Calcium is important for more than strong bones and teeth. It helps muscles deal and works well. For example, as you exercise, your muscles pull on your bones and break them down lightly. Then, as your body recovers, your bones use calcium to get stronger.
Magnesium helps you to move calcium and potassium into muscles to help in contraction and relaxation. It helps with energy production and supports organ function. Unfortunately, a hard workout leaves you depleted in magnesium and likely to have cramps, restless muscles, and spasms.
While coconut water carries more calcium and magnesium than other sports fruit juices and drinks, it is not a concentrated mineral source. As a result, coconut water contains less than 5% of your recommended amount of calcium and magnesium.