Rafael E. Castro

Exercise training improves ambulatory blood pressure but not arterial stiffness in heart transplant recipients.

BACKGROUND Hypertension is the most prevalent comorbidity after heart transplantation (HT). Exercise training (ET) is widely recommended as a key non-pharmacologic intervention for the prevention and management of hypertension, but its effects on ambulatory blood pressure (ABP) and some mechanisms involved in the pathophysiology of hypertension have not been studied in this population. The primary purpose of this study was to investigate the effects of ET on ABP and arterial stiffness of HT recipients. METHODS 40 HT patients, randomized to ET (n = 31) or a control group (n = 9) underwent a maximal graded exercise test, 24-hour ABP monitoring, and carotid-femoral pulse wave velocity (PWV) assessment before the intervention and at a 12-week follow-up assessment. The ET program was performed thrice-weekly and consisted primarily of endurance exercise (40 minutes) at ~70% of maximum oxygen uptake (Vo2MAX). RESULTS The ET group had reduced 24-hour (4.0 ± 1.4 mm Hg, p < 0.01) and daytime (4.8 ± 1.6 mm Hg, p < 0.01) systolic ABP, and 24-hour (7.0 ± 1.4 mm Hg, p < 0.001) daytime (7.5 ± 1.6 mm Hg, p < 0.001) and nighttime (5.9 ± 1.5 mm Hg, p < 0.001) diastolic ABP after the intervention. The ET group also had improved Vo2MAX (9.7% ± 2.6%, p < 0.001) after the intervention. However, PWV did not change after ET. No variable was changed in the control group after the intervention. CONCLUSIONS The 12-week ET program was effective for reducing ABP but not PWV in heart transplant recipients. This result suggests that endurance ET may be a tool to counteract hypertension in this high-risk population.

Inflammatory biomarkers and effect of exercise on functional capacity in patients with heart failure: Insights from a randomized clinical trial:

Background In patients with heart failure, inflammation has been associated with worse functional capacity, but it is uncertain whether it could affect their response to exercise training. We evaluated whether inflammatory biomarkers are related to differential effect of exercise on the peak oxygen uptake (V˙O2) among patients with heart failure. Design Open, parallel group, randomized controlled trial. Methods Patients with heart failure and ejection fraction ≤0.4 were randomized into exercise training or control for 12 weeks. Patients were classified according to: 1) inflammatory biomarkers blood levels, defined as ‘low’ if both interleukin-6 and tumor necrosis factor-alpha blood levels were below median, and ‘high’ otherwise; and 2) galectin-3 blood levels, which also reflect pro-fibrotic processes. Results Forty-four participants (50 ± 7 years old, 55% men, 25% ischemic) were allocated to exercise training (n = 28) or control (n = 16). Exercise significantly improved peak V˙O2 among participants with ‘low’ inflammatory biomarkers (3.5 ± 0.9 vs. −0.7 ± 1.1 ml/kg per min, p = 0.006), as compared with control, but not among those with ‘high’ inflammatory biomarkers (0.4 ± 0.6 vs. −0.2 ± 0.7 ml/kg per min, p = 0.54, p for interaction = 0.009). Similarly, exercise improved peak V˙O2 among participants with below median (2.4 ± 0.8 vs. −0.3 ± 0.9 ml/kg per min, p = 0.032), but not among those with above median galectin-3 blood levels (0.3 ± 0.7 vs. −0.7 ± 1.0 ml/kg per min, p = 0.41, p for interaction = 0.053). Conclusion In patients with heart failure, levels of biomarkers that reflect pro-inflammatory and pro-fibrotic processes were associated with differential effect of exercise on functional capacity. Further studies should evaluate whether exercise training can improve clinical outcomes in patients with heart failure and low levels of these biomarkers.

Prescribing and regulating exercise with RPE after heart transplant: a pilot study

PURPOSE The objective of this study is to analyze the use of the 6-20 RPE scale for prescribing and self-regulating heated water-based exercise (HEx) and land-based exercise (LEx) in heart transplant recipients. METHODS Fifteen (five females) clinically stable heart transplant recipients (time since surgery = 4.0 ± 2.5 yr) age 46.7 ± 11.8 yr underwent a symptom-limited maximal graded exercise test on a treadmill to determine their HR at anaerobic threshold (HRAT), respiratory compensation point (HRRCP), and maximal effort (HRmax). After a week, patients were randomized to perform 30 min of both HEx (walking inside the pool) and LEx (treadmill walking) sessions at a pace between 11 and 13 on the 6-20 RPE scale and had their HR measured every 4 min. The interval between sessions was 48-72 h. RESULTS No significant differences between sessions were found in the average HR during HEx and LEx. Patients showed a delay in HR increase during both interventions, with the stabilization beginning after 8 min of exercise. Exercise HR was maintained between the HRAT and HRRCP (in the aerobic exercise training zone) for the most part of both HEx (72% of HR measurements) and LEx (66% of HR measurements). Only a few HR measurements stayed below HRAT (HEx = 9%, LEx = 13%) or above HRRCP (HEx = 19%, LEx = 21%) during both exercise sessions. CONCLUSION Exercise HR was maintained in the aerobic exercise training zone (between HRAT and HRRCP) for the most part of both sessions, suggesting that the 6-20 RPE scale may be an efficient tool for prescribing and self-regulating HEx and LEx in heart transplant recipients.

Postexercise Hypotension after Heart Transplant: Water- versus Land-Based Exercise.

PURPOSE Heart transplant recipients (HTx) have a high prevalence of hypertension. Although exercise training promotes blood pressure (BP) reduction in HTx, the effects of a single exercise bout are unknown. Thus, we analyzed the acute effects of heated water-based exercise (HEx) versus land-based exercise (LEx) on ambulatory BP (ABP) in HTx. METHODS Eighteen (six females) clinically stable HTx (time since surgery = 5.0 ± 0.7 yr) age 45.7 ± 2.7 yr underwent 30 min of HEx (walking inside the pool), LEx (walking on a treadmill), and nonexercise control (CON) intervention in random order (2-5 d between interventions). HEx and LEx intensity was set at 11-13 in the 6-20 RPE scale. Twenty-four-hour (24-h) ABP monitoring was performed after each intervention. RESULTS No significant differences between interventions were found in 24-h and nighttime BP. However, daytime diastolic BP was significantly lower after HEx than CON (-4 ± 1.6 mm Hg, P = 0.03), and daytime diastolic BP tended to be lower after LEx than CON (-2.3 ± 1.1 mm Hg, P = 0.052). Hourly analysis showed that systolic and diastolic BP values were lower after HEx (average reductions of 6.6 to 12.3 mm Hg, P < 0.01) and LEx (average reductions of 5 to 8.3 mm Hg, P < 0.05) than after CON in several hours. No significant differences between HEx and LEx were found in any ABP data. CONCLUSION HEx and LEx promoted similar reductions in ABP of heart transplant recipients, which suggests that they may be a tool to counteract hypertension in this high-risk population.

INTERLEUKIN-6 AND GALECTIN-3 ARE LOWER IN PATIENTS WITH HEART FAILURE WHO DO NOT RESPONSE TO EXERCISE TRAINING

Exercise training can improve functional capacity in patients with heart failure (HF), but the response is heterogeneous. Change in peak oxygen consumption (peak VO2) after an exercise program is related to survival in this population. We sought to investigate if there are any differences in