Add cramp prevention to the list of hydration myths: if your muscles seize up while you're exercising, it's not because you're dehydrated.
Photo by Roberto Ferrari.
Caleb Maslund at Daily Mile explains a few of the studies that have put this myth to rest, like this one from BMJ Sports Medicine that found no difference in hydration status or electrolytes (measured by blood samples) in runners that did and did not cramp up in a 35-mile "ultramarathon" race. Based on this and other studies, scientists currently believe that exercise cramps come from a miscommunication between the brain and muscles, brought on by fatigue. Hydration, with or without electrolytes, won't prevent or cure cramps.
To add to your disappointment, Kevin Miller at MomsTeam debunks some of the popular cramp cures: bananas don't work, although pickle juice might (but not because of electrolytes; it makes cramps subside long before any of the salt has been absorbed into your bloodstream).
What does work? Training more so your muscles don't get fatigued as easily, and in a pinch, activating the muscle opposite the cramping one. (This is sometimes referred to as "stretching," but it works even if you don't lengthen the cramping muscle enough to stretch it.) Read the rest at Daily Mile for more on what to do about race-day cramps.
Race Cramping: Causes and Prevention [Daily Mile]