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