Interindividual variability in sweat electrolyte concentration in marathoners.

摘要: Sodium (Na+) intake during exercise aims to replace the Na+ lost by sweat avoid electrolyte imbalances, especially in endurance disciplines. However, needs can be very different among individuals because of great inter-individual variability concentration. The aim this investigation was determine concentration a large group marathoners. A total 157 experienced runners (141 men and 16 women) completed marathon race (24.4 ± 3.6 °C 27.7 ± 4.8 % humidity). During race, samples were collected using patches placed on runners’ forearms. Sweat measured photoelectric flame photometry. As group, 42.9 ± 18.7 mmol·L−1 (minimal-maximal value = 7.0–95.5 mmol·L−1), Cl− 32.2 ± 15.6 mmol·L−1 (7.3–90.6 mmol·L−1) K+ 6.0 ± 0.9 mmol·L−1 (3.1–8.0 mmol·L−1). Women presented lower (33.9 ± 12.1 vs 44.0 ± 19.1 mmol·L−1; P = 0.04) concentrations (22.9 ± 10.5 33.2 ± 15.8 mmol·L−1; P = 0.01) than men. 20 % higher 60 mmol·L−1 while threshold not surpassed any female marathoner. did correlate rate, age, body characteristics, experience or training. Although there significant correlation between running pace (r = 0.18; P = 0.03), association weak interpret that increased with pace. explained individual characteristics except for sex. An important portion (20 %) marathoners might need special sodium recommendations due their high salt losses.