Regional variations in sweat sodium, chloride and potassium concentrations. Data were obtained from 13 papers that reported both electrolyte concentrations and sweat rates, or information that permitted derivation of the latter. These sweat rate ranges and sample sizes for each site are provided in Table5. Data are means with 95% confidence intervals across studies. Site-specific sweat compositions were computed as follows: regional composition = ((N1 × X1) + (N2 × X2) + … (Ni × Xi)) ∕ NTotal (where N is the sample size, X is the electrolyte composition and subscript numerals refer to separate studies). Sources: Sato et al., Patterson et al., Allan and Wilson, van den Heuvel et al., Yousef and Dill, Hayden et al., Collins, Locke et al., Emrich et al., Costa et al., Cage et al., Boisvert et al., Fukumoto et al. and Saat et al..