The loss of electrolytes such as sodium and potassium through sweat can lead to muscle cramps, nausea, vomiting and even death.
Electrolytes are minerals (sodium, potassium, calcium, magnesium, and chloride) which send messages to nerves and muscles throughout the body, and are involved with muscle contraction and relaxation during exercise, so that an imbalance can impact the actual contraction of the muscle itself.
Sports drinks contain sodium and potassium in various amounts to prevent cramping.
If your child loses a great deal of salt in his sweat, he is losing the electrolyte sodium, which is critical for muscle contraction. Some athletes are "salty sweaters" who lose more salt than the average athlete. During the summer months, players who cramp appear to lose more than double the sodium in sweat than players who don't cramp.
How does your child know he is a salty sweater? Here are some of the signs:
- Sweat that stings the eyes
- Sweat that burns in an open cut
- Sweat that tastes salty
- A gritty feeling on the skin after a practice or game
- Post-workout streaks of white on the face, skin, clothes, or hat (e.g "cake sweat")
When sodium levels become low, hyponatremia can cause cramping and other symptoms. Drinking too much water without replacing sodium can also cause hyponatremia.
Sports drinks replace lost electrolytes
When blood sodium levels are low, the thirst drive is affected too, so the key is to rehydrate with fluids containing sodium, such as sport drinks.
Sodium can also be replaced by eating salted snacks such as pretzels, baked chips, and salted nuts, and/or by salting food at mealtime.
Potassium is another electrolyte involved with maintaining body fluids. Potassium works in tandem with sodium and chloride (table salt) 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.
Young athletes typically don't eat enough fruits and vegetables, the primary sources of potassium.
- Although potassium supplements are not necessary, drinking sport drinks and recovery beverages that include potassium is one way of meeting a child's potassium needs.
- Eating bananas, oranges, tomatoes, cucumbers, cantaloupe and pears can add significant amounts of potassium to your child's diet.
- Coconut water is also an excellent way to get a large amount of potassium naturally (although a recent study shows athletes prefer the taste of a sports drink that coconut water).
A third 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 the immune system, keeps bones strong, and is involved in protein synthesis required for building muscle.
High intensity exercise can increase urinary and sweat magnesium losses by 10 to 20 percent. Young athletes are typically deficient in magnesium because their diets tend to be low in greens, beans, nuts, and whole grains. Once grains are bleached, stripped of the brown fibrous whole grain, magnesium is lost. Other foods rich in magnesium include almonds, soy, oatmeal and potatoes.
While hydration is essential for peak performance at any sport year round, electrolytes are essential for cramping prevention and overall muscle health.
Lisa Dorfman, MS, RD, CssD, LMHC, the Running Nutritionist®, is a licensed nutritionist, licensed psychotherapist, certified coach, Board Certified Specialist in Sports Dietetics, and a Board Certified Professional Counselor. She is an adjunct professor in the University of Miami Department of Exercise Sciences, and, as Director of Sports Nutrition and Performance for the Miami Hurricanes. A personal nutritionist for numerous professional athletes, Lisa is also national Olympic and Paralympics Team Nutritionist for US Sailing.