Colin Anderson for Getty Images
Colin Anderson for Getty Images

Every trend has fans that take it to the extreme. We’re always told to drink more water, but too much of a good thing is bad for you, even water.

“Some people are such water drinking devotees that they are aquaholics, resulting in overhydration,” explains Dr. Christopher Calapai, a New York City osteopathic physician certified in family medicine and anti-aging medicine. “As a result, experts now fear we’ve become so focused on staying hydrated that we’re guzzling water to life-threatening extremes.”

The H2O “abusers” tend to be dedicated athletes who sweat enough to upset the balance between water and sodium in the blood, and adding a lot of plain water only makes the situation worse. Others are over-quenching thirst caused by medications they’re taking that give them a dry mouth. Still others may have psychological conditions that lead to compulsive water drinking or have a medical condition that causes excess water retention even when the water intake would be fine for a normal body. In all cases, the kidneys can’t keep up with ridding the body of the water through urine.

In the early stages, symptoms of overhydrating include:

  • Nausea and vomiting
  • Headache
  • Changes in mental state—confusion or disorientation

When the overhydration becomes more severe, creating dangerously low levels of sodium in the blood, called hyponatremia, symptoms progress:

  • Muscle weakness, spasms or cramps
  • Seizures
  • Unconsciousness
  • Coma

If you’re an endurance athlete, don’t just rely on thirst, Calapai advises. Instead, spread your drinking out. Drink before and during the race or workout, not just afterward, so that you’re drinking no more than one liter per hour. Calapai also recommends sports beverages that contain electrolytes—sodium and potassium—which are both lost in sweat. When you wake up, start drinking slowly, Calapai advises. Don’t start your day with three cups of water or juice. Learn to sip!

Calapai suggests three approaches to determining how much water you need:

  1. Weigh yourself daily for a week to check hydration. “Your body weight shouldn’t fluctuate too much,” he notes.
  2. Notice how much you pee—and its color—in the morning. There should be a large amount of pale or clear urine.
  3. Aim to wake feeling hydrated. If you’re thirsty when you get out of bed in the morning, you may not be consuming enough fluids.

Choose low-sugar sports drinks—no more than 5 grams of sugar per 8-ounce serving. “Even natural drinks like coconut water have too much sugar and potassium to hydrate,” Calapai says.
Coffee, tea and watery fruits and vegetables count toward fluid intake. “Caffeine is not a diuretic,” Dr. Calapai says. “It’s about volume, so if you drink five cups, you’ll pee more.”

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