Cardiac autonomic modulation during progressive upper limb exercise by patients with coronary artery disease

ABSTRACT

The purpose of this study was to investigate the behavior of heart rate (HR) and HR variability (HRV) during different loads of resistance exercise (incline bench press) in patients with coronary artery disease (CAD) and healthy sedentary controls. Ten healthy men (65 ± 1.2 years, control group, CG) and 10 men with clinically stable CAD (66 ± 2.4 years, CADG) were recruited. A discontinuous progressive protocol was applied with an initial load of 10 percent of the maximum load achieved in the 1RM (1 repetition maximum) with increases of 10 percent until 30 percent 1RM was reached, which was followed by subsequent increases of 5 percent 1RM until exhaustion. HRV was analyzed by linear and non-linear methods. There was a significant reduction in rMSSD (CG 20 ± 2 to 11 ± 3 ms; CADG 19 ± 3 to 9 ± 1 ms) and SD1 indexes (CG 14 ± 2 to 8 ± 1 ms; CADG 14 ± 2 to 7 ± 1 ms). An increase in HR (CG 69 ± 5 to 90 ± 5 bpm; CADG 62 ± 4 to 75 ± 4 bpm) and in systolic blood pressure (CG 124 ± 3 to 138 ± 3 mmHg; CADG 122 ± 6 to 126 ± 9 bpm) were observed (P < 0.05) when comparing pre-effort rest and 40 percent 1RM in both groups. Furthermore, an increase in RMSM index was also observed (CG 28 ± 3 to 45 ± 9 ms; CADG 22 ± 2 to 79 ± 33 ms), with higher values in CADG. We conclude that loads up to 30 percent 1RM during incline bench press result in depressed vagal modulation in both groups, although only stable CAD patients presented sympathetic overactivity at 20 percent 1RM upper limb exercise.