No doubt you’re ramping up your race-season nutrition plan to include enough carbs and healthy fats to fuel hardworking muscles, enough protein to rebuild them, and plenty of fluids to stay hydrated and energized for every run. That’s good.
But what about electrolytes—those electrically-charged minerals like sodium, potassium and calcium, that keep all the systems of the body functioning like a well-oiled machine? How do you get enough of these all-important minerals to maintain your health and enhance your performance? How do you know when you're running low on electroltyes and the best way to replace them?
To find out, we talked to Katie Jeffrey, a registered dietitian, Board Certified Specialist in Sports Dietetics, and owner of FitNutrition.
“Electrolytes produce electrical impulses in the body," says Jeffrey. That makes them vitally important to a number of biochemical processes, including balanced blood chemistry, healthy blood pressure, and the proper functioning of muscles, nerves and heart.
“Runners and other endurance athletes lose electrolytes in their sweat, making it especially important that they get enough in their diet,” says Jeffrey.
Muscle cramping is likely first to come to the minds of many runners worried about replenishing electrolyte levels.
Low electrolytes aren’t the only cause of muscle cramps, but Jeffrey says a deficiency in certain electrolytes, combined with dehydration, is certainly one of them.
“Improper fluid intake as well as a inadequate intake of sodium, potassium and calcium can increase one's risk for cramping,” says Jeffrey.
So, how do runners know when they need to replenish their electroltye levels?
According to Jeffrey, if you’re a casual runner who’s eating a diversity of nutrient-rich foods and staying hydrated, you probably don’t need to take special steps to replace electrolytes before or after you run.
“A well-rounded nutrition plan provides most casual athletes with all the electrolytes they need,” says Jeffrey.
“But if you know you sweat heavily, run in hot temperatures or heavily-layered in cold temps, or if you run longer than one hour, start consuming a sodium-enhanced sports drink or tab an hour before your run, and then every 10 to 20 minutes throughout your run, depending on how heavily you sweat.”
Is it possible to get too many electrolytes?
“It’s possible,” says Jeffrey. “But it’s hard to overdose on electrolytes from food. The people who get too much normally do so because they’re taking too many or too high a dose of supplements” says Jeffrey.
“For example, too much sodium chloride (salt) can cause high blood pressure in people who are salt sensitive,” says Jeffrey. “And someone who takes too much calcium may eventually develop kidney stones or even iron deficiency—a certain recipe for fatigue.”
Here’s a look at some of the more common electrolytes, how they impact health, performance, and how to get enough of them into your diet.
“Of all the electrolytes, this is the one runners and other endurance athletes lose the most of in sweat,” says Jeffrey. “Sodium chloride (common table salt) facilitates thirst and helps the body retain fluids. It also helps maintain a normal blood pH.”
Sodium chloride also supports the function of nerves and muscles, and, together with potassium, maintains the right balance of fluids both inside and outside of cells.
Most people, including casual runners, get enough, if not too much, salt in their diets. But, again, if you run longer than one hour, it’s important to replace this electrolyte afterwards.
“Depending on how heavily they sweat, runners lose on average of around 900 mg to 2,500 mg of sodium per hour. You can replace that by adding about a teaspoon of table salt (for 2,330 mg of sodium) to your water, coconut water, or favorite sports drink, if it doesn’t already contain sodium,” says Jeffrey.
Another factor to consider when replacing sodium chloride: some runners lose more salt in their sweat than others.
“Some runners are saltier sweaters than others,” Jeffrey says. How do you know if you’re a saltier sweater?
“Hang your running hat or shirt to dry after a hard run. If a white, crusty residue forms, that’s a good sign you’re a salty sweater, and may need to take additional steps to replace this electrolyte after a hard run,” says Jeffrey.
You can do that with salty snacks like pretzels, baked chips, cheese or with a sodium-enhanced sports drink or tab. Soups and milk are good sodium sources to include in your general diet or as part of a post-run recovery meal.
“This electrolyte helps support heart function and muscle contractions,” says Jeffrey. Because it conducts electrical impulses, potassium facilitates communication between nerves and muscles.
It also facilitates the transport of nutrients into cells and promotes glycogen storage. (A good thing since glycogen is what fuels muscles.) Potassium can also help counter sodium’s negative impact on blood pressure.
Potassium deficiency is fairly rare since the body stores ample amounts, it’s easy to get enough from food, and we don’t lose a lot of potassium, even during hard exercise.
Bananas, sweet potatoes, dark leafy greens and oranges all contain lots of potassium. Include these foods every day or as part of your post-run recovery snack, to keep your potassium levels up to snuff.
Calcium is another electrolyte that performs several important functions. It plays a vital role in the contraction and relaxation of blood vessels and muscles, and supports nervous system function.
“It also builds and maintains strong bones and teeth and supports the function of the heart,” explains Jeffrey. "Calcium is abundant in dairy foods, dark leafy greens, and some nuts and seeds."
How much calcium you need depends on your age and other factors. Some people take calcium supplements, which is fine if they’re eating a calcium-poor diet, but mega-dosing with calcium supplements could potentially cause health problems.
Make sure you get plenty of vitamin D along with your calcium, as this vitamin helps your body absorb calcium.
This electrolyte helps the body produce protein, facilitates the function of some of our enzymes, boosts energy, and helps muscles to contract and relax.
“Along with potassium, magnesium also plays an important role in maintaining healthy blood pressure and heart function,” says Jeffrey.
Magnesium deficiency is rare, but can occur in some people, causing symptoms ranging from drowsiness and muscle weakness (mild deficiency) to hallucinations and numbness (severe deficiency).
Good sources of potassium include dark leafy greens, nuts, avocados, bananas, and whole grains.
Another electrolyte with several important jobs, phosphorus boosts energy by helping the body use carbohydrates and fats. Phosphorus also facilitates the production of protein the body needs to maintain and repair tissues and cells, and helps muscles contract.
Although a phosphorus deficiency is rare due to its abundance in food, a lack of this electrolyte can cause “fatigue, muscle weakness and irregular respiration and heart rate,” according to Jeffrey.
Best foods for phosphorus include meat and dairy products, although a small amount of phosphorus can be found in fruits and vegetables.