马拉松运动员汗液电解质浓度的个体间差异。
Interindividual variability in sweat electrolyte concentration in marathoners.
作者信息
Lara Beatriz, Gallo-Salazar César, Puente Carlos, Areces Francisco, Salinero Juan José, Del Coso Juan
机构信息
Camilo José Cela University Exercise Physiology Laboratory, C/ Castillo de Alarcon, 49, Villafranca del Castillo, 28692 Spain.
出版信息
J Int Soc Sports Nutr. 2016 Jul 29;13:31. doi: 10.1186/s12970-016-0141-z. eCollection 2016.
BACKGROUND
Sodium (Na(+)) intake during exercise aims to replace the Na(+) lost by sweat to avoid electrolyte imbalances, especially in endurance disciplines. However, Na(+) needs can be very different among individuals because of the great inter-individual variability in sweat electrolyte concentration. The aim of this investigation was to determine sweat electrolyte concentration in a large group of marathoners.
METHODS
A total of 157 experienced runners (141 men and 16 women) completed a marathon race (24.4 ± 3.6 °C and 27.7 ± 4.8 % of humidity). During the race, sweat samples were collected by using sweat patches placed on the runners' forearms. Sweat electrolyte concentration was measured by using photoelectric flame photometry.
RESULTS
As a group, sweat Na(+) concentration was 42.9 ± 18.7 mmol·L(-1) (minimal-maximal value = 7.0-95.5 mmol·L(-1)), sweat Cl(-) concentration was 32.2 ± 15.6 mmol·L(-1) (7.3-90.6 mmol·L(-1)) and sweat K(+) concentration was 6.0 ± 0.9 mmol·L(-1) (3.1-8.0 mmol·L(-1)). Women presented lower sweat Na(+) (33.9 ± 12.1 vs 44.0 ± 19.1 mmol·L(-1); P = 0.04) and sweat Cl(-) concentrations (22.9 ± 10.5 vs 33.2 ± 15.8 mmol·L(-1); P = 0.01) than men. A 20 % of individuals presented a sweat Na(+) concentration higher than 60 mmol·L(-1) while this threshold was not surpassed by any female marathoner. Sweat electrolyte concentration did not correlate to sweat rate, age, body characteristics, experience or training. Although there was a significant correlation between sweat Na(+) concentration and running pace (r = 0.18; P = 0.03), this association was weak to interpret that sweat Na(+) concentration increased with running pace.
CONCLUSIONS
The inter-individual variability in sweat electrolyte concentration was not explained by any individual characteristics except for individual running pace and sex. An important portion (20 %) of marathoners might need special sodium intake recommendations due to their high sweat salt losses.
背景
运动期间摄入钠（Na⁺）旨在补充因出汗而流失的Na⁺，以避免电解质失衡，尤其是在耐力项目中。然而，由于个体汗液电解质浓度存在很大差异，个体对Na⁺的需求可能有很大不同。本研究的目的是测定一大群马拉松运动员的汗液电解质浓度。
方法
共有157名经验丰富的跑步者（141名男性和16名女性）完成了一场马拉松比赛（温度24.4±3.6°C，湿度27.7±4.8%）。在比赛过程中，使用贴在跑步者前臂上的汗液贴片收集汗液样本。采用光电火焰光度法测量汗液电解质浓度。
结果
总体而言，汗液Na⁺浓度为42.9±18.7 mmol·L⁻¹（最小值 - 最大值 = 7.0 - 95.5 mmol·L⁻¹），汗液Cl⁻浓度为32.2±15.6 mmol·L⁻¹（7.3 - 90.6 mmol·L⁻¹），汗液K⁺浓度为6.0±0.9 mmol·L⁻¹（3.1 - 8.0 mmol·L⁻¹）。女性的汗液Na⁺浓度（33.9±12.1 vs 44.0±19.1 mmol·L⁻¹；P = 0.04）和汗液Cl⁻浓度（22.9±10.5 vs 33.2±15.8 mmol·L⁻¹；P = 0.01）低于男性。20%的个体汗液Na⁺浓度高于60 mmol·L⁻¹，而没有任何女性马拉松运动员超过这一阈值。汗液电解质浓度与出汗率、年龄、身体特征、经验或训练无关。虽然汗液Na⁺浓度与跑步速度之间存在显著相关性（r = 0.18；P = 0.03），但这种关联较弱，难以说明汗液Na⁺浓度随跑步速度增加。
结论
除了个体跑步速度和性别外，个体特征无法解释汗液电解质浓度的个体差异。由于汗液盐分流失量大，相当一部分（20%）马拉松运动员可能需要特殊的钠摄入建议。
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