Electrolytes like sodium, potassium, chloride and magnesium are electrically charged minerals that are present in the body’s fluids (like the blood and urine) and are important for balancing the water in your body. They’re also essential for proper functioning of the nerves, muscles, brain and heart.
When you become dehydrated, the concentration of electrolytes in your blood rises, and the body signals the release of the hormone vasopressin, which ultimately reduces the amount of water that’s released into the urine so that you can reabsorb it back into your body and get that balance back in check, Dr. Hyndman said.
Unless you’re in an unusual circumstance — doing very intense exercise in the heat or losing lots of fluids from vomiting or diarrhea — you don’t need to replenish electrolytes with sports drinks or other products loaded with them. Most people get enough electrolytes from food, Dr. Hew-Butler said.
But drinking more water, even when I’m not thirsty, will improve my health, right?
No. Of course, people with certain conditions, like kidney stones or the more rare autosomal dominant polycystic kidney disease, may benefit from making an effort to drink a little more water than their thirst would tell them to, Dr. Topf said.
But in reality, most healthy people who blame feeling ill on being dehydrated may actually be feeling off because they’re drinking too much water, Dr. Hyndman speculated. “Maybe they’ll get a headache or they’ll feel bad, they’re thinking, ‘Oh, I’m dehydrated I need to drink more,’ and they keep drinking more and more and more water, and they keep feeling worse and worse and worse.”
If you drink at a rate beyond what your kidneys can excrete, the electrolytes in your blood can become too diluted and, in the mildest case, it could make you feel “off.” In the most extreme case, drinking an excessive amount of water in a short period of time could lead to a condition called hyponatremia, or “water intoxication.” “This is very scary and bad,” Dr. Hyndman said. If the sodium levels in your blood get too low, it can cause brain swelling and neurological issues like seizures, coma or even death.
In 2007, a 28-year old woman died of hyponatremia after reportedly drinking nearly two gallons of water over three hours while taking part in a radio station’s “Hold Your Wee for a Wii” contest, which challenged participants to drink water and then go as long as possible without urinating. In 2014, a 17-year-old high school football player in Georgia died from the condition after reportedly drinking two gallons of water and two gallons of Gatorade.