You should drink at least six to eight 8 ounce glasses of fluid per
day plus one 8 ounce cup for each hour of
light activity.
Juices can be part of that, but keep in mind that they
can also be full of calories. Caffeinated beverages such as coffee,
colas, and teas don't count as part of your fluid intake because they
act as diuretics, they make you urinate more so you actually lose
water.
If you dont like the taste of water, try adding a wedge
of lemon or lime or a little juice for additional flavor.
Watch for warning signs of dehydration: Your nose and mouth may feel
dry, and your urine may turn dark yellow. Airplane travel can dry you
out because the cabin air has very little moisture in it. Bring your
own bottled water on the plane and be sure to drink it throughout the
flight.
Remember that humidity dehydrates you too. If hot, humid
weather is making you sweat excessively, grab an electrolyte
replacement drink such as Gatorade.
National Geographic - In the Womb
Paralumun New Age Village