Acute effects of resistance exercise on heart rate variability in cardiopathic patients: Cross-sectional study

Abstract

Background: Resistance exercise is used in clinical practice to improve muscle strength and resistance of patients with heart disease. However, it lacks studies regarding its acute effects on cardiac autonomic modulation. This cross-sectional study has aimed to evaluate the acute effects of resistance exercise on heart rate variability (HRV) in cardiopathic patients. Methods: We investigated 15 volunteers (63.8 ± 10.7 years old; 29.9 ± 4.32 Kg/m²), which were submitted to one maximal repetition (1RM) of knee extension and to the acute interventions with of 40% and 80% of 1RM, with minimal intervals of 48 hours. HRV was analyzed in the SDNN, RMSSD, Poincaré Plot, HF, LF, and LF/HF ratio indexes. We evaluated HRV in the periods of rest (10 min) and recovery (60 minutes, divided into 6 windows). Findings: No differences were observed between the immediate recovery and rest periods for all indexes. We observed increase in all indexes after 20 minutes of recovery. No differences were verified between the different protocols. Conclusion: a single acute session of resistance exercise in different intensities did not change the cardiac autonomic modulation.