Low Sweat Production Linked to Exercise-Induced Asthma
Patients with positive methacholine challenge testing may also have diminished sweat production
WEDNESDAY, Sept. 10 (HealthDay News) -- Decreased sweat secretion rates are associated with positive response to methacholine challenge testing among patients with suspected exercise-induced asthma, according to a report in the September issue of Chest.
Chan Park, M.D., of Naval Medical Center in San Diego, and colleagues recruited 56 healthy subjects with suspected exercise-induced bronchospasm to undergo provocative methacholine challenge tests and measurements of pilocarpine-induced sweat secretion. The researchers investigated whether humans responded similarly to a mouse model demonstrating that excessive bronchiolar reactivity leads to a decline in muscarinic receptor-dependent sweat gland secretion. A subset of patients also underwent measurement of oral secretions and lachrymal tearing.
Overall, 22 subjects had a positive methacholine challenge test (a 20 percent decline in FEV1 compared to baseline) and 34 subjects had a minimal or negative challenge, the investigators found. Patients demonstrating excessive airway reactivity to methacholine challenge testing also had significantly reduced pilocarpine-induced sweat secretion. Pilocarpine-stimulated sweat secretion was significantly correlated with salivary flow rate and tearing rate, the report indicates.
"Hyperhidrosis, sialorrhea and excessive tearing are traits that may indicate a phenotype that predicts resistance to hyperactive airway diseases such as exercise-induced asthma in humans," the authors conclude.