Attenuated salivary cortisol response after exercise test in children with asthma

Objective: The clinical relevance of lower basal cortisol levels in children with asthma is unclear. We compared the salivary cortisol response after a standardized exercise test in children with asthma versus the salivary cortisol response in healthy children.Methods: Nineteen prepubertal children with asthma and 20 prepubertal healthy children performed a standardized exercise test twice. Salivary cortisol levels were determined before exercise and immediately and 15 min after exercise. Morning salivary cortisol levels were determined from saliva collected at home.Results: Salivary cortisol levels increased in 84.2% of the healthy children compared to 35.0% in children with asthma after the 20-m shuttle-run test. Median increase in salivary cortisol levels was 200.3% [95% confidence interval (CI), 141.8-346.1] in healthy children compared to 89.8% (95% CI, 56.9-181.6) in children with asthma. The response was not related to the morning salivary cortisol level or maintenance dose of inhaled corticosteroids. The mean time to exhaustion of both shuttle-run tests was significantly shorter in children with asthma (mean difference 1.4 min; 95% CI, 0.7-2.3). None of the children had to stop because of dyspnea.Conclusion: Our study demonstrates that children with asthma using a maintenance dose of inhaled corticosteroids (ICS) have an attenuated salivary cortisol response compared with healthy children.