Effects of Combined Training on Cardiac Autonomic Modulation in Asthmatic Adolescents

Exercise-induced bronchoconstriction (EIB) is defined as the acute narrowing of the lower respiratory airways after exercise. This study aimed to verify the behavior of cardiac autonomic modulation after combined training in asthmatic adolescents with and without EIB.

This is a clinical study in which 16 asthmatic adolescents (10 with EIB and 6 without EIB) performed combined exercise (aerobic and resistance) for 12 weeks with a frequency of 3 sessions per week. The diagnosis of EIB was established based on a > 10% reduction in forced expiratory volume in 1 s (FEV₁) from baseline, measured at 5, 10, 15, and 30 min after a treadmill bronchoprovocation test. Heart rate variability (HRV) was recorded at rest and 40 min after the bronchoprovocation test. Both assessments were performed before and after the concurrent training program. Generalized equation estimation (GEE) was performed to evaluate the interaction between the groups at the evaluated times.

There was sympathetic impairment (mean RR interval and heart rate) in patients with and without EIB after the bronchoprovocation test in the 40 min evaluated, which improved after combined training at all times evaluated in patients without EIB and after 10 min in those with EIB (p < 0.001). The parasympathetic component (percentage of adjacent intervals over 50 ms[PNN50]) was not altered after the bronchoprovocation test in individuals without EIB before and after training. In individuals with EIB, pNN50 was changed 40 min after the bronchoprovocation test before training and showed improvement after 10 min (p < 0.001) in the reassessment.

An improvement in autonomic response was observed in asthmatic adolescents without EIB following combined physical training, evident from the first minute post-bronchoprovocation test, whereas in those with EIB, this improvement became apparent after 10 min.