Water, which composes about 60% of your body, delivers key nutrients to your organs. Working out (and sweating) sends it AWOL. So besides the two to three liters (nine to 13 cups) of water you need each day, I recommend drinking another eight-ounce cup when you work out. I drink bottled water (for fewer impurities); for taste, my brand is Evian.
Chugging before a workout can cause nausea. Instead, sip throughout your routine: between sets, after each rest period or at intervals during a bike ride, jog or walk.
I don’t recommend subbing sports drinks like Gatorade for H2O.Most contain lots of sugar, which turns to fat and can itself cause dehydration. Stick to the original.