One of the functions of blood is to carry oxygen to the cells, and carbon dioxide away from them. Our bodies are one huge controlled fire or combustion. The key word is controlled. We do not erupt into flames and we do maintain a constant temperature which under most conditions is a hard balance to maintain. The formula is (in very general terms)
material to "burn" + 02 ===> CO2 + Water.
So the blood carries the oxygen in and you notice that one of the products is CO2 which the blood carries back.
You need to increase the oxygen content to the cells because they are using up a great deal of energy to do the exercise. More exercise, more energy more oxygen needed, more oxygen needed, more the blood needs to move around.
During exercise, your body may need three or four times your normal cardiac output, because your muscles need more oxygen when you exert yourself. During exercise, your heart typically beats faster so that more blood gets out to your body
Cnidarians: Jellyfish. Do not urinate on the stung though. This will only activate the stingers. Instead cool it in sea (salt) water and scrape away the remaining tentacles (or how you call it)
