Resumo

BECKER, Geórgia Franco; FLORES, Liziane Maahs; SCHNEIDER, Cláudia Dornelles  e  LAITANO, Orlando. Perda de eletrólitos durante uma competição de duatlo terrestre no calor. Rev. Bras. Educ. Fís. Esporte [online]. 2011, vol.25, n.02, pp.215-223. ISSN 1981-4690.

Prolonged sports events such as duathlon (6 km running, 26 km cycling and 4 km running), may lead the athlete to a fluid and electrolyte imbalance, due to high sweat rates, especially in a hot environment. The present study evaluated sodium (Na⁺), potassium (K⁺) and chloride (Cl^-) losses during a duathlon competition performed in the heat (31,2 °C and 51% relative humidity), analyzing the sweat composition and blood levels of these electrolytes. Twelve athletes took part in this study. Blood samples were obtained pre- and post-exercise and sweat was collected using sweat patches. The average time to complete the competition was 85.0 ± 6.57 min. The percentage of dehydration was 3.0 ± 0.92%. The replacement of fluid losses was 31 ± 18.7%. The sweat rate was 1.86 ± 0.56 L•h^-1. Sweat Na⁺, K⁺, and Cl^- concentrations were 71 ± 26.05 mmol•L^-1, 5.43 ±1.98 mmol•L^-1 and 58.93 ± 25.99 mmol•L^-1, respectively. The total sweat loss of Na⁺, K⁺ and Cl^- was 132.11± 62.82 mmol, 10.09 ± 5.01 mmol and 109.75 ± 58.49 mmol, respectively. In conclusion, the athletes did not drink enough liquid to replace their volume of fluid loss. Furthermore, the participants presented high sweat rate accompanied by losses of Na⁺, K⁺ and Cl^-. However, serum electrolyte concentrations were not changed.

Palavras-chave : Exercise; Dehydration; Sweat; Temperature.

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