Assessment of Exercise Intensity in Cardiac Rehabilitation Programmes for Patients With Chronic Heart Failure

Cardiac rehabilitation is the ideal comprehensive intervention for patients with chronic heart failure (CHF), since it addresses the complex interplay of medical, psychological and behavioural factors facing these individuals. Structured exercise training within a cardiac rehabilitation programme is firmly recommended for these patients. However, it is questionable whether patients are achieving an adequate dose of exercise to provide optimal benefits. The essential components for setting optimal training include the appropriate mode, duration, frequency and intensity of exercise. UK surveys of cardiac rehabilitation describe the frequency and duration of training, but here is scant information on exercise intensity. However, it is apparent that randomised controlled trials of exercise training use doses more than 4 times greater than in UK current practice. The Eastbourne Exercise Cardiology Research Group has demonstrated that although patients benefit from improved quality of life and submaximal fitness after a hospital outpatient cardiac rehabilitation programme, they do not achieve the increases in important prognostic indicators reported by the majority of exercise training trials.

The critical factor in terms of eliciting a sufficient training effect while minimising risk is the intensity of the exercise performed. It is now widely accepted that the traditional methods of using fixed percentages of maximal heart rate or oxygen uptake to set exercise intensity include serious errors. The European Society of Cardiology recommends that cardiopulmonary exercise testing should be used to provide an objective evaluation of the metabolic demand of exercise. This allows physiologically meaningful reference points to be established for aerobic exercise prescription and is the solution to defining safe and effective training intensities. The next step is to determine whether this information can be transferred to a practical cardiac rehabilitation environment to set and monitor exercise intensity