Acute effects of high-intensity interval training and moderate-intensity continuous training on linear and nonlinear heart rate variability measures in arterial hypertension

Abstract

Introduction: Systemic arterial hypertension is a chronic disease worldwide. High-intensity interval training (HIIT) has been described as an effective alternative treatment. Objective: To evaluate the acute effects of one HIIT session versus one moderate-intensity continuous training (MICT) on linear and nonlinear heart rate variability (HRV) measures in hypertension patients. Methods: A preliminary cross-sectional study with 11 non-elderly (35 to 59 years) hypertensive patients using drug therapy from both sexes. They were assigned for cardiological evaluation, ergometric test, echocardiography, and cardiopulmonary exercise test. Patients performed cycling exercise in the conditions HIIT (10 bouts of 1-minute at 85% of the maximum power [Pmax] interspersed with 2 minutes at 50% of Pmax) and MICT (30 minutes at 50% of Pmax). R-R intervals (RRi) of HRV were recorded in the supine position for 10 minutes before and after the two exercise conditions. Results: HIIT and MICT presented a significant reduction (P<0.01) for the RRi between baseline (pre-session) and post-session. All other linear indices presented similar results (P>0.05) between moments. Significant differences (P<0.05) in the symbolic HRV analysis were identified only in the HIIT group for 0V, 2LV, and 2ULV indexes. 0V index increased 2.3-times from pre- to post-session while 2LV and 2ULV indexes reduced to near 50% and 35%, respectively. Conclusion: An increase in sympathetic modulation with a significant decrease in vagal modulation by nonlinear HRV measures was identified in patients with hypertension submitted to one HIIT session.