Higher Weekly Walking Volume Improves Cardiac Autonomic Profile and Arterial Stiffness Index in Hypertensive Elderly

Abstract

Background The practice of daily aerobic exercise such as healthy walking could have an important effect on cardiovascular parameters. However, there is still little evidence of how much weekly walking volume is enough to influence cardiovascular autonomic modulation and arterial stiffness on hypertension. Purpose To assess effects of weekly walking volume on cardiac autonomic function and arterial stiffness index in elderly hypertensive. Methods Sixty hypertensive elderly with 71.7 ± 3.4 years old were allocated in physically inactive (PI, n=30) and active (PA, n=30) groups. Hemodynamic parameters of heart rate (HR), peripheral blood pressure (SYS, DIA, MBP), cardiac autonomic modulation by the method of HR variability in both the time (root mean square of successive differences (RMSSD) and percentage of RR intervals differing by <50ms (pNN50)) and frequency domains (low and high frequency (LF, HF), and LF/HF ratio), stiffness (augmentation index; AIX, pulse wave velocity; PWV) and total vascular conductance (TVC), and central blood pressure (cSYS, cDIA) were measured in baseline conditions. Results The average of weekly walk in PA group was 312.4 ± 36.5 min. vs. 57.7 ± 47.9 min. in PI group (p <0.001). Pronounced resting bradycardia was observed in PA group (62.1 ± 8.7 bpm) in comparison with PI group (75.7 ± 9.1; p=0.0). Brachial SYS (124.3 ± 7.6 mmHg) DIA (76.5 ± 7.4 mmHg) and MBP (92.4 ± 7.4 mmHg) were lowers in PA than PI group (133.6 ± 6.0 mmHg; p=0.003), (82.7 ± 7.6 mmHg; p=0.032) and (99.4 ± 7.0 mmHg; p<0.05), respectively. The PA group showed higher cardiac parasympathetic modulation than PI group, evidenced by an increase in RMSSD (PI: 43.8 ± 23.9 vs. PA: 69.4 ± 29.4 ms; p=0.047), pNN50 (22.7 ± 3.9 vs. 40.7 ± 5.1 %; p=0.038) and in cardiac HF band (PI: 59.9 ± 5.8 vs. PA: 67.0 ± 3.7 nu; p=0.005). There were no differences in sympathetic modulation between PA and PI groups. The PI group had higher PWV (10.3 ± 1.2 m/s), AIX (36.4 ± 8.0 %) and TVC (1.4 ± 0.1 s*mmHg/ml) when compared to PA group (PWV = 9.1 ± 0.7 m/s; p = 0.005), (AIX = 23.5 ± 13.6 %; p = 0.003) and (TVC = 1.2 ± 0.1 s*mmHg/ml; p <0.001). Additionally, the cSYS (119.5 ± 14.0 mmHg) and cDIA (76.2 ± 18.3 mmHg) were lower in PA than PI (135.8 ± 20.6 mmHg; p=0.045 and 91.8 ± 20.5 mmHg; p=0.034), respectively. Conclusion These findings suggest that a higher weekly volume of walking improves baseline hemodynamic parameters and provides greater vagal modulation at rest, concomitant with attenuation of arterial stiffness evidencing that this type of intervention has important cardiovascular safety. Support or Funding Information CAPES, CNPq, FAPEMIG, UFTM.