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Agreed but the point was about cramping, not bonking.

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Unfortunately, there's not a lot of medical evidence as to what makes us cramp, and what makes cramps better. Clearly, fluid, sodium, potassium, calcium, and magnesium play some part, so replacing most or all of these empirically does help. Magnesium is known to relax muscle but it has only been studied in depth in extreme conditions not really applicable to us as cramping cyclists. By this I mean things like premature labor (uterine "cramping"), tetany, and cardiac arrest. Hopefully none of these applied to the OP

So, if you're bonking, or cramping, it will likely help to take sports drink.