Improving Tennis Stamina Through Electrolyte Supplementation
May 12, 2015
Salt and endurance:What are electrolytes for? Electrolytes play a variety of roles in the human body, from regulating blood volume to assisting with nutrient absorption. Because of electrolytes’ role in helping muscles contract and release, low electrolyte levels are often thought to contribute to cramping. Narrowing our focus to endurance, it is important to remind ourselves that endurance sports are essentially muscle contractions (the pull of a swim, the stroke of a pedal, the step of a run, etc.) repeated many, many, many times. Each contraction requires the use of electrolytes, and each contraction produces heat, which raises core body temperature. In effort to cool itself, the sweat glands release a mixture of water and electrolytes (mostly sodium) to rid itself of excess heat. Lastly, during exercise, the body is burning calories as energy. The longer the duration of the activity, the greater the fluid, caloric and electrolyte loss, and therefore the greater the importance to follow some strategy to replace components in all three categories. This is why tennis coaches tell their players to drink sports drinks and eat bananas during practice and matches. What happens when your body runs low on calories, water or electrolytes? Put simply: bad things. Because your body needs food, water and salt to perform, you will be forced to stop or slow down when you run low in one of these categories. Too few calories? You’ll run short on glucose, which is the “energy” for your muscles, and you’ll be forced to slow down or stop to allow your body to shift to burning fat (via conversion to glycogen). Too little water? You’ll get dehydrated, and again be forced to slow down or stop. Low electrolytes? You’ll run the risk of an even more dangerous scenario than dehydration -- hyponatremia, which happens when your water levels are too high and salt levels are too low. It usually results from some form of over-zealous “water-only” hydration plan (such as sports drinks with very low levels of salt or -- worse -- plain water), and it will likely be accompanied by confusion, irritability, headaches that won’t go away, nausea or extreme weakness. If you display any of these symptoms, it’s critical to take immediate steps to restore the proper ratio of electrolytes in the body, and in severe cases, medical attention. What does all this mean? Essentially, if you’re running low on electrolytes, your performance is going to suffer. Taking steps to replace all of your electrolytes -- sodium, potassium, magnesium, calcium and chloride -- is an important step to getting the most out of your body on match day.
Are there any studies that back this up?Glad you asked! We recently published a blog post about a study in Spain that examined the effects of electrolyte supplementation on endurance performance. Check out the original blog post for greater detail, but a summary is below: The study: Researchers at UCJC divided 26 triathletes into two groups. The first group completed a medium-distance triathlon (the segments added up to approximately a 2K swim, 90K bike and 21K run) consuming sports drink as they usually would, but also consuming SaltStick Caps in order to replace sodium lost through sweat. The second group completed the same distance while consuming sports drink as they usually would, but they received a placebo capsule with no extra sodium. Researchers were aiming to replace about 70 percent of sodium in the first group, but only about 20 percent in the second group, the sole difference due to the electrolyte capsules. When the triathletes completed the race, researchers tallied up finishing times and found that the triathletes who consumed the sodium tablets finished in an average of 26 minutes (8%) faster! The increase in speed usually came from improved cycling and running times, which come later in the race after electrolyte levels begin to decline. Key takeaways:
- Consuming sports drinks isn’t enough: Most people’s sweat contains sodium at a concentration of 40-60 mEq/L, and in order to stay hydrated, an athlete should replace salt and water and a similar concentration. However, many sports drinks are only concentrated at a 20 mEq/L level (increasing sodium beyond this level results in a less pleasant taste, closer to sea water). What does that mean? It means supplementing with a sports drink may only replenish half of the necessary salts. And as we wrote earlier, low electrolyte levels can hurt performance.
- Additional electrolyte supplementation had a measured, statistically significant improvement on performance: The 26 athletes were matched for age, anthropometric data, and training status, and randomly placed into the two groups, reducing the chance for measurement error.