The other night I woke suddenly from sleep with an intense cramp in my right thigh. This was not the first time that I had experienced such a cramp. As always, it seemed perplexing to me that I would have a cramp in the middle of the night. I exercise routinely but drink plenty of fluids while biking or hiking. I have never had problems with my electrolytes and I eat a reasonably well-balanced diet. And, it seemed odd that the cramp occurred so many hours after exercising. Similar to the situation with the hiccup, what causes cramps is not well known.
For years, sports medicine experts have theorized that cramps are the result of muscle dehydration or small muscle tears. The treatment of choice is a balanced fluid-electrolyte solution. However, I have seen many of my children’s teammates suffer from cramps during soccer games despite drinking tremendous amounts of fluids before playing and at half-time. As reported in The Wall Street Journal, it turns out that the experts focus on fluid balance and the muscle may have been completely wrong. The problem may not be with the muscle at all but actually with the nerve that innervates the muscle. Scientists hypothesized that nerves were sending signals to muscles leading them to misfire and the development of cramps.
If that were the case, the best approach to preventing cramps would be to prevent unwarranted firing of motor neurons. One could directly suppress motor impulses but that certainly would impede exercise performance. However, if the overall sensory input perceived by the nervous system could be safely augmented, that might lead to an overall damping effect on excessive motor output. To test this theory, adult volunteers ingested various amounts of spicy foods-which trigger receptors in the mouth and esophagus, and then scientists attempted to induce muscle cramps with electrical impulses. The results confirmed that it was harder to induce muscle cramps in adults who had ingested spicy foods.
Randomized trials established that subjects who consumed spicy foods before exercise reported fewer cramps than those that had not consumed spicy foods. Interestingly, for years some athletes had been drinking fairly spicy fluids such as pickle or beet juice to help prevent muscle cramps. While the claim was that these fluids improved blood flow to muscles, they in fact do not. However, perhaps because of sensory overload of gastrointestinal tract receptors, the athletes were less inclined to develop muscle cramps. As for me, I think the next time I go out for a hard bike ride I will forgo the banana and eat a snack made with some hot, Thai chili peppers.