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Dr. Roach: The body keeps a tight rein on electrolytes in most situations


Dear Dr. Roach: Can you explain electrolytes? How can we make sure we keep our electrolytes in the normal range within our body? Are we wasting our money purchasing bottled water that says, “includes electrolytes”? I came across an electrolyte powder that can be added to water. Is this the best way to keep electrolytes in the normal range? How can we tell if we are taking too much electrolytes?

— A.R.

Dear A.R.: Chemicals that dissolve in water are called electrolytes when they break into charged particles called ions — they conduct electricity, hence the name. The most important electrolytes in the body are sodium, potassium, chloride, bicarbonate (the ionized form of carbon dioxide, dissolved in the water), magnesium, calcium and phosphate.

These are regulated by the body very carefully through wonderfully complex systems, and are kept in perfect balance most of the time. We get the overwhelming majority of our electrolytes from food. Most people need never worry about their electrolytes, nor do anything special to keep them regulated.

All water, except purified laboratory water such as distilled, contains some electrolytes. But when you pay for “electrolyte water,” there are a lot more electrolytes than in tap water. Most of the time, this is a waste of money, since your body regulates the electrolytes well through what you get in through food.

However, there are a few exceptions. One is athletes who are exercising at high intensity or for a long time, particularly in hot or dry weather. This can cause loss of electrolytes (especially sodium) through sweat, so endurance athletes need to consume more sodium, a positively charged electrolyte in its dissolved ionic form. It must always come with a negative ion, especially chloride (sodium chloride is table salt) or bicarbonate (sodium bicarbonate is baking powder). Athletes can buy powdered versions (usually packaged with a fair bit of sugar) or a premixed drink. Gatorade is an early example of an electrolyte drink.

Most people who don’t exercise at high amounts will do just fine drinking water. Drinking when you are thirsty, even while exercising, is safer. While we’re on the subject of drinking water, I prefer tap to bottled water, as there are no significant benefits to bottled water beyond taste in almost all of the U.S. and Canada.

Another example of people who need to pay attention to their electrolytes are those whose body systems are out of kilter, especially people with kidney disease or those who are vomiting or who have diarrhea. These groups often experience electrolyte disturbances. In a hospital, doctors spend a lot of energy correcting electrolytes by adding the appropriate supplemental electrolytes to a person’s intravenous fluids or orally. One of my professors always said, “The kidney is smarter than 10 interns,” since the kidney regulates electrolytes very well.

It is hard to get in too much electrolytes, but I occasionally see it. I know one person who drank an entire jar of pickle juice and felt really ill. But unless you have kidney disease (where excess potassium can literally be deadly), the body is smart enough to keep things in balance.

Readers may email questions to ToYourGoodHealth@med.cornell.edu.