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>Just because you're big doesn't make you a bad diver. I'm 5' 8" and weigh >215# and can probably outswim most of you skinny guys. You can't tell me >that it is all that important what your body fat content is, as long as you >can do the work and you don't breathe too much air. It should be obvious >that the marine mammals that are best adapted to the aquatic environment >are the ones who have high concentrations of body fat, like whales and sea >lions. > >George C. George, First, please don't take this whole fitness thing as a personal attack---yes, sometimes the conversations degrade into this, but the ultimate reason for the fitness issue, is to make all cave and tech divers safer. Marine mammals like Elephant seals, shunt blood throughout their bodies during deep dives, essentially reducing the gradient exposure to most body tissues, and utilize many other physiological adaptations which we do not have. Sperm whales even take this physiological adaptation to the point of doing their own "rest interval" or deco stop, at about 30 feet deep after 1st surfacing and getting air for a minute or so after a deep dive, where they languish about for 15 minutes at a time, as opposed to finishing a deep dive and staying on the surface----this just illustrates there are many marine mammal adaptations you, or even the much larger Bret Gilliam, will never be able to simulate. So the idea that "fat" is OK in human deep diving, just because of some similarity to marine mammal body fat levels, is far too simplistic. You will NOT in-gas the same way marine mammals do, and you won't off-gas the way they do either. AND, even the thermal regulation that marine mammal fat provides them with, is drastically unlike the protection even the most obese of us is afforded by our own subcutaneous fat----we do NOT have the heat regulation circulatory architecture below an insulating layer of fat, in any way similar, to the way marine mammals do. Please disregard this notion of FAT being OK for us, because of marine mammals----this type of thinking will make obese people improperly justify their obesity in their own minds, and will hamper any logic that may otherwise compel them toward fitness. We actually see this type of thinking rampant at huge dive industry events like the annual DEMA show. Last year's DEMA event in Orlando was a particularly good example of this---it took place right next to the Surf Show, which is also huge, and the average body type seen at DEMA, must have been a good 25 to 45% bodyfat, whereas next door at the surf show, the average bodyfat levels ran closer to 12% to 23%. Clearly a powerful indication of what is "acceptable" in each of these two populations, and in diving, driven by beliefs like the marine mammal myth. Regards, Dan Volker / -- Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
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