Rationale: Although exercise-induced bronchoconstriction is more common in adolescents with asthma, it also manifests in healthy individuals without asthma. The steady-state exercise protocol is widely used and recommended by the American Thoracic Society (ATS) as a method to diagnose exercise-induced bronchoconstriction. Airway narrowing in response to exercise is thought to be related to airway wall dehydration secondary to hyperventilation. More rigorous exercise protocols may have a role in detecting exercise-induced bronchoconstriction in those who otherwise have a normal response to steady-state exercise challenge.Objectives: The objective of this study was to determine the effect of two different exercise protocols-a constant work rate protocol and a progressive ramp protocol-on pulmonary function testing in healthy adolescents. We hypothesized that vigorous exercise protocols would lead to reductions in lung function in healthy adolescents.Methods: A total of 56 healthy adolescents (mean age, 15.2 6 3.3 [SD] years) were recruited to perform two exercise protocols: constant work rate exercise test to evaluate for exercise-induced bronchoconstriction (as defined by ATS) and standardized progressive ramp protocol. Pulmonary function abnormalities were defined as a decline from baseline in FEV 1 of greater than 10%.Measurements and Main Results: Ten participants (17.8%) had a significant drop in FEV 1 . Among those with abnormal lung function after exercise, three (30%) were after the ATS test only, five (50%) were after the ramp test only, and two (20%) were after both ATS and ramp tests.Conclusion: Healthy adolescents demonstrate subtle bronchoconstriction after exercise. This exercise-induced bronchoconstriction may be detected in healthy adolescents via constant work rate or the progressive ramp protocol. In a clinical setting, ramp testing warrants consideration in adolescents suspected of having exercise-induced bronchoconstriction and who have normal responses to steady-state exercise testing.

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Brief exercise results in substantial changes in gene expression of circulating PBMCs. Moreover, many key gene pathways influenced by exercise are related to inflammation. We hypothesized that microRNAs (small 21–23 nucleotide non‐coding RNAs) would also be changed by exercise and act to prevent a predominantly pro‐inflammatory PBMC response that could be dangerous. 12 healthy men (19–30 y.o.) performed 20 min of cycle ergometry (~75% peak VO2). PBMCs were isolated before and after the exercise. Using the Agilent Human miRNA Microarray (V2), we found that exercise altered 94 miRNAs (FDR=0.2; 61 downregulated). Many of the miRNAs altered by exercise are known to play mechanistic roles in other inflammatory processes [e.g., miR‐125b(↓) and miR‐146a(↓) which are downregulated by proinflammatory factors LPS and TNF‐α, respectively). We also found exercise effects on miRNAs associated with B‐cell development, e.g., miR‐181a(↑), ‐150(↓), and ‐17(↓). Further, we compared the miRNA changes in PBMCs with the 38 miRNAs in neutrophils that we previously found to have been altered by exercise. 18 miRNAs were affected in both PBMCs and neutrophils, but only 12 changed in the same direction. In conclusion, brief heavy exercise changes miRNA profiles in PBMCs many of which are related to inflammatory processes. The pattern of change suggests that exercise differentially influences miRNAs in leukocyte subtypes. Grants: Supported by NIH grants P01‐HD048721 and RO1‐HL080947

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