Drinking six to eight glasses of water each day is healthful, most health experts agree. But apparently not everyone is on the same page.
A general practitioner from Scotland says that health advice is “thoroughly debunked nonsense” and is propagated by bottled water companies out to make a profit.
In a commentary published online in the British Medical Journal, Margaret McCartney quotes experts that say drinking too much water can cause hyponatremia (low sodium levels in the blood) and expose people to pollutants. And the public health push makes people feel guilty for not drinking enough.
Experts were quick to pounce on the commentary as being misleading. The article hadn’t been peer-reviewed, pointed out Thomas Sanders, a professor of nutrition and dietetics from King’s College London. Sanders wrote in a reply on the BMJ website:
“Appropriate hydration is particularly important for the elderly and the very young and for most people it is better to obtain most fluid intake from water, whether bottled or tap water, than from other beverages (especially sugar containing and alcoholic beverages). … MacCartney [sic] focused on the more whacky claims made for water and appeared to cherry pick her references to make a story.”
While the headlines duke it out, it’s worth offering a refresher—how much water do we need every day?
The answer isn’t cut and dry, says an article by the Mayo Clinic, and depends on your exercise level, health conditions and the heat and humidity of your environment. In general, the Institute of Medicine recommends about nine cups of beverages for women and 13 cups for men.
The Mayo Clinic offers another way to assess if you’re getting enough H2O:
“If you drink enough fluid so that you rarely feel thirsty and produce 1.5 liters (6.3 cups) or more of colorless or slightly yellow urine a day, your fluid intake is probably adequate.”
The issue of too much water surfaces among athletes, especially marathon runners. Hyponatremia is a real concern when replacing the water lost during sweating—too much water, and the salt imbalance in the body can cause cells to swell with water, which is particularly dangerous for brain cells. Hyponatremia symptoms include confusion, nausea and convulsions, according to MedlinePlus. It can also occur in the elderly and hospitalized patients. Some 3.2 to 6.1 million patients get hyponatremia each year, and the condition is associated with congestive heart failure and cancer.
To avoid the condition, this MedlinePlus article says:
“If you play any demanding sports, drink fluids that contain electrolytes (“sports drinks”). Drinking only water while you take part in high-energy athletic events can lead to acute hyponatremia.”
And water chugging competitions can be deadly too. One woman who drank 6 liters of water in three hours for a radio show died from hyponatremia.