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

Abstract

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.

Secondary prevention through comprehensive cardiovascular rehabilitation: From knowledge to implementation. 2020 update. A position paper from the Secondary Prevention and Rehabilitation Section of the European Association of Preventive Cardiology

“…15,16 The determination of exercise intensity during cardiac rehabilitation is a key issue and this position paper confirms previous indications regarding the identification of different intensity domains by direct and indirect methods. 15 Recent research, 17 however, revealed insufficient consistency between intensity domains as evaluated by different parameters obtained by cardiopulmonary exercise testing (CPET) -percentage of peak oxygen uptake (%VO 2peak ), peak heart rate (% HR peak ), heart rate reserve (%HRR) and power output (%W peak ) -at least in patients who are able to deliver maximal effort during CPET and in which the first and second ventilatory thresholds are both detectable, thus claiming a need for adjustment. Further research is needed to obtain new indications for exercise intensity prescription and guidance for increase during cardiac rehabilitation activities; however, already by now it seems reasonable to recommend a more individualized prescription by combining different variables obtained by CPET (possibly with increased consideration of %W peak ), and by matching them systematically with individual rating of perceived exertion (RPE) score or talk test (preferentially).…”

Fractal Correlation Properties of Heart Rate Variability: A New Biomarker for Intensity Distribution in Endurance Exercise and Training Prescription?

“…In a study looking at time spent in each training zone with heart rate and speed defined by gas exchange parameters, a greater fraction of relative time was spent in zone 2 if the zone was defined by a subjects heart rate rather than running speed (Bellinger et al, 2019 ). Of importance is also the observation that both VT1 and VT2 do not correlate well with fixed percentages of either maximum heart rate, VO 2MAX or maximum aerobic power in diverse populations (Peiffer et al, 2008 ; Azevedo et al, 2011 ; Hansen et al, 2019 ; Iannetta et al, 2020 ), making training recommendations based on these pre-set metrics problematic. Evaluating performance outcomes using fixed lactate values (Stöggl and Sperlich, 2014 ) or different measures of LT1/VT1 (Esteve-Lanao et al, 2007 ; Muñoz et al, 2014 ; Manunzio et al, 2016 ) have also led to inconsistent results as their comparison is difficult for the following reasons.…”

Do we have to reconsider the guidelines for exercise intensity determination in cardiovascular rehabilitation?

“…All other patients' characteristics could not explain these discrepancies. 11 These interesting observations clearly show that we may reach wrong decisions when prescribing exercise training if we follow the guideline-based exercise intensity domains because in some cases exercise prescription could be too challenging (i.e. low fitness patients) whilst in others (i.e.…”