc) -- Look at a higher form of function Like a Lamborghini Gallardo that with very low drag, and 580 horsepower, we see this power ( the big muscles in a diver or cyclist) able to get the Gallardo to 90 mph with about 30 mpg, as long as this speed is sustained and constant. Obviously sprints of big muscles or big engines, drops your mpg quickly. The biggest gear on the Gallardo, is a really big gear--- 90 has it barely above idle....The Veledrome cyclist, suddenly become diver, is the same thing, reincarnated as a diver...They can have an incredibly low mpg---I mean SAC rate, with a very big set of the right levers/fins ( Like DiveR Freediving blades), and this diver can have massive bottom time, as long as they stay at an idle....and their idle can have them moving at 2 or 3 or even four times the speed of the "big dumptruck divers" with all the drag( pufferfish bc, double tanks, drysuit, danglies, etc) and gearing for high drag, rather than gearing for efficient speed with almost no drag......
Without the very strong muscles, the diver can not push the really big levers--the really big gear....With weak muscles, the diver needs soft floppy split fins, so that the little muscles are not running at full power...So the weak diver, say with a 150 horsepower engine, looses the benefit of the engine that runs using less gas, because the little engine has to use a tiny little gear or it overloads the engine. (The soft split fins are the tiny little gear)....Get rid of all the high drag gear on this diver with the small engine, and he/she can use a bigger set of levers, to become far more efficient, and be able to cruise at higher speeds, with better mpg's ( SAC rate)...Taken to extremely low drag, this 150 HP diver can do extremely well, though maximum cruise speed should be better for the velodrome diver....BUT, add some sprints after a turtle, Goliath or shark or lobsters.....and the Lamborghini diver just went to 4 mpg with the big engine processing massive amounts of O2 and Co2....while the 150 HP diver still has quite a bit of air left---full speed for them is still only with 150 hp engine, and it just does not burn that much gas, that fast

 

[RDRINK25]

And people thought that a discussion of BMI would take this thread off track?

Remember Aquarium dive... Required to take Spare Air with us not that I have ever seen anyone use one.

 

[RJP]

Remember Aquarium dive... Required to take Spare Air with us not that I have ever seen anyone use one.

Is that so you can run out of air TWICE on the same dive?