Do you need Magnesium or Potasium in a sports drink?
Athletes can lose up to 2,000 mg of sodium (equivalent to 5 grams of salt) per liter of sweat, which is why sodium is the primary focus for athletes when fueling. Many sports drinks market their potassium and magnesium content, but do you really need these in a sports drink or running gel?
The short answer is no. The long answer is still no.
Potassium loss in sweat is approximately 200 mg per liter—only 10% of the sodium lost. This is equivalent to the potassium in half a banana or half a small flat white coffee. Unless you are sweating profusely every day and your diet is deficient in potassium, you don't need to supplement it through sports drinks. Consuming one serving of dairy and a couple of servings of fruits and vegetables daily is sufficient to meet your potassium needs.
Magnesium is also important for athletes, but it is the electrolyte lost in the smallest amount during sweating—just 12 mg per liter. This is equivalent to what is found in half a slice of bread or four almonds. Furthermore, studies have shown that magnesium supplementation does not directly improve exercise performance in individuals with adequate dietary intake (Bohl & Volpe, 2002). If your diet includes some fruits, vegetables, and grains, you will likely meet your magnesium requirements without supplementation.
In summary, sodium is the only electrolyte most people need to be concerned about during exercise. Magnesium and potassium in sports drinks are largely marketing gimmicks.
References
- Burke, L. M., & Cato, L. E. (2015). Sports Nutrition for Endurance Athletes. Australian Journal of Sports Medicine.
- Stofan, J. R., et al. (2007). Sweat and sodium losses in NCAA football players: A precursor to heat cramps? International Journal of Sport Nutrition and Exercise Metabolism, 17(1), 71-80.
- Sawka, M. N., & Montain, S. J. (2000). Fluid and electrolyte supplementation for exercise heat stress. The American Journal of Clinical Nutrition, 72(2), 564S-572S.
- Bohl, C. H., & Volpe, S. L. (2002). Magnesium and exercise. Critical Reviews in Food Science and Nutrition, 42(6), 533-563.