Evaluating the Benefits of Exercise Training in HFrEF or COPD Patients: ISO-LEVEL COMPARISON CAN ADD VALUABLE INFORMATION TO V˙o2peak.

BACKGROUND: Heart failure with reduced ejection fraction (HFrEF) and chronic obstructive pulmonary disease (COPD) are relatively common conditions with similar symptoms of exercise intolerance and dyspnea. The aim of this study was to compare exercise capacity, ventilatory response, and breathing pattern in patient groups with either advanced HFrEF or COPD before and after exercise training. METHODS: An observational study was conducted with parallel groups of 25 HFrEF and 25 COPD patients who took part in 6 wk of inpatient rehabilitation with exercise training. All patients underwent cardiopulmonary exercise tests at the start and end of the training, with resting arterial blood gas measurements. RESULTS: The average peak oxygen uptake (V˙o2) was low at the start of the study but increased significantly after training in both groups, or by 2.2 ± 2.1 mL/kg/min in HFrEF patients and 1.2 ± 2.2 mL/kg/min in COPD patients. At ISO-V˙o2 (ie, same level of V˙o2 in pre- and post-exercise tests), carbon dioxide production (V˙co2) decreased after exercise training in both groups. Similarly, at ISO-V˙E (ie, same level of ventilation), breathing frequency (f) decreased and tidal volume (VT) increased, resulting in an improved breathing pattern (lower f/VT ratio) after training. CONCLUSION: The findings of this study show that exercise training in severely affected patient groups with HFrEF or COPD led to an increase in maximal exercise capacity, a more favorable breathing pattern, and a diminished V˙co2 during exercise. Therefore, comparisons of V˙co2 and breathing pattern at ISO-levels of V˙o2 or V˙E before and after training are valuable and underutilized outcome measures in treatment studies.

Hemodynamic responses during aerobic and resistance exercise.

PURPOSE: Resistance training has become an accepted part of cardiac rehabilitation programs. Because of the potential for a high afterload to have a negative impact on left ventricular function, there has been concern regarding the safety of resistance training for patients with congestive heart failure. METHODS: This study addressed this concern by studying 12 healthy volunteers, 12 patients with stable coronary artery disease, and 12 patients with stable congestive heart failure during upright cycling at 90% of ventilatory threshold, and during one set of 10 repeated leg presses, shoulder presses, and biceps curls at 60% to 70% of 1-repetition maximum. Left ventricular function was measured by echocardiography. RESULTS: The pattern of changes in heart rate, blood pressure, left ventricular ejection fraction, wall thickness, and left ventricular internal diameters was similar across all three groups of subjects, although there were large differences in absolute values. Despite elevations in diastolic and mean arterial pressures during resistance exercise, there was no evidence of significant rest-to-exercise deterioration in left ventricular function during leg press (ejection fraction, 60%-59%, 56%-55%, and 38%-37%), shoulder press (66%-65%, 59%-53%, and 38%-35%), or biceps curls (63%-58%, 53%-54%, and 35%-36%), as compared with cycle ergometry (63%-69%, 51%-57%, and 35%-42%) in the healthy control subjects, the patients with coronary artery disease, and the patients with congestive heart failure, respectively. CONCLUSIONS: Left ventricular function remains stable during moderate-intensity resistance exercise, even in patients with congestive heart failure, suggesting that this form of exercise therapy can be used safely in rehabilitation programs.