Is Being Overhydrated Dangerous?

Drinking too much water is less common than underconsuming it, but the consequences of extreme overhydration can be as dangerous as those associated with dehydration. (You may remember the headlines in the 2000s and 2010s warning marathon runners of the “deadly dangers” of overdoing their water intake.)

That’s because overhydration can dilute sodium levels in the blood. This can cause conditions like hyponatremia (an electrolyte imbalance) and water intoxication (a rare phenomenon that occurs when water intake exceeds the amount of water excreted by the kidneys).

“If you’re chugging gallons of water to power through long workouts, it can flush out necessary minerals,” explains human-performance advisor Will Maloney, national program manager for virtual training at Life Time. “One can oversaturate cells when drinking more than what is needed, and this won’t help with hydration.”

“When the sodium levels start to drop, the first thing people notice is they start getting angry,” says salt expert Darryl Bosshardt, BS, of Redmond Real Salt. “They start getting short with people. Then they get a headache. Then they’ll start getting muscle cramps; digestion starts to go. It’s just a cascade.”

Left unchecked, that cascade can culminate in hyponatremia, in which the sodium levels become diluted, which in turn causes swelling in cells throughout the body, including the brain. As pressure increases within the skull, so does the risk of coma, brain damage, and even death.

This is not a concern for folks who work out once a day for an hour or less and recover with food and water. But for endurance runners, cyclists, hikers, and other athletes who exercise for hours or even days on end, maintaining a fairly precise blood chemistry can be extremely important.

This was excerpted from “Drink Up” which was published in the May 2022 issue of Experience Life magazine.