School of Sports Medicine, University of Verona, Policlinico GB Rossi, 37134 Verona, Italy.
Clin J Sport Med. 2010 Jan;20(1):47-52. doi: 10.1097/JSM.0b013e3181c9673f.
To investigate the drinking behavior of the participants in a multi-day mountain bike (MTB) cross-country competition, to monitor its effect on the body's fluid compartments and body mass, and to evaluate the prevalence of exercise-associated dysnatremia.
Descriptive field study.
The Jeantex Bike Transalp Competition 2008 (8 stages; 665.40 km; 21 691 m height).
Twenty-five male, amateur MTB cyclists.
Reported fluid intake during the race, air temperature.
Changes in body mass and body composition from pre to post race and throughout the competition week, serum sodium concentration at finish line of stages 5 and 6.
Mean (+ or - SD) hourly fluid intake during the race correlated with air temperature (r = 0.868, P < .05) and ranged between 494 + or - 191 mL/h and 754 + or - 254 mL/h. In absence of exercise-induced hyponatremia (EAH) cases, we report 5 and 4 cases of asymptomatic post-race hypernatremia, on days 5 and 6, respectively. When related to race time and body mass, the liquid intake during the race (in mL x kg(-1) x h(-1)) correlated with post-race serum sodium concentration (stage 5: r = -0.463, P < .05, n = 24; stage 6: r = -0.589, P < .01, n = 23); no correlation was found between the change in body mass from pre to post race and serum sodium concentration at finish line.
Ad libitum fluid consumption during competition was spontaneously adjusted to the unsettled weather conditions in the course of the 2008 "Bike Transalp." The inverse linear relationship between hourly fluid intake and post-race serum sodium concentrations suggests underdrinking to be one contributing factor to the high reported incidence of hypernatremia in the absence of EAH. Experimental studies are requested to confirm this hypothesis and to further examine the pathogenesis of exercise-associated dysnatremia. In this setting, body mass monitoring was not an accurate instrument to control body fluid homeostasis.
调查参加多日山地自行车（MTB）越野比赛的参与者的饮酒行为，监测其对身体液体隔间和体重的影响，并评估运动相关的电解质紊乱的发生率。
描述性实地研究。
2008 年 Jeantex Bike Transalp 比赛（8 个阶段；665.40 公里；21691 米高度）。
25 名男性业余 MTB 自行车手。
比赛期间报告的液体摄入量、空气温度。
比赛前后和整个比赛周的体重和身体成分变化，第 5 和第 6 阶段终点线的血清钠浓度。
比赛期间每小时平均（+或-标准差）液体摄入量与空气温度相关（r = 0.868，P <.05），范围在 494 +或-191 毫升/小时和 754 +或-254 毫升/小时之间。在没有运动引起的低钠血症（EAH）病例的情况下，我们分别在第 5 天和第 6 天报告了 5 例和 4 例无症状赛后高钠血症。当与比赛时间和体重相关时，比赛期间的液体摄入量（以毫升 x 千克（-1）x 小时（-1）表示）与赛后血清钠浓度相关（第 5 阶段：r = -0.463，P <.05，n = 24；第 6 阶段：r = -0.589，P <.01，n = 23）；比赛前后体重变化与终点线血清钠浓度之间无相关性。
在 2008 年“Bike Transalp”比赛中，比赛期间自由饮水会根据比赛过程中不稳定的天气条件自动调整。每小时液体摄入量与赛后血清钠浓度之间的线性反比关系表明，低摄入量是导致在没有 EAH 的情况下高报告高钠血症发生率的一个因素。需要进行实验研究来证实这一假设，并进一步研究运动相关电解质紊乱的发病机制。在这种情况下，体重监测不是控制体液平衡的准确仪器。
