Maughan R J
J Sports Sci. 1986 Spring;4(1):31-4. doi: 10.1080/02640418608732095.
Exercise-induced muscle cramp has been considered to result from disturbances of fluid and electrolyte balance resulting from excessive sweat loss. Serum biochemical and haematological measurements were made on 82 male marathon runners before and after a 42.2-km race. Fifteen (18%) of the runners reported an attack of muscle cramp which occurred after 35 +/- 6 km (mean +/- S.D.) had been covered. These subjects were not different from the others in terms of racing performance or training status. Serum electrolyte concentrations, including sodium and potassium, were not different between those suffering from cramp and those not so affected either before or after the race, although a significant (P less than 0.001) increase in serum sodium concentrations occurred in both groups. Serum bicarbonate concentrations fell to the same extent (from 28 to 24 mmol l-1) in both groups. Significant decreases in plasma volume, calculated from the changes in circulating haemoglobin and haematocrit, occurred in both groups of subjects, but there was no difference in the extent of the haemoconcentration. The results suggest that exercise-induced muscle cramp may not be associated with gross disturbances of fluid and electrolyte balance.
运动诱发的肌肉痉挛被认为是由过度出汗导致的体液和电解质平衡紊乱引起的。对82名男性马拉松运动员在42.2公里比赛前后进行了血清生化和血液学测量。15名（18%）运动员报告在跑了35±6公里（平均±标准差）后出现肌肉痉挛发作。这些受试者在比赛成绩或训练状态方面与其他运动员没有差异。血清电解质浓度，包括钠和钾，在痉挛者和未受影响者之间在比赛前后均无差异，尽管两组血清钠浓度均有显著（P<0.001）升高。两组血清碳酸氢盐浓度下降幅度相同（从28降至24 mmol/L）。根据循环血红蛋白和血细胞比容的变化计算，两组受试者的血浆量均显著减少，但血液浓缩程度没有差异。结果表明，运动诱发的肌肉痉挛可能与体液和电解质平衡的严重紊乱无关。
