I often get cramps in my legs when I am jogging. What could be causing them and what should I do?

-Maria from Oregon

Many people who experience muscle cramping suspect that they are not eating enough of a specific nutrient. They think that if they pinpoint the missing nutrient, then they can take a supplement and the cramps will go away. In fact, it is not always so simple.

Cramp as a result of dehydration?

Muscle cramps are often associated with dehydration, so the first step is to ensure you are drinking enough water. Your urine should be clear or a very pale yellow. Also, reduce or eliminate caffeinated beverages and alcohol because they cause water loss. During your runs, drink 8 ounces of water every 15-20 minutes.

Cramp due to a lack of calcium?

If you have ruled out dehydration as a cause of cramping, there are a few other factors to consider. Calcium plays an essential role in muscle contractions. Though it is unlikely that you have a calcium imbalance that would cause cramping, you can rule out the possibility by consuming dairy products or calcium-fortified foods at least twice each day. Even if this doesn’t help your cramping, it is good nutritional practice anyway.

Potassium and/or sodium deficiency leading to cramp?

Another possibility is an electrolyte imbalance, which can result from a potassium and/or sodium deficiency. Potassium and sodium are electrolytes, and they are essential for proper muscle function. If you restrict sodium intake (by restricting salt or salty foods), and also lose sodium through profuse sweating, these losses can be significant enough to create an imbalance and contribute to cramping. If you follow a low sodium diet, try liberalizing it to see if the cramping eases up. Losing significant potassium through sweat is unlikely even for a marathoner, but a diet low in potassium could over time lead to potassium imbalance. To prevent this, eat potassium-rich foods such as bananas, potatoes, yogurt, oranges and raisins frequently.

Erica Lesperance, RD, LD Contributing Expert

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