Can a lack of salt cause muscle cramps?

"I've heard that my muscle cramps on longer runs can be caused by low salt levels? Is this true and why does that happen?"

Yes, low salt levels are one cause of muscle cramps during long runs. “Salt” generally refers to sodium, which is an essential electrolyte. During exercise sodium is lost in sweat and blood sodium levels drop. When this happens, the body regulates sodium levels and a cascade of hormonal changes occurs to bring sodium back up. In persons who are heavy or salty sweaters, the body may not be able to keep up with the amount of sodium being lost in sweat and sodium levels can drop dangerously low, called hyponatremia. Before sodium levels drop into ranges that can be called hyponatremia, muscle cramps and twitches may occur. To avoid these types of cramps, you may need to consume more sodium surrounding workouts.

The Mechanism

Sodium, along with other electrolytes, controls muscle contractions by triggering nerve impulses. When sodium levels drop, the nerve signals go haywire and a cramp is triggered.

That’s the theory at least. Researchers have explored how low sodium contributes to muscle cramps and results have been mixed. This is because muscle contraction is influenced by many variables, not just sodium.

Your Body Chemistry

If you are prone to cramps, consider all of these factors as you investigate the causes of your cramps. The “fix” for you is dependent on your body chemistry and therefore likely to be different than your running buddy’s. All of these variables influence muscle cramps:

• Sodium
• Potassium
• Calcium
• Magnesium
• Fluid intake
• Carbohydrate intake
• Body temperature regulation

The cause and solution for your muscle cramps is going to be a combination of these variables. The fun part of my job is helping you figure out which variables make a difference for your unique body.

Related Links

Make Your Own Sport Drink

5 Ways to End Muscle Cramps

Hana A. Feeney, MS, RD is your sport nutrition coach. As an open-minded, progressive dietitian that blends evidence based nutritional science with the principals of intuitive eating and cutting-edge functional medicine, Hana is your go-to nutrition expert. Hana specializes in sport nutrition, weight management, digestive health, fertility, hormonal health, and eating disorders. Visit www.NourishingResults.com to explore, read, cook and reach out!