Sweat sodium composition and sweat loss estimation through wearable sensors and predictive equations in dry and humid hot conditions

S1 offers equivalent and more practical collection of sweat [Na⁺] compared to the LAQUAtwin during indoor cycling ergometer exercise. However, measurements from both devices should currently be interpreted with caution and not considered equivalent to laboratory-grade analyses. Furthermore, S1 is an adequate tool during indoor cycling ergometer exercise to estimate WBSL when scale measurements are impractical, while SRC was found to underestimate fluid loss.