Brick Carter wrote:
>
> A Discovery Channel documentary featuring the sperm whale explained that its
> deep diving ablility for long periods was due to the tremendous muscle mass
> acting as an oxygen store.
>
> Since humans share the "mammalian diving reflex", should this mean
> bodybuilders make better freedivers than marathon runners?
>

No, I don't think so. Or rather, they might be better divers but not
exactly for that reason. Or they might be worse divers. What makes
whales able to dive isn't just the mass of their muscles, but special
characteristics of the muscle tissue. Indeed, it's your muscles that are
using oxygen, so just having more muscles would mean using more oxygen,
which would seem to be a break-even at best. Harold McGee in "On Food
and Cooking" says that whale muscle is almost black with intense
concentrations of myoglobin (the form in which oxygen is stored inside
cells, like the hemoglobin in blood). Whales have large muscles that are
in nearly constant motion, and are the slowest of slow-twitch muscle.
Which means they have many mitochondria and burn fats using oxygen. But
beyond that they have adapted to the special requirements of diving by
storing extra huge amounts of oxygen right in the muscle. (If they took
giant lungfuls of air down there instead they would have all that
buoyancy to overcome). I would think that being strong and muscular
would make you a better diver, but the whale thing is a bit different.