Cardiac Autonomic Modulation and Lower Limbs Resistance Exercise in Healthy Elderly: A Cross-Sectional Study

Aim: Assess the cardiac autonomic modulation during and after lower limbs resistance exercise (RE) in elderly compared to young.Methods: Fifteen elderly (66 +/- 5 years) and 15 young (25 +/- 4 years) underwent a RE protocol on the Leg Press at 70% of one repetition maximum. Parasympathetic indices (LnSD1 and LnRMSSD) were obtained through ultra-short-term heart rate variability analyze at resting, peak, and recovery (1, 3, 5, 10, and 15 min); in addition, heart rate recovery (HRR) was obtained.Results: At the peak effort: LnSD1 and LnRMSSD were higher in the elderly compared to young (LnSD1: 0.65 +/- 0.21 vs. 0.44 +/- 0.22, p < 0.05; LnRMSSD: 0.81 +/- 0.21 vs. 0.58 +/- 0.23, p < 0.05); and at recovery phase: attenuated HRR and lower parasympathetic response were found to elderly compared to young (p < 0.05).Conclusion: At the peak of RE, greater parasympathetic modulation was observed in elderly compared to young, and during recovery lower parasympathetic modulation and attenuated HRR were found in elderly.