This study assessed sweat electrolyte concentration and losses in asthmatic children during exercise in the heat. Eleven asthmatics (AG; 11 ± 2 years old) and 11 nonasthmatics (CG; 10 ± 1 year old) underwent a maximal progressive cycle-ergometer test. During a second session, participants cycled in the heat (35°C, 60% RH) of a climatic chamber for 30 min at 50–60% of maximal workload. Sweat was collected using sweat patches attached to the dorsal region. No differences were observed in sweat [Na+] (AG = 35 ± 12.9 and CG = 43.4 ± 18 mmol/L) and [Cl-] (AG = 27.3 ± 10.4 and CG = 38.5 ± 19.1 mmol/L). There was no difference in sweat Na+ losses (AG = 0.47 ± 0.36 and CG = 0.66 ± 0.68 mmol/kg/h) and Cl- losses (AG = 0.37 ± 0.29 and CG = 0.59 ± 0.62 mmol/kg/h) between groups. Asthmatic children did not differ from nonasthmatics in their sweat electrolyte concentrations and electrolyte losses.
Laitano, Martins, Perrone, and Meyer are with Universidade Federal do Rio Grande do Sul – Escola de Educação Física – Laboratório de Pesquisa do Exercício – Programa de Pós-graduação em Ciências do Movimento Humano, Porto Alegre, Brazil. Mattiello and Fischer are with Hospital da Criança Santo Antônio – Fundação Faculdade de Ciências Médicas, Porto Alegre, Brazil.