Where does the human body store water?

Question

On a hot day, I can go out running for 30 minutes and lose 1-2 liters of water through sweat. (I can tell, because that's how much water I have to drink until I'm not thirsty anymore.)

Anyway, where was all of that water before I went out running?

Answer 1

Your cells do not store the water, the water is in the bloodstream, making it thinner (which is also why you bruise easier when you are hydrated) when you are excercising, the blood is pumping around your body faster, and only then does it get to the cells, and it helps with the metabolism of the cells. Water also gets stored in the stomach. When you sweat, it is not pure water, but a different substance secreted by glands on the skin, although it does contain a lot of water, so when you start to excercise the body realises it is getting hot, and so sends a command to withdraw water and take it to the surface so you can cool off.

Answer 2

in your cells

Answer 3

Actually, mush is right.  Most of your water is stored intracellularly.  When you get dehydrated, it's bad because your extracellular fluid is more hypertonic than the intracell environment and you tend to lose water from your cells to compensate for that loss, which is bad for your cells.  So, when you hydrate, you replenish those extracellular fluids and you decrease the concentration of solute there.  You'll notice that well-hydrated skin is also plump and soft--that's because your skin cells are maintaining the water content within cells...it's good for you to drink water!