- Scientists say the “8 glasses a day” rule may not be accurate for everyone
- The amount of water needed really depends from person to person
- It is best to listen to one’s thirst and ensure that urine isn’t any shade darker than lemonade
It has become a rule of thumb for many of us: eight eight-ounce glasses of water is the daily minimum requirement to hydrate our bodies.
Some scientists, however, believe that the “formula” to how much water a human body really needs is much, much simpler.
“Fluid needs are dynamic and need to be individualized from person to person. Factors such as sex, environmental conditions, level of heat acclimatization, exercise or work intensity, age, and even diet need to be considered,” Dr. Robert Huggins of the University of Connecticut told Health.
That’s right. The answer to how much water a body needs is simply: it depends.
Instead of fixed required minimum amount, a person is better off “listening” to one’s thirst, which basically means, if you’re thirsty, you get a drink.
An equally good indicator is the color of one’s urine. A person who receives the right amount of hydration should expect to have urine that is similarly in color to lemonade. Any shade darker means a person does not have enough water in his or her system.
Another question that often pops up is how much water is needed to replenish what is often sweat out during exercise.
For this, Dr. Huggins suggests calculating one’s “sweat rate.” Now, this is where it get a tad bit complicated because this involves a little experimentation.
First, a person would have to determine how much he or she weighs before the workout. Note, that a person should be hydrated before weighing in.
After the exercise, weigh in again, then find out how much weight you lost. Convert that number to kilograms and drink that amount of water in liters.
Dr. Huggins estimates that a person, on average, loses one to two liters of sweat for every hour of moderate intensity exercise.
He reiterates, however, that one should listen to his or her thirst.
There is, after all, the danger of over-hydration. Athletes could suffer exercise-associated hyponatremia that occurs due to electrolyte imbalance caused by drinking too much liquid. This often leads to nausea and vomiting, headaches, fatigue, and in serious cases, coma or even death.
“It is impossible to recommend a generalized range especially during exercise when conditions are dynamic and changing, there is not one size that fits all!” says Dr. Tamara Hew-Butler, who was the lead author of a study on hyponatremia published British Journal of Sports Medicine.
In all these, scientists recommend that individuals should stay within the right range and not under- or over-hydrate. The best method would still to be attune with one’s body and listen to one’s thirst.