How drinking too much water can be dangerous, even deadly

Staying hydrated when participating in warm weather activities or simply spending time outdoors in the summer is essential.

Drinking water can keep your body temperature around normal, which can help mitigate the risk of dehydration as well as suffering from heat illness.

However, there are occasions when people can actually consume too much water, causing them to overhydrate and become ill.

Dr. Matthew McElroy, a sports medicine specialist and primary care doctor with Geisinger Health Systems in Pennsylvania, said overhydration is something that first started coming onto the radar about 10-15 years ago.

The problem with drinking too much water, is that it dilutes the sodium in your blood. Sodium counts are real critical to muscle function, as well as brain function, McElroy told AccuWeather.

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"The primary issue of having too much water is you drown in your own water a little bit, it dilutes your sodium in your blood and your biggest risk is that it can cause a change in the way your brain works," McElroy said.

When sodium levels in your blood are abnormally low, that can lead to a condition called hyponatremia. This occurs when the kidneys become overwhelmed and it becomes difficult for them to excrete water. Symptoms of hyponatremia can range from mild to life-threatening, according to the Mayo Clinic.

Medical experts say overhydration is more common in endurance athletes, such as marathon runners, who exercise outdoors in intense heat for longer periods of time such as over two to three hours.

A 2005 study in the New England Journal of Medicine found that 13 percent of runners in the 2002 Boston Marathon who provided blood samples had hyponatremia.

Beth Kitchin, Ph.D, an assistant professor with the University of Alabama at BirminghamDepartment of Nutrition Sciences, said people should drink about 4 to 6 ounces of water every 20 minutes when performing an activity, whether it's gardening or running a marathon.

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"You don't need gallons of water during activity, which is where some people have gotten into trouble with overhydration," she said.

The Centers for Disease Control states that the average adult should consume about 3 to 4 liters of water daily from drinking fluids and eating food.

Elena McCown is an ACE certified health coach and fitness instructor based in Franklin, Tennessee, who often coaches marathon runners. She frequently tells clients that while water is important and vital to life, more is not always better in certain circumstances.

"Hyponatremia occurs more frequently in females, the elderly, and those who are hospitalized or have specific risk factors," McCown said. "I tend to see it more often in people who are running marathons, are a little slower, and tend to over compensate by drinking too much water and not taking in enough electrolytes."

To find the proper balance between hydrating and overhydrating, it's best to drink to your thirst level, while also consuming sports drinks that contain electrolytes.

The body loses sodium when people sweat during exercise. Both McCown and McElroy said adding additional levels of sodium to your diet right before an endurance event is another way to help counterbalance the risk of suffering hyponatremia.

Consuming foods like soup or adding about a teaspoon of salt to some of the foods that you eat can provide a boost to sodium levels.

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"If you plan to work out several days on end, in really hot weather you're probably not gonna get enough salt into your body to match the salt you're sweating out, so you should think about adding a little salt to the things you eat," McElroy said.

"A normal blood sodium level is between 135 and 145 milliequivalents per liter (mEq/L). Hyponatremia occurs when the sodium in your blood falls below 135 mEq/L," the Mayo Clinic states.

Experts recommend weighing yourself before and after exercise. Kitchin suggested drinking 16 ounces of water for every pound lost.

McCown said if you weigh about 1 pound more after exercise, you should cut back on water a little bit, whereas if you weigh about 5 pounds less, you should consider drinking a little more.

While rare, cases of hyponatremia have been blamed for the deaths of athletes in the past.

In 2002, a 28-year-old woman running in the Boston Marathon collapsed during the race and died two days afterward.

In 2014, two high school football players in the southern United States reportedly died due to overhydration.

"Athletes are usually pushed to drink as much water as possible to avoid dehydration instead of listening to their thirst. This can lead to overhydration if not careful. Education and prevention are key with this problem," McCown said.