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Swimming after lunch

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672398.  Thu Feb 18, 2010 7:45 am Reply with quote

soup wrote:
PDR wrote:
the amount of "digesting" that goes on in 30 minutes is pretty minimal.

Especially if the food is carrots which have a half life of 2.3 gagillion years in the gut.
Ever been sick five hours after you have eaten anything, there is still carrots in 'it'?

Arent' the carrots actually supposed to be stomach lining or something?

672463.  Thu Feb 18, 2010 10:31 am Reply with quote

I remember reading in an old Reader's Digest about some guy in (I think) Canada in the late 19thC/early 20thC who suffered some injury to his stomach which healed in such a way that there was a hole left via which doctors could investigate the digestive process in a living person. They discovered that excercise reduces the flow of digestive fluids. Thus it would seem that swimming/volleyball/Wii tennis/whatever is generally a bad idea.

It was also noted that human digestive fluid is the most pwerful natural solvent in the world, and given time it will digest bone!

All the above is from memory of reading the article a couple of decades ago. I'm fairly sure my dad still has the book on his shelf, I will try to check it out next time I'm round at the folks for sunday lunch.

672489.  Thu Feb 18, 2010 11:36 am Reply with quote

It's not a solvent - it's hydrochloric acid IIRC.


672560.  Thu Feb 18, 2010 3:21 pm Reply with quote

it's hydrochloric acid plus a couple of enzymes. and it's definitely not the strongest of its kind. some species have stomach juices strong enough to digest prey animals in their entirety.



Eric the Underwriter
672577.  Thu Feb 18, 2010 3:45 pm Reply with quote

Impact is the key factor here.
Belly flop can cause injury very easy. Basicly it's a big sucker punch to the stomach.
It is not swiming!

672946.  Fri Feb 19, 2010 12:29 pm Reply with quote

Hello Eric - we don't see you around often, but you always have a good point to make when you post :-)

677202.  Mon Mar 01, 2010 6:42 am Reply with quote

crissdee wrote:
I remember reading in an old Reader's Digest about some guy in (I think) Canada in the late 19thC/early 20thC who suffered some injury to his stomach ...etc....

Seems my memory of decades old reading was little off. The incident happened in 1822 in Michigan to a guy called Alexis St Martin. The doctor reported that:

"Gastric juice is the most general solvenbt of food in nature, even the hardest bone cannot withstand its action"

Also. it seems that it was hot, humid weather that was seen to suppress digestion, not excercise.

691724.  Fri Apr 02, 2010 2:08 pm Reply with quote

The debunking still stands. It's quite possible to choke on your food because of a bad dive, but the myth never said anything about diving.

692354.  Sun Apr 04, 2010 12:30 pm Reply with quote

The reason for not swimming, or indeed any other vigorous exercise soon after food that I was given in my teens was that digestion demands a lot of blood; the body diverts a lot of red stuff to help with peristalsis and taking away of the nutrients.
This leaves less blood available to take oxygen to muscles, or to go to the surface to help the body cool.
Hence the whole blood system can be put under stress, which is not conducive to having a good day.

I have just asked my Better Half, who was told that swimming after a meal would cause stomach cramps, and the sufferer might then go (as she mimed doubling up in pain) 'Ooh aah gurgle'

Cats and snakes, for example, have a good long nap after feeding, so maybe there is a good physiological reason for not indulging in exercise soon after nosh.

765576.  Tue Dec 07, 2010 2:56 pm Reply with quote

Came across this thread, and thought "Siesta". Mediterraneans also have the habit of having a nice snooze after their lunch. Well, at last they used to. Not sure whether that is still the case.

765812.  Wed Dec 08, 2010 3:57 pm Reply with quote

'yorz wrote:
Came across this thread, and thought "Siesta". Mediterraneans also have the habit of having a nice snooze after their lunch. Well, at last they used to. Not sure whether that is still the case.

Yes, but this is because in the hotter locations the middle of the day is the hottest time, so there is a culture of dividing the woking day into two parts before and after the hot part to avoid exertions in the hot period.

There *is* another reason for nor swimming after a heavy meal. The full stomache takes up more space, and when subjected to external pressure (eg when floating) it is pushed up into the diaphragm and restricts the available lung capacity. If your stomache is *very* full then breathing can be dangerously restricted causing the person to pass out (as for edwardian women in tight corsets) and potentially even drown.


770060.  Mon Dec 27, 2010 8:03 am Reply with quote

The whole "no exercise after eating" idea seems to come from the Victorians. They were really big on the concept of blood flow being shunted around the body (as mentioned above by Tetsabb). It followed logically that if you've just eaten, most of your blood would be diverted to your digestive system. If you then tried to exercise, your muscles would try to hog the blood supply. Either the stomach or the muscles would end up with insufficient blood, causing cramps.

I think the point about swimming in particular is the extra danger of drowning if you get cramps.

There is a natural tendency to become drowsy after a meal. A full stomach stimulates the parasympathetic nervous system, which gives a general "slow down" signal to the body. The parasympathetic system controls the at-rest state, including promoting digestion. So there is an advantage to keeping quiet and devoting the body's resources to food processing.

T J Alex
891230.  Sat Mar 03, 2012 5:16 pm Reply with quote

A mouthful of wate,r while swimming after a heavy lunch could well lead to vomiting, followed by choking, followed by drowning.

The first two bits actually happened to me, but luckily not the last.

891240.  Sat Mar 03, 2012 7:48 pm Reply with quote

Is it also possible that the act of CPR performed not quite correctly caused the patient to vomit by forcing the stomach contents up? IIRC, if you placed the hands too far down or pushed too hard, that could happen. Perhaps shock caused the patient to vomit?

In any case, drinking alcohol before swimming is likely far more dangerous and would account for more deaths.

891268.  Sun Mar 04, 2012 4:31 am Reply with quote

I tried swimming after lunch - but those fish are too darned fast...


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