Your body comprises of more than two thirds water. Water is uses to process waste, regulate body temperature, lubricate and cushion the joints. It is lost through breathing sweating and digestion. The Institute of Medicine recommends that men drink 13 cups (3 liters) of total beverages a day and women drink 9 cups (2.2 liters) of total beverages a day.
What is the optimal time to drink water?
1) In the morning
It is advisable to drink two glasses of water upon waking to re-hydrate.
2) Before a meal
Drink one glass of water 30 minutes before a meal to help digestion. Drinking too much water with your meal will dilute the digestive juices. If you do drink at meal time only drink a small amount and make sure it's room temperature. Leave an hour after a meal before you drink again (Pitchford, 2002).
3) Before sleep
Drink one glass of water an hour before bedtime will help you to stay hydrated.
The American Heart Association says "Keeping the body hydrated helps the heart more easily pump blood through the blood vessels to the muscles. And, it helps the muscles remove waste so that they can work efficiently."
“If you’re well hydrated, your heart doesn't have to work as hard,” says John Batson, M.D, a sports medicine physician.