Runners: Electrolytes and When to Replace Them


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." 

More: The Importance of Nuts and Seeds in an Athlete's Diet

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.

More: Are You Getting Enough Vitamin D?


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.

More: 8 Ways to Keep Muscle Cramps Away

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.

More: 10 Spring Fruits and Veggies to Add to Your Diet

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