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Table 2 Sweat and performance variables according to sweat electrolyte concentration. Data is mean ± SD for each group

From: Interindividual variability in sweat electrolyte concentration in marathoners

Variable (units) Low-salt sweat Typical Sweat Salty sweat P value
<30 mmol·L−1 [sweat Na+] 30–60 mmol·L−1 [sweat Na+] >60 mmol·L−1 [sweat Na+]
Number/Frequency 42/27 % 84/54 % 31/20 % -
Men/women 37/5 73/11 31/0 0.11
Sweat Na+ concentration (mmol·l−1) 21.4 ± 6.4* 43.2 ± 8.8 71.0 ± 9.0*† <0.01
Sweat Cl concentration (mmol·l−1) 16.4 ± 4.3* 31.9 ± 9.9 54.4 ± 10.7*† <0.01
Sweat K+ concentration (mmol·l−1) 5.9 ± 0.9 5.9 ± 0.9 6.2 ± 0.6 0.26
Sweat osmolality (mOsm·kg H2O−1) 100.8 ± 38.9* 150.4 ± 42.1 206.3 ± 40.3*† <0.01
Sweat rate (L·h−1) 0.9 ± 0.2 0.9 ± 0.3 1.0 ± 0.2 0.76
Sweat NaCl loss (g L−1) 1.1 ± 0.3* 2.1 ± 0.5 3.5 ± 0.6*† <0.01
Fluid intake (L·h−1) 0.32 ± 0.18 0.31 ± 0.17 0.33 ± 0.15 0.85
Na+ intake (mmol) 12.3 ± 8.1 11.9 ± 9.9 14.6 ± 16.6 0.81
Cl intake (mmol) 21.3 ± 13.0 20.8 ± 15.0 24.0 ± 25.0 0.72
K+ intake (mmol) 5.1 ± 6.0 4.7 ± 7.9 6.0 ± 5.6 0.85
Running pace (m·s−1) 3.0 ± 0.4 3.1 ± 0.5 3.2 ± 0.5 0.18
Average training distance·week−1 (km) 65.1 ± 32.0 60.5 ± 26.7 64.2 ± 24.1 0.65
  1. P values correspond to Chi square tests -used to identify differences for the ratio men/women- and ANOVA tests -used to establish among-groups differences for the remaining variables-. (*) Different from typical sweat at P < 0.05; (†) Different from low-salt sweat at P < 0.05