1. [your weight] ÷ 2 = N
2. .20 x N = X
3. X + N = How many fluid ounces of water you should drink per day
4. Divide by 8 to find out how many 8 oz. glasses of water is adequate.
So for example, let's take a 130 lb. person:
1. 130 ÷ 2 = 65
2. .20 x 65 = 13
3. 65 + 13 = 78
4. 78 ÷ 8 = 9.75
So basically (if you're looking for a shortcut), move the decimal place of your weight over once to the left, and add that to whatever half of your weight is. :)
It also said that if your body isn't used to drinking that much water, then you should gradually ease into it in a 2-4 week period. If you don't, your body will retain more water (only at first -- it will stop) and your kidney could be overworked.
I'll try to get the article from my teacher the next time I have gym, which is Thursday. I hope somebody finds this interesting. I'd be interested to know how much water everybody drinks in here and whether or not they're on, above or below the recommended amount from this article.