if you really got that under your belt, you definitely know alot more then i do so i wont argue that. Im really confused y so many ppl are wasting there time with it. As a serious question what happens to it, does it get stored as fat? Do you digest it later? Im always up to learn something new
During large bouts of strenuous exercise, blood flow to the digestive system is largely shut off. This includes the kidneys, intestines, stomach, and a few other smaller organs such as the pancreas.... kind of. This is where it gets complicated, the capilaries near the surface of your skin dialate to allow more blood to flow closer to the surface allowing for better heat exchange. The blood that once went to the GI tract is now mostly rerouted to the limbs and heart which masically means that extra blood is where your pump comes from.
Some organs like the kidneys almost completely shut down, which explains why long distance runners aren't seen peeing on the side of the road every 2 miles.
Once exercise is stopped the capillaries near your skins surface begin to constrict and blood returns to your digestive system. There's quite a bit more detail to the picture but that's the general big picture for you. This is why if you eat a big meal and then run for a long time you are probably going to get sick, because the food isn't really going anywhere.
After everything returns to normal your body pretty much starts where it left off, but now it has to repair damage done to it as well. Food will be converted to glucose and broken up in to amino acids which are then reformed in to whatever large amount of proteins your body needs in the liver before being shipped off to cells for selective use. Excess glucose gets stored in fat cells as well as protein (how this happens I'm not quite sure, bio 101 didn't cover that).
Also if you have done a large amount of damage to your muscles and I mean an absolute massive amount, your kidneys actually begin to fail at doing their job. You see when you exercise you damage muscle fibers, we all know this, however those cells you damage spill their contents in to the blood stream. Now most of the time the body recollects the proteins and enzymes and puts them back to use, but if you do a lot of damage and I mean a **** load, your body can't possibly collect all the protein and enzymes floating around in the blood. This is why you can have high AST and ALT levels on a liver function test and have a perfectly healthy liver, because those 2 enzymes are found in the blood after cellular damage. So the protein and enzymes in the blood that your body can't pick back up make their way to your kidneys. Now the kidneys are actually very complicated but in essence 20% of everything that passes through them is discarded, and then the useful stuff is reabsorbed. But when you have tons of proteins and enzymes floating around in the blood, when 20% of that is discarded, there's not enough "helpers" to go out and grab the protein that was discarded, so your pee becomes brown. Protein has leaked out of the kidneys in to your urine because there's just so much of it in your blood. This condition is called Rhabdo and it's often experienced by marathon runners who don't properly train.