Myth #4: Guzzling water prevents cramps

Truth: Water and electrolytes have little to do with muscles seizing up

Water and electrolytes have little to do with muscles seizing up.

Water and electrolytes have little to do with muscles seizing up.     Photo: Inga Hendrickson

For years we’ve heard that exercise-­induced cramping is caused by dehydration and the associated loss of sodium and ­potassium. We’ve been urged to load up on ­bananas or chug salty sports drinks before and during workouts. But in 2011, South African researchers studied hundreds of Ironman triathletes, a group frequently felled by muscle cramps. To check for signs of clinical dehydration, researchers took blood samples just prior to the event’s start, for measuring levels of sodium and other electrolytes, then drew blood again at the finish line. Forty-three of the Ironmen cramped during the race, but the afflicted were no more dehydrated than the other competitors were, and they had comparable electrolyte levels. The principal difference between the two groups was speed: the tested group finished faster.

A team of scientists at North Dakota State University in Fargo reached similar conclusions. In a 2010 study, the researchers asked a group of fit young men to fill up with ­water, then induced cramping by zapping them with a series of low-level electric pulses. They did the same after the men rode stationary bikes in a heat chamber, with some of them losing up to 3 percent of their body weight to sweat. Since it took the same number of electrical shocks to induce cramping again, the spasms “were likely not caused by dehydration,” says professor Kevin Miller, who led the study. Instead, he believes that muscle cramps are due to exertion, fatigue, and a cascade of accompanying biochemical processes.

Get over it: Miller can’t tell you how to eliminate cramps altogether—there isn’t enough research—but stretching seems to be the best option to relieve acute cramping once it’s set in. That and pickle juice. In one of Miller’s recent studies, cramp-stricken ­cyclists who drank 2.5 ounces of it recovered 45 percent faster than those who drank nothing. Miller speculates that something in the acidic juice disrupts the nervous-system ­melee in the exhausted muscle.

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