May 6, 2014
Cramping Your Style
By:  Lisa Dorfman, MS, RD, CSSD, LMHC, The Running Nutritionist® Muscle cramping has cost athletes great workouts, Olympic medals & probably even our troops during battle contributing to a billion dollar sports drink industry to manage the losses associated with sweaty sweats. Although cramping can be caused by a number of reasons, nutritionally it is often due to the loss of electrolytes in sweat. Electrolytes are minerals like sodium and potassium, which are added to most sport drinks. The electrolytes also include other minerals such as calcium, magnesium, and chloride. These electrolytes send messages to nerves and muscles throughout the body. Electrolytes are involved with muscle contraction and relaxation while you’re training, so an imbalance can impact the actual contraction of the muscle itself. Sodium losses through sweat are the most common cause of cramping, but potassium losses can lead to cramping too. Excess water replacement in the absence of supplemental sodium during extended training can lead to hyponatremia or decreased plasma sodium concentrations. Research suggests that exercise-induced hyponatremia may also result from fluid overloading during prolonged training.  Hyponatremia is also associated with calorie conscious fitness enthusiasts who drink plain water in excess of their sweat losses or who are less physically conditioned and produce a more salty sweat. The challenge is that when blood is diluted of sodium, your thirst drive is affected too, so the key is to rehydrate with fluids that replace sodium-like sport drinks. Sodium can be consumed in food such as pretzels, baked chips and salted almonds and by salting your food at mealtime. Potassium is another electrolyte involved with maintaining body fluids. As the major electrolyte inside the body’s cells, potassium works in tandem with sodium and chloride to maintain body fluids and generate electric impulses in the nerves and muscles including the heart. Loss of potassium from muscle has been linked with fatigue. Although potassium supplements are not necessary, finding sport drinks and recovery beverages that include potassium is one way of meeting your needs. Sports drinks contain sodium and potassium in various amounts to prevent cramping. Whole foods with electrolytes like fresh fruit and vegetables, low sugar sports drinks or coconut water are three natural ways to replace electrolytes lost in sweat. Adding baby foods like baby bananas to a fruit smoothie is one way you can add a few hundred milligrams of potassium to your diet. The baby food will also help thicken the drink without excessive sugars. Another electrolyte, magnesium, is required for hundreds of functions in the body. For athletes, the most important are energy production, oxygen uptake by muscles, and electrolyte balance. Magnesium also helps the heart to beat steady, supports your immune system, keeps bones strong, and is involved in protein synthesis required for building muscle. In addition, research suggests that deficiencies in magnesium can affect performance, amplifying the stressful effects of high intensity exercise on cells. High intensity exercise can increase urinary and sweat magnesium losses by 10 to 20 percent. Seven out of 10 individuals are deficient in magnesium so if you detest greens, beans, nuts, and whole grains you’re really at a lost.