Do you really need 8 glasses of water per day?

Drink eight glasses of water every day for good health. \nThat’s always been the standard. Not everyone always needs that much, though, said Alice Lindeman, an associate professor in IU’s Applied Health Science Department.\nLindeman said the amount of water a person needs to drink per day depends on a number of factors, such as the type of foods the person eats and their activity level. Someone who is on a high protein diet will produce a lot of waste and therefore need a lot of water to stay hydrated. Someone on a high fiber diet will also need more fluid to prevent constipation, since fiber holds fluid.\nMedications may also affect the amount of water someone needs to consume, Lindeman said. For example, certain kidney medications or antibiotics such as gentamicin require patients to drink more water when taking them. \nA person’s fitness level also plays a role. \n“The more fit you are, the more metabolic muscle mass you have,” Lindeman said, “so you need to drink more water.” \nLindeman said even gender and age are factors in determining the amount of water a person needs to drink. \nMen have more lean muscle mass than women, which means they sweat more, lowering their body temperature. Because of this, men often need to drink more water than women, she said. Kids and the elderly also need to drink more water to keep their bodies adequately hydrated. \nSo when should someone drink water? \nLindeman said she recommends that people use thirst as their mechanism. She said that by the time someone is thirsty, that person is dehydrated by one percent of their body weight.\nAlyce D. Fly, an associate professor in the Applied Health Science Department, said exercise also makes a difference.\nA person needs to drink about one to 1.5 milliliters of water for each calorie of energy burned. \nSo if someone is doing strenuous exercise, that person will need to drink more water than someone who is being inactive, Fly said. \nBut she advised that people can drink too much water in a day, and that some fluids can come from food. \n“Just because it’s not in liquid form doesn’t mean you aren’t getting any liquids,” Fly said. \nAnd despite the importance of drinking water, Lindeman said that it isn’t always the best liquid for quenching thirst. \n“When I wake up in the morning no cup of water is going to hydrate my thirst,” she said.