Sweat electrolyte loss in asthmatic children during exercise in the heat.

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 cycleergometer test. During a second session, participants cycled in the heat (35 degrees 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.