MYTH #4: YOU NEED EIGHT 8-OUNCE GLASSES OF WATER EACH DAY.
The Institute of Medicine recommends about 91 ounces (a little more than 11 8-ounce glasses) of fluid daily for women. But here's the thing: It expects 80 percent of that to come from water, juice, coffee, tea, or other beverages and the remaining 20 percent from food. That means if you drink a 12-ounce cup of coffee and a 12-ounce can of diet soda, you only need 48 more ounces (three 16-ounce glasses, or four soda cans' worth) for the day.
MYTH #5: AFTER AN INTENSE WORKOUT, BOTTLED WATER IS BEST.
There's a reason volunteers hand out Gatorade during marathons. If your workout lasts longer than an hour, you need to replace the water and electrolytes, such as sodium and potassium, that you've lost (that's what sports drinks generally do). For less intense workouts, regular water is fine.
MYTH #6: WATER BOTTLES ARE EASY ON THE ENVIRONMENT BECAUSE THEY CAN BE RECYCLED.
Wouldn't it be nice? And it's not just the bottles. Eco-costs include manufacturing, trucking, shelving, and marketing. And meeting the annual U.S. demand for plastic bottles requires enough oil to keep 100,000 cars on the road for a year, says Janet Larsen of the Earth Policy Institute. Sure, the 70 million empty water bottles the U.S. produces per day can be recycled, but the sad truth is, about 86 percent of them end up in the trash. Hardly worth it, for what flows out of the tap and into a reusable glass for free.