Ama physiology

[Primum Sapienti]

From 1967

Quite a number of interesting facts.

http://userhome.brooklyn.cuny.edu/anthro/jbeatty/CORESEA/AMA.pdf

The Diving Women of Korea and Japan

Some 30,000 of these breath-holding divers,
called ama, are employed in daily foraging
for food on the bottom of the sea.

Their performance is of particular interest
to the physiologist

"She carries a counterweight (of about 30 pounds)
to pull her to the bottom..."

"If she dives deeper than the level of maximum
lung compression (her "residual lung volume"),
she becomes subject to a painful lung squeeze;
moreover, because the hydrostatic pressure in
her blood vessels then exceeds the air
pressure in her lungs, the pulmonary
blood vessels may burst. "

"Lanphier has calculated that repeated dives to
depths of 120 feet, such as are performed by male
pearl divers in the Tuamotu Archipelago of the
South Pacific, can result in enough accumulation
of nitrogen in the blood to cause the bends
on ascent."

"To compensate for this loss the Korean diving
woman eats considerably more than her nondiving
sisters. The ama's daily food consumption amounts
to about 3,000 kilocalories, whereas the
average for nondiving Korean women of
comparable age is on the order of 2,000
kilocalories per day."

"They showed, for one thing, that with the same
thickness of subcutaneous fat, divers had less
heat loss than nondivers. This was taken to
indicate that the divers' fatty insulation is
supplemented by some kind of vascular adaptation
that restricts the loss of heat from the blood
vessels to the skin, pmticularly in the arms and
legs. Secondly, the observations disclosed that
in winter the diving women lose about half of
their subcutaneous fat (although nondivers do
not)."

[Mario Petrinovic]

Of course, you misunderstood everything. They don't dive in winter, I
suppose. Their SC fat works better because they have the adaptation.
When you have adaptation to some environment, this is the proof that you
are adapted for that environment. If you wouldn't be adapted, you
wouldn't have the adaptation. I know that this is so hard for you to
understand, so, don't even try, just believe whatever you've been told,
you will not be able to understand anything with your own mind, anyway.

[Primum Sapienti]

Yes, they DO dive in winter. It even says so in the
paragraph right above:

[Mario Petrinovic]

No, this doesn't mean that they dive in winter. The guy separates
"diving women" and "non diving women". Diving women dive, and do this
for living, but it isn't said whether they dive whole year, or only when
waters are warmer. One would presume that they don't dive when waters
are too cold. "Non diving women" on the other side, can dive
recreationally, but they are not doing it as a job.
Ok, I took a look at Wikipedia.
First, it is women who are doing diving (as opposed to men), because
they have better fat distribution than men. So, fat has the major role
here. It is known that men have muscle tissue, while women have fat.
Second, it is said that there is a diving season. So, they are not
diving whole year long. One would presume that the season is in
favorable conditions, not in winter.
Third, in Wikipedia they say that those women actually lose weight
during diving season. Which could be because of physical strain, since
they probably don't work as hard out of the season.

[Mario Petrinovic]

OK, I found out, diving season is strictly from March to 14th of
September. They don't dive in winter.

[Primum Sapienti]

Follow the link.

"By and large the divers wear minimal clothing,
often only a loincloth, during their work in
the water. Even in winter the Korean divers wear
only cotton bathing suits. In Japan some ama
have recently adopted foam-rubber suits, but most
of the diving women cannot afford this luxury."

"Even in winter"

"In the last analysis the amount of time one can
spend in the water, even without holding one's
breath, is limited by the loss of body heat. For
the working ama this is a critical factor,
affecting the length of their working day both in
summer and in winter."

"in winter"

"In both seasons at the end of a single diving
shift (40 minutes in the summer, 25 minutes in
winter) the deep-body temperature was found to be
reduced from the normal 98.6 degrees F. to 95
degrees or less."

"in both seasons" "in winter"

etc

>         Ok, I took a look at Wikipedia.

This wiki article (just to be clear)

https://en.wikipedia.org/wiki/Ama_(diving)

>         First, it is women who are doing diving (as opposed to men),
> because they have better fat distribution than men. So, fat has the major
> role here. It is known that men have muscle tissue, while women have fat.

aa says they should really fat.

>         Second, it is said that there is a diving season. So, they are not
> diving whole year long. One would presume that the season is in favorable
> conditions, not in winter.

Yes, they are. That wiki page says

"The ama were expected to endure harsh
conditions while diving, such as freezing
temperatures and great pressures from the
depths of the sea."

"freezing"

>         Third, in Wikipedia they say that those women actually lose weight
> during diving season. Which could be because of physical strain, since they
> probably don't work as hard out of the season.

Which is what I said. aa says the fat is supposed to
keep them warm. It doesn't if that activity means they
lose it.

[Mario Petrinovic]

Ah, I didn't bother with your link, since I saw it is from 1967., but
it looks like it is pretty detailed. Well, my info is recent, and I
believe it is about Korean ama. Anyway, I will not bother about it
still, it is pretty clear that SC fat is for aquatic purposes. I mean,
as far as I can tell, all those amas are women. Which doesn't explain
everything (since ama diving wasn't economical, men would do something
that is economical), but explains enough. You don't know much about SC
fat, go and read something, it is absolutely clear that it is for
aquatic lifestyle. And it isn't you that I am worried about, this should
be absolutely clear to scientific community, yet it isn't, and this is
what makes people like you to behave like you behave.

[Primum Sapienti]

Which means that they have modified their
practice. From the wiki link

"The number of ama continue to dwindle as this
ancient technique becomes less and less practiced,
due to disinterest in the new generation of women
and the dwindling demand for their activity. In
the 1940s, 6,000 ama were reported active along
the coasts of Japan, while today ama practice at
numbers more along the scale of 60 or 70 divers
in a generation."

To say that the practice is dying out would be fairly accurate.

[Marc Verhaegen]

Op maandag 5 februari 2024 om 22:36:04 UTC+1 schreef somebody:

> From 1967
> Quite a number of interesting facts.
> http://userhome.brooklyn.cuny.edu/anthro/jbeatty/CORESEA/AMA.pdf
> The Diving Women of Korea and Japan
> Some 30,000 of these breath-holding divers,
> called ama, are employed in daily foraging
> for food on the bottom of the sea.

Yes, voluntary breath-holding is exclusively seen in (semi)aquatic mammals.

> Their performance is of particular interest to the physiologist
> "She carries a counterweight (of about 30 pounds)
> to pull her to the bottom..."

Yes, that's why H.erectus had pachyosteosclerosis (google):
very thick & heavy skeleton (probably more brittle: too much calcium), exclusively seen in tetrapods that regularly dive for littoral foods
= diving-adaptation in slow+shallow-diving, e.g. Sirenia, earliest fossil Cetacea etc.
(Not vice versa: deep+fast divers such as present-day Cetacea have light skeletons!)

> "If she dives deeper than the level of maximum
> lung compression (her "residual lung volume"),
> she becomes subject to a painful lung squeeze;
> moreover, because the hydrostatic pressure in
> her blood vessels then exceeds the air
> pressure in her lungs, the pulmonary
> blood vessels may burst."
> "Lanphier has calculated that repeated dives to
> depths of 120 feet, such as are performed by male
> pearl divers in the Tuamotu Archipelago of the
> South Pacific, can result in enough accumulation
> of nitrogen in the blood to cause the bends
> on ascent."
> "To compensate for this loss the Korean diving
> woman eats considerably more than her nondiving
> sisters. The ama's daily food consumption amounts

> to about 3000 kcal, whereas the
> average for non-diving Korean women of
> comparable age is on the order of 2000 kcal/day."

> "They showed, for one thing, that with the same
> thickness of subcutaneous fat, divers had less

> heat loss than non-divers. This was taken to

> indicate that the divers' fatty insulation is
> supplemented by some kind of vascular adaptation
> that restricts the loss of heat from the blood

> vessels to the skin, particularly in the arms and

> legs. Secondly, the observations disclosed that
> in winter the diving women lose about half of

> their subcutaneous fat (although non-divers do
> not)."

Yes, thanks a lot, this nicely confirms we had frequently-diving ancestors still in the Pleistocene:

Ape+human evolution, recent insights, google e.g.
- David Attenborough Marc Verhaegen
- Gondwanatalks Verhaegen
- aquarboreal
- Mario Vaneechoutte cs 2024 Nature Anthropology 2,10007
“Have we been barking up the wrong ancestral tree?
Australopithecines are probably not our ancestors”
open access https://www.sciepublish.com/article/pii/94

[Primum Sapienti]

Marc Verhaegen wrote:
> Op maandag 5 februari 2024 om 22:36:04 UTC+1 schreef somebody:
>

>> From 1967
>> Quite a number of interesting facts.
>> http://userhome.brooklyn.cuny.edu/anthro/jbeatty/CORESEA/AMA.pdf
>> The Diving Women of Korea and Japan
>> Some 30,000 of these breath-holding divers,
>> called ama, are employed in daily foraging
>> for food on the bottom of the sea.
>

> Yes, voluntary breath-holding is exclusively seen in (semi)aquatic
mammals.

You mean like those diving puppies? Crab eating macaques? ;)

>> Their performance is of particular interest to the physiologist
>> "She carries a counterweight (of about 30 pounds)
>> to pull her to the bottom..."
>

> Yes, that's why H.erectus had pachyosteosclerosis (google):
> very thick & heavy skeleton (probably more brittle: too much
calcium), exclusively seen in tetrapods that regularly dive for littoral
foods
> = diving-adaptation in slow+shallow-diving, e.g. Sirenia, earliest
fossil Cetacea etc.
> (Not vice versa: deep+fast divers such as present-day Cetacea have
light skeletons!)

Ama look nothing like that.

>> "If she dives deeper than the level of maximum
>> lung compression (her "residual lung volume"),
>> she becomes subject to a painful lung squeeze;
>> moreover, because the hydrostatic pressure in
>> her blood vessels then exceeds the air
>> pressure in her lungs, the pulmonary
>> blood vessels may burst."
>> "Lanphier has calculated that repeated dives to
>> depths of 120 feet, such as are performed by male
>> pearl divers in the Tuamotu Archipelago of the
>> South Pacific, can result in enough accumulation
>> of nitrogen in the blood to cause the bends
>> on ascent."
>> "To compensate for this loss the Korean diving
>> woman eats considerably more than her nondiving
>> sisters. The ama's daily food consumption amounts

>> to about 3000 kcal, whereas the

>> average for non-diving Korean women of
>> comparable age is on the order of 2000 kcal/day."

>> "They showed, for one thing, that with the same
>> thickness of subcutaneous fat, divers had less

>> heat loss than non-divers. This was taken to

>> indicate that the divers' fatty insulation is
>> supplemented by some kind of vascular adaptation
>> that restricts the loss of heat from the blood

>> vessels to the skin, particularly in the arms and

>> legs. Secondly, the observations disclosed that
>> in winter the diving women lose about half of

>> their subcutaneous fat (although non-divers do
>> not)."
>
> Yes, thanks a lot, this nicely confirms we had frequently-diving
ancestors still in the Pleistocene:

Long legged, sleek, trim, little fat ;)