Introduction: The autonomic nervous system plays an important role in regulating airway caliber and although exercise is a triggering factor for bronchial hyperresponsiveness, there is a lack of scientific evidence on autonomic modulation in young asthmatics with exercise-induced bronchospasm (EIB). Objective:To evaluate the behavior of cardiac autonomic modulation in asthmatic children and adolescents with and without EIB after the Voluntary Eucapnic Hyperventilation (HEV) test. Methods: Cross-sectional study carried out with 54 asthmatics (51.9% female), aged between eight and 19 years, who underwent the HEV test. Forced expiratory volume in one second (FEV1) and heart rate variability (HRV) capture were captured before and up to 30 min after HEV. The diagnosis of EIB was confirmed by a fall in FEV1 greater than 10% compared to baseline. The analysis of generalized estimating equations was used to compare the HRV according to the BIE. Results: Thirty (55.5%) of asthmatics had EIB. HRV data were not different at rest between those with and without EIB. Subjects with EIB reduced the mean of the R-R intervals in relation to the baseline until 15 minutes of HEV. Individuals without EIB had increased parasympathetic activity compared to baseline (rMSSD and SD1) from 5 min after HEV (p<0.05).This parasympathetic increase in relation to baseline was seen in individuals with EIB after 25 minutes (rMSSD= 49.9±5.3 vs 63.5±7.2 and SD1= 35.3±3.7 vs 45.0 ±5.1, both with p<0.05). Conclusion: Young asthmatics with EIB present a delay in the increase of the parasympathetic component after HEV when compared to asthmatics without EIB, suggesting that, in addition to pulmonary impairment.