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There are a dizzying array of drinks and powders on the market that promise to keep you hydrated and boost energy levels. A lot of them promise to flood your body with the seemingly-magical, heal-all properties of electrolytes. But what are electrolytes really – and how can you tell if you’re getting enough?
What Are Electrolytes and Why Does the Body Need Them?
Every bead of sweat that drips from your face contains a mixture of electrolytes — in layman’s terms, “positively or negatively charged ions that conduct electrical activity,” says Jonathan Toker, Ph.D., an organic chemist and elite trail runner who founded the hydration-products company SaltStick. “They are necessary to help maintain proper fluid balance, [and] perform functions involved in muscle contraction and relaxation.”
When electrolyte levels drop too low, the body’s performance can suffer. Signs of this include muscular fatigue, cramping, poor thermoregulation that makes heat less tolerable, and feelings of disorientation. In extreme cases, consuming a large volume of water without sufficient electrolytes can lead to dangerously low levels of sodium in the blood, a potentially life-threatening condition known as hyponatremia.
And while there are plenty of reasons you might be short on electrolytes, a big one is sweat. On the dance floor, soccer field, or during a hot run, every drop of sweat is taking precious electrolytes with it.
“The electrolytes lost in the highest concentrations through sweat are sodium and chloride,” says Maria Dalzot, a sports dietitian and competitive mountain runner based in Bellingham, Washington. “These electrolytes must be tightly regulated for the body to function properly.” Potassium, magnesium and calcium are also lost in sweat, though “in such small amounts that they are not of concern while exercising and can be easily replaced in your everyday diet.”
Some (though not all) experts say that replenishing those lesser electrolytes becomes vital during sustained, multi-hour efforts.“With a finite amount available in the body for easy access, cumulative losses over time for an athlete running four, six, or 17 hours will affect calcium and magnesium levels in the blood and inhibit performance,” Toker says. But if you’re out for a leisurely run lasting less than an hour, your electrolyte stores should be adequate without supplementation. “Replacing salt losses becomes more of a concern when you push past the 60-minute mark, particularly if you’re sweating greatly,” he adds.
Sweat production, and therefore electrolyte loss, is influenced by a number of factors, including run duration and intensity, genetics, clothing and environmental conditions like humidity. “A less fit runner will lose more electrolytes compared to an avid runner who is more efficient at maintaining electrolyte homeostasis,” says Dalzot. What’s more, some people’s sweat is naturally saltier.
According to Toker, the sweet spot for most athletes is to replenish between 50 and 80 percent of electrolytes lost during exercise. “Higher replacement usually causes stomach issues, and lower replacement usually causes performance deterioration,” he says.
Are Sports Drinks the Best Way to Get Electrolytes?
Most of those neon-colored drinks contain no more than 200 milligrams of sodium, which doesn’t come close to matching what endurance athletes lose through their sweat glands. If you’re recovering from something more strenuous than a big night out, look to other sources, including salt capsules, electrolyte tablets, and dissolvable powders and enhanced gels and chews.
But do be mindful about your intake. “If you do choose to take salt tablets, be sure to drink a sufficient amount of water,” warns Dalzot. “A large intake of sodium without water can cause bloating as water moves from the bloodstream to dilute the sodium concentration. Sodium also triggers thirst and drinking more than necessary can cause unpleasant stomach sloshing.”
Don’t forget that “real” food can be a good source of sodium as well. If you just finished sweating buckets on a multi-hour epic, you might want to reach for those salty, crunchy snacks you’re craving, like pretzels, nuts, potato chips.
This article originally appeared in the July 2015 issue of Trail Runner Magazine.