The Effect of Aquatic Exercise Training on Heart Rate Variability in Patients with Coronary Artery Disease

Abstract

(1) Background: Aquatic exercise training is a relatively understudied exercise modality in patients with CAD; with the present study, we sought to compare the impact of short-term 14-day water- and land-based exercise training on heart rate variability (HRV). (2) Methods: We randomized 90 patients after a recent CAD event (myocardial infarction and/or revascularization within 2 months prior to inclusion) to either (i) water-based or (ii) land-based exercise training (14 days, two 30 min sessions daily), or (iii) controls. Before and after the intervention period, all participants underwent 20 min 12-channel high-resolution ECG recordings with off-line HRV analysis, including conventional linear time- and frequency-domain analysis (using the Welch method for fast-Fourier transformation), and preselected non-linear analysis (Poincaré plot-derived parameters, sample entropy, and the short-term scaling exponent α1 obtained by detrended fluctuation analysis). (3) Results: Eighty-nine patients completed the study (mean age 60 ± 8 years; 20 % women). We did not detect significant differences in baseline- or age-adjusted end-of-study HRV parameters, but aquatic exercise training was associated with a significant increase in the linear LF/HF parameter (from 2.6 [1.2–4.0] to 3.0 [2.1–5.5], p = 0.046) and the non-linear α1 parameter (from 1.2 [1.1–1.4] to 1.3 [1.2–1.5], p = 0.043). (4) Conclusions: Our results have shown that a short-term 14-day aquatic exercise training program improves selected HRV parameters, suggesting this mode of exercise is safe and may be beneficial in patients with CAD.

Effects of Water-Based Exercise on Patients Older than 60 Years Undergoing Cardiac Rehabilitation after Coronary Intervention

“…This sub-analysis utilizes some of our collected data from a prospective, randomized, open-label parallel trial comparing water-and land-based exercise training with nonsupervised training in CAD patients undergoing stationary cardiac rehabilitation, published previously by our research group [9,10].…”

“…The eligibility criteria for this study have been previously described [9,10]. CAD patients within three months post-myocardial infarction and revascularization (percutaneous coronary intervention (PCI) or coronary artery bypass graft (CABG)) undergoing stationary cardiac rehab were enrolled.…”

“…Eligible patients were invited to join this study. This study included 89 patients: 29 in the water-based group, 30 in the land-based group, and 30 in the control group [9,10].…”

“…Before training, all participants underwent standard symptom-limited cardiopulmonary bicycle testing using the Schiller CS-200 cycle ergometer (Schiller A.G. Baar, Switzerland), with an incremental ramp protocol aiming for the predicted maximal workload. The test was considered complete if the respiratory exchange ratio was ≥1.1, and it was monitored continuously by ECG [9,10].…”

“…Patients refrained from smoking or consuming caffeinated beverages 24 h before the recordings. Measurements were conducted between 9 and 11 AM in the fed state, following a short supine rest (10 min) in a controlled environment (quiet room, temperature: 22-24 • C, and humidity: 40-70%) [9].…”