It's become a popular idea among endurance athletes that salt consumption during competition will help, but a new study finds no evidence that is true.
A small kernel of truth is involved in the belief, the authors write in the the Journal of Sports Science and Medicine - that there are sodium losses due to sweat during exercise and our bodies function on a principle of thermoregulation - but then some endurance athletes have taken that to believe they should consume large quantities of salt or other electrolyte supplements containing sodium during training and competition to improve performance.
That's not just drinking some Gatorade, it can result in excessive sodium intake, which is dangerous.
Thermoregulation refers to the system of bodily processes that help to maintain our core temperature. Efficient thermoregulation is linked to better athletic performance and sweat is one mechanism that the body uses to cool off when its core temperature becomes too high. But trying for more sweat using salt, thinking that will keep you cooler, is bordering on sports homeopathy.
To determine the effects of high-dose sodium supplementation on thermoregulation and related measures, 11 endurance athletes participated in a double-blind study in which they underwent two hours of endurance exercise at 60 percent heart rate reserve (the difference between maximum heart rate and resting heart rate) followed by an exercise performance test. The exercise resulted in more than two liters of water loss in the form of sweat. During one session, the athletes received 1800 mg of sodium supplementation and during the other, they received a placebo.
Weiss and fellow researchers Elizabeth Earhart, Rabia Rahman, and Patrick Kelly found that sodium supplementation did not appear to impact thermoregulation. The investigators calculated sweat rate, perceived exertion, heat stress, cardiovascular drift (increased heart rate after a period of exercise even when exertion remains constant), skin temperature and dehydration. None of the measures showed significant statistical difference between trials.
When these findings are considered together with the known health concerns associated with too much salt consumption, Weiss urges a conservative interpretation of guidelines calling for sodium replenishment for athletes.
"While moderate sodium consumption is perfectly reasonable and should be encouraged, high sodium intake is associated with health concerns, like hypertension," Weiss said. "Many Americans already consume too much salt on a daily basis. I recommend that athletes use caution with sodium supplementation, especially when daily intakes already exceeds the upper safe limit of 2300 mg/day for most Americans."
Top image: Mid Pacific University