The sympathetic branch arouses to sustain the adaptation to stressors, although faster parasympathetic adjustments are responsible of immediate adaptive changes (e.g. anxiety control before a demanding concert). Sometimes this vagal control fails, like in Music Performance Anxiety (MPA) (1). Recent studies showed a decrease in the High Frequency index (HF) (2), a vagal index under the indirect modulatory control of the cortical-amygdala neurocircuitry, in the basis of emotion regulation (3). These studies also reflect an increase in the LF/HF (Low Frequency/High Frequency ratio) with unclear results for the former LF (2). On the other hand, the High Intensity Interval Training (HIIT) has been associated to a vagal improvement and a reduction of the sympathetic arousal in long-term interventions (4), but little is Known about short acute proposals. This study aims to analyze the changes in the frequency indices of HRV after one week of HIIT in a group of young musicians facing a demanding concert. 12 healthy male wind-instrumentalists (23±4.88y; 78.86±11.46kg) performed two concerts in one week. 48h after the first concert they underwent a graded cycling test until voluntary exhaustion (15-W increase per 1-min, Tacx flow ergometer, Tacx, Wassenaar, Netherlands) for high intensity familiarization and medical supervision. 48h later, musicians conducted 2-to-4 30-s cycling all-out Wingates, interspersed with 4 min of recovery (187.90±12.25 bpm; 11.70±3.38 mmol/L-1 lactate; 9.60±1.07 RPE on Borg 10 scale). 5 min of a 10-min Heart Rate recording in sitting-position (Polar rx800), were retained twice for HRV analysis (Kubios, 2.1): fasting in the morning, in baseline condition (BS), and immediately before the concert (BC). Wilcoxon test showed BC pre-post training changes in LF/HF ratio (p<0.05; 3.05±2.75 vs 1.68±1.29 ms2), and a slight trend toward a significant improvement in HF (p=0.07; 1119.50±1356.96 vs 2097.94±2868.36 ms2), with no significant differences for LF (1870.15±2386.33 vs 2154.34±2148.79 ms2). The improvement was no significant in BS (LF/HF: 2.76±3.56 vs 1.51±1.07 ms2; HF: 2872.67±3324.60 vs 3308.11±3641.26 ms2; LF: 3444.06±3523.09 vs 3212.49±2824.80 ms2). Despite the short time of the intervention and the reduced sample, our results support the hypothesis that the parasympathetic reactivation and the better vagal balance following HIIT (5) might be helpful in the control of MPA. LF/HF ratio and HF, which were susceptible to extraordinary stressful events (2), are also susceptible to benefit from acute HIIT interventions. New studies will show if longer recovery following exercise might show BS vagal reactivation. Lack of time among professional musicians might suggest that HIIT is a short-term efficient solution for MPA.