Exercise training intensity determination in cardiovascular rehabilitation: Should the guidelines be reconsidered?

AIMS: In the rehabilitation of cardiovascular disease patients a correct determination of the endurance-type exercise intensity is important to generate health benefits and preserve medical safety. It remains to be assessed whether the guideline-based exercise intensity domains are internally consistent and agree with physiological responses to exercise in cardiovascular disease patients. METHODS: A total of 272 cardiovascular disease patients without pacemaker executed a maximal cardiopulmonary exercise test on bike (peak respiratory gas exchange ratio >1.09), to assess peak heart rate (HRpeak), oxygen uptake (VO2peak) and cycling power output (Wpeak). The first and second ventilatory threshold (VT1 and VT2, respectively) was determined and extrapolated to %VO2peak, %HRpeak, %heart rate reserve (%HRR) and %Wpeak for comparison with guideline-based exercise intensity domains. RESULTS: VT1 was noted at 62 ± 10% VO2peak, 75 ± 10% HRpeak, 42 ± 14% HRR and 47 ± 11% Wpeak, corresponding to the high intensity exercise domain (for %VO2peak and %HRpeak) or low intensity exercise domain (for %Wpeak and %HRR). VT2 was noted at 84 ± 9% VO2peak, 88 ± 8% HRpeak, 74 ± 15% HRR and 76 ± 11% Wpeak, corresponding to the high intensity exercise domain (for %HRR and %Wpeak) or very hard exercise domain (for %HRpeak and %VO2peak). At best (when using %Wpeak) in only 63% and 72% of all patients VT1 and VT2, respectively, corresponded to the same guideline-based exercise intensity domain, but this dropped to about 48% and 52% at worst (when using %HRR and %HRpeak, respectively). In particular, the patient's VO2peak related to differently elicited guideline-based exercise intensity domains (P < 0.05). CONCLUSION: The guideline-based exercise intensity domains for cardiovascular disease patients seem inconsistent, thus reiterating the need for adjustment.

Neuromuscular electrical stimulation as a possible means to prevent muscle tissue wasting in artificially ventilated and sedated patients in the intensive care unit: A pilot study.

OBJECTIVE: The aim of this study was to explore if electrical stimulation could prevent muscle atrophy. MATERIAL AND METHODS: Patients were hospitalized for postoperative coronary artery bypass graftin, chronic obstructive pulmonary disease, ventilatory failure, or acute cerebro-vascular accident, and were divided into an intervention group or a control group. The intervention group underwent daily 30 minute training with an intermittent neuromuscular electrical stimulation applied to the right quadriceps muscle. Heart rate, respiration rate, systolic and diastolic blood pressure, and oxygen saturation were monitored before, during, and after electrical stimulation. Circumference of both thighs was measured. RESULTS: The intervention resulted in a significant reduction of muscle atrophy in the stimulated as compared with the non-stimulated limb (p < 0.05), without making any impact on cardiovascular, respiratory and, hemodynamic characteristics. CONCLUSIONS: Muscle atrophy is prevented by intermittent neuromuscular electrical stimulation while this intervention showed no obvious impact on the cardio-respiratory conditions of the patients.