How does fitness level effect ongasing and offgasing at depth?

[CompuDude]

Originally Posted by namabiru

You know, I've often found the same thing. People who are dismissed as "fat" are frequently in decent physical condition. It's almost like there should be two standards-- genetically-large people, and 'regular' people.

With regard to scuba fitness, it's not actually an issue of "fat" (or simply heavy) vs "skinny"... it's not even a question of raw strength vs. just in enough (obviously it's an issue if you're so weak you can't lift your own gear).

It's a question of cardio-vascular conditioning and the effect that has on the overall cardio-pulmonary system. That's the main ingredient that needs working out, with respect to off-gassing.

In fact, the heavier people have the advantage of retaining heat better because of that layer of fat... and ironically, retaining heat helps prevent vascular constriction due to the cold, and thereby helps off gassing!

OTOH, the more muscular people need less lead to sink them, because muscle is a lot less buoyant than fat, so there's a trade-off...

But it's 100% certain that good cardio is better than a slim waistline when it comes to scuba.

[Buoyant1]

Originally Posted by CompuDude

With regard to scuba fitness, it's not actually an issue of "fat" (or simply heavy) vs "skinny"... it's not even a question of raw strength vs. just in enough (obviously it's an issue if you're so weak you can't lift your own gear).

It's a question of cardio-vascular conditioning and the effect that has on the overall cardio-pulmonary system. That's the main ingredient that needs working out, with respect to off-gassing.

In fact, the heavier people have the advantage of retaining heat better because of that layer of fat... and ironically, retaining heat helps prevent vascular constriction due to the cold, and thereby helps off gassing!

OTOH, the more muscular people need less lead to sink them, because muscle is a lot less buoyant than fat, so there's a trade-off...

But it's 100% certain that good cardio is better than a slim waistline when it comes to scuba.

Yeah...the "whale blubber" does come in handy for the crazy cold quarry diving I do! Case in point, my buddy who usually uses a dry suit had to use his 7mm since he sprung a leak. We got down to the second thermocline at about 60 feet, and he got "cold feet"! SO we ended up not going any deeper, and decided a "wall dive" was more comfy...

I also was a bit warmer in Key Largo in January 2006 than the local guy I dove with (who was wearing a full 3mm and a shorty 3mm over top, hood and ...nope...just checked the picture..no gloves..The other guy that was with us was getting cold, and his girlfriend bagged the second dive because she was freezing! (I just checked my log, and the minimum temp was 74!) I was more than comfy in my 3mm.

But...I do agree, this IS one of the sports that it doesn't matter your size, weight etc. just your overall physical fitness. (this also keeps me going to gym regularly!)

[cgvmer]

Sounds like me, overweight but working up to a mile of swimming 3 days a week, now to get that mile under 25 minutes.

[highdesert]

I'm not in the health care business, but my wife is, in particular relating to people's weight. True, you can be "overweight" or "obese" and be in relatively good shape. Bear in mind, though, that in comparison to another individual with the same muscle mass and fitness level as you, if they are leaner, they have a much better chance of a long life without a cardiac incident. I'm 6'3" and on my way down from 230, now at 215, heading for 200.

I know a guy my height and age who tips 250, and in pretty good shape. They had to jump start him 3 times in the ER, or he was a goner. Fit or not, the weight can kill you.

[Mtrewyn]

Originally Posted by highdesert

I'm not in the health care business, but my wife is, in particular relating to people's weight. True, you can be "overweight" or "obese" and be in relatively good shape. Bear in mind, though, that in comparison to another individual with the same muscle mass and fitness level as you, if they are leaner, they have a much better chance of a long life without a cardiac incident. I'm 6'3" and on my way down from 230, now at 215, heading for 200.

I know a guy my height and age who tips 250, and in pretty good shape. They had to jump start him 3 times in the ER, or he was a goner. Fit or not, the weight can kill you.

I think it is how hard your hart has to work, if you are big well the pump has to work harder to move all that blood around, not to mention that you have more blood to move, less weight is always better, but just like every thing else you can have too much of a good thing, you have to find that balance that works for you, if you are like me you don't fit neatly into "their" molds, so they are going to try and fit you into them so they can work easer with you, lots of different inputs from lots of different doctors, trainers and health pros is the way to go, question, question, question.

[divechaplain-sara]

Originally Posted by Mtrewyn

I think it is how hard your hart has to work, if you are big well the pump has to work harder to move all that blood around, not to mention that you have more blood to move, less weight is always better, but just like every thing else you can have too much of a good thing, you have to find that balance that works for you, if you are like me you don't fit neatly into "their" molds, so they are going to try and fit you into them so they can work easer with you, lots of different inputs from lots of different doctors, trainers and health pros is the way to go, question, question, question.

There you go making broad statements. Less isn't always better. For the majority of people (all except the extremely short) being overwieght at 200 lbs is much healthier than being underweight at 75.

[Chocoholic]

Yeah, it really is all about fitness. just watched a show RE: fat and where it is located, such as skinny people who don't work out (just diet) and have fat around their internal organs. Then there are large heavier people that work out and have very little fat around their organs, most people would think that the skinny one is in better shape, but not so.

[Mtrewyn]

Originally Posted by divechaplain-sara

There you go making broad statements. Less isn't always better. For the majority of people (all except the extremely short) being overwieght at 200 lbs is much healthier than being underweight at 75.

I thought that is what I said?

[hydro]

Another thing to mention regarding fitness level and BF% with respect to diving is the differing rates of on/offgassing for various types of tissues.

Fat is readily N2 soluble, but doesn't like to give it up so easily. Fat is one of the (if not, the) slowest diffusing tissues in your body. Bubble models usually account for a "compartment" that has an algorithm to include a certain percentage of BF, considered nominal.

While it's safe to assume this isn't an obscenely risky factor due to the low injury/fatality rate (likely from the tables having built-in padding for we less-than health fanatic Americans), anytime you dive to the limits with a higher BF % than what the table has allowed for, you're effectively bending that profile.

[divechaplain-sara]

Originally Posted by Mtrewyn

I thought that is what I said?

You said "less weight is always better." On re-reading your response I can take your too much of a good thing to be a negation of that--it just didn't stand out clearly to me that that was what you meant. I work in a hospital and I've seen anorexic people--overweight and even moderately obese people are usually much healthier.