The Truth About Endurance Athletes and Salt
No, athletes aren't OD'ing on salt pills. But here's when you should lay off of them.
Been popping salt pills like M&Ms during long workouts thinking they’ll do your body good? You might want to think again: According to St. Louis University nutrition and dietetics professor, Dr. Ted Weiss, extra sodium from concentrated sources like salt capsules doesn’t actually enhance athletic performance. In fact, downing the pills may even cause hypertension.
“A lot of sports nutrition practices directly contradict what we know about positive health practices,” Weiss says. “Just because something makes you run faster doesn’t mean it’s healthy. Cocaine does that too, but that doesn't mean it's good for you.”
For years, the FDA has recommended Americans take in no more than 2,300 milligrams of sodium per day. But endurance athletes can easily exceed that amount when they gulp electrolyte capsules during exercise—some pills are stuffed with more than 200 milligrams of sodium each.
“A lot of people think salt is critical for performance, but there’s really not any convincing evidence of that,” Weiss says. Though the pills are advertised to help minimize cramps, heat stress, and fatigue, many studies have found there’s not much of a link between these issues and salt intake. In fact, a recent study Weiss and his colleagues published in the Journal of Sports Science and Medicine found salt supplementation had no effect on performance during a moderate two-hour run.
“Just because something makes you run faster doesn’t mean it’s healthy,” Ted Weiss says. “Cocaine does that. But you don’t see cocaine at aid stations.”
For this study, athletes consumed about half the amount of salt they’d lost through sweat, or 900 milligrams per hour. That salt intake, the researchers concluded, “did not have a significant effect on sweat rate…heat stress, skin temperature, rating of perceived exertion, or time to exhaustion in trained endurance athletes.”
Even athletes participating in ultra-distance events should reconsider the use of salt pills explains Dr. Martin Hoffman, Research Director of the Western States Endurance Run, who's found that supplemental sodium isn't necessary, even at that grueling 100 mile distance. “It won’t prevent hyponatremia, muscle cramps or GI symptoms,” he wrote in an email. “It will help runners maintain a higher body weight, but excessive sodium intake may also promote overhydration, and actually be a risk for development of exercise-associated hyponatremia.”
That’s not to say athletes don’t need salt. “The general consensus from sports nutrition is that there’s probably a somewhat higher need for salt in endurance athletes than in the general population,” Weiss says. But most athletes are getting more than enough salt through their normal diets “just by virtue of eating more food to fuel their exercise.” Someone training for a marathon, for instance, may eat two sandwiches instead of one for lunch, or twice as many calories as a sedentary person. On top of that, the 2,300 milligram per day limit is generous, Weiss says. The general population should be getting closer to 1,500 milligrams per day. In other words, if you’re getting in 2,300 milligrams per day, you’re already getting more than the general population needs.
Yes, the threat of hyponatremia, or low blood sodium, is real. But Weiss argues that it’s a minor issue for most people, while the chance of over salting—and the associated side effects of high blood pressure and cardiovascular disease—is much greater.
If you’re a salt supplementer, Weiss recommends reducing your intake and seeing if you notice any adverse effects. “Keep it under 2,300 milligrams a day,” he says. “If you feel like you need more, use it cautiously, and only when the workouts are long and hard and hot.”