I thought this was a great comment by Nancy on my last post. She explained this facet of hydration much better than I could of and thought it worth while to post it.
"You and I keep learning this one again and again. :)
A couple technical things....Caffeine from pop is a diuretic [From Webster's Dictionary: tending to increase the excretion of urine], so you will actually lose ground on hydration even though you are drinking.
Also, less water in your system means less water in the blood. Most athlete's blood volume actually increases to be able to carry more oxygen and meet your increased needs. So if you are low on water and your blood volume goes down, that means the blood is thicker and harder for your heart to pump around, less oxygen gets to your muscles and tissues, and so you are working harder and not getting the results. Does that make sense?
It helps me to think of it this way, especially when I want a pop. I have decided that pop is a treat and I need to hydrate over and above if I am going to drink it."
Great comment Nancy. I will hope to use your method and think of this before drinking my next soda, but we'll see. I tend to go in spurts, I always have. I will drink nothing but water for months and then all of a sudden I will switch and drink nothing but soda. And so on the cycle continues. Sometimes I even think "I need to stop drinking soda so much" and then reach for the can of Dr. Pepper and open it up. Strange. Anyway, some great info.