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.

Importance of exercise training session duration in the rehabilitation of coronary artery disease patients.

BACKGROUND: In cardiac rehabilitation, 40-60-min exercise training sessions are advised. However, because of the increasing coronary artery disease (CAD) prevalence and higher workload for cardiac rehabilitation centres, it remains unclear whether 40-min exercise training sessions are equally effective as 60-min exercise training sessions. DESIGN: Prospective randomized clinical trial. METHODS: One hundred and thirty-four CAD patients were included in a 7-week rehabilitation programme. All patients exercised 3 days per week, at a heart rate corresponding to 65% of baseline peak oxygen uptake (VO2peak). Patients were randomized in two groups: 40 versus 60-min exercise training sessions. Changes of body anthropometrics, resting haemodynamics, exercise capacity and ventilatory threshold, blood plasma lipid profile and C-reactive protein level were assessed. RESULTS: As a result of rehabilitation, exercise capacity, ventilatory threshold, and blood plasma lipid profile improved significantly in the total population (P<0.05), without differences between subgroups (P>0.05). Body weight and waist circumference decreased significantly in total population (P<0.01), but with a greater magnitude in the 40 versus 60-min exercise session group (P<0.05). CONCLUSIONS: In the early rehabilitation of CAD patients, 40-min exercise training sessions seem to be at least as effective for improving body anthropometrics, blood plasma lipid profile and exercise capacity, as compared with 60-min exercise training sessions.