You’ve heard it countless times before: “drink eight glasses of water a day” or around around two litres of water. But just how strictly should this be followed?
In truth, there really aren’t any hard scientific evidence to support the “8 glasses of water” rule; it's not a one-size-fits-all situation. The amount of water you drink is dependent on several other factors, like how active you are, for starters.
Our bodies are made up of 60 percent water. To give it more gravity, every system in the human body needs water to function, from carrying nutrients to cells, flushing out toxins and keeping tissues in top shape. It’s so vital for the body to function well that even mild dehydration can drain you of energy and make you feel sluggish.
But there is such a thing as overhydration. “Saying that you should drink more water than your body asks for is like saying that you should consciously breathe more often than you feel like because if a little oxygen is good for you then more must be better,” says Dr. Chris van Tulleken in an article for BBC News where he is also a regular presenter.
“Contrary to many stories you may hear, there’s no real scientific proof that, for otherwise healthy people, drinking extra water has any health benefits,” says Aaron E. Carroll, professor of pediatrics and assistant dean for research mentoring at Indiana University School of Medicine, in an article for The New York Times.
So, how much water should you drink? For most individuals, the Institute of Medicine recommends 13 cups (3 liters) of total beverages a day for men and 9 cups (2.2 liters) for women. Keep in mind that “beverages” don’t just pertain to water; juices, tea, coffee and the like count, too.
“In general, you should try to drink between half an ounce and an ounce of water for each pound you weigh, every day,” Trent Nessler, PT, DPT, MPT, managing director of Baptist Sports Medicine in Nashville, told WebMD.
The recommendations above, however, are not set in stone. If you’re pregnant or breastfeeding for example, you may need to drink more. Modify your daily intake of water depending on these factors:
Pregnant or breastfeeding Many changes happen to a woman’s body when she’s pregnant or breastfeeding. Because of this, pregnant and breastfeeding women need additional fluids to stay hydrated. The Institute of Medicine recommends that pregnant women drink 10 cups (2.3 liters) of fluids daily and breastfeeding women drink 13 cups (13.1 liters) of fluids a day.
Exercise You lose water every day through your breath, urine, bowel movements and perspiration. People who engage in any activity that makes them sweat should especially make it a point to replenish the water they lose by drinking more. For those engaging in intense exercises, sports drinks that contain sodium are best.
Environment One way the body regulates body temperature is by perspiring. Hot and humid weather can make you sweat more requiring more fluid intake. In the Philippines, heat stroke and dehydration is a serious concern during the summer months. It’s especially a threat to young children and the elderly. Don’t forget to drink more water during the summer season and remind those around you to do so as well.
Illnesses Fever, vomiting and diarrhea can cause additional fluid loss. Certain illnesses and health conditions also require additional fluid intake like bladder infections and urinary tract stones. Kidney, liver and adrenal diseases, on the other hand, may require less fluid intake.
What it boils down to is following your thirst instinct, saysDr. David Perlow, a urologist. Afterall, your body knows best.