An exercise-based CR program involves:
- assessing the patient’s baseline ability, limitations and cardiovascular risk
- developing an exercise prescription (see below)
- observing the patient’s response to that prescription and adjusting the prescription as necessary
- encouraging long-term participation in regular unsupervised exercise.
An appropriate exercise prescription, in parallel with a medication prescription, includes type of activity (mode) and location (centre-based or home-based), duration (how long for each session and for the program) and frequency (usually on a weekly basis), intensity (dose) and, very importantly, progression.
Low-impact aerobic exercises such as walking, cycling, rowing and machine stair climbing (that use large muscle groups) are all effective. The mode(s) of exercise chosen should be enjoyable for the individual and simple to carry out to maximise compliance. People with joint problems generally tolerate cycling better than walking.
Frequency and duration
The recommended frequency of exercise is at least three times a week (this can be a combination of supervised and unsupervised sessions), but preferably on most days of the week. This is necessary to achieve a significant improvement in functional capacity. Each session includes three phases: warm up (5–10 minutes), training phase (20–45 minutes of continuous or discontinuous aerobic activity) and cool down (5–10 minutes).
Programs vary in their duration, but 6–8 weeks is common in Australia.
Exercise intensity can be specified as a heart rate, a speed and grade of a treadmill/stationary cycle, or using the rating of perceived exertion (RPE or Borg scale), which most patients can learn and apply easily during unsupervised exercise.
The exercise intensity for healthy adults is usually a 12 to 13 (somewhat hard) on the RPE scale. This corresponds to 60–70% of functional capacity. Individuals with a low baseline fitness level, which is often the case with cardiac patients, should begin at a lower percentage of capacity (eg equivalent to a rating of exertion of 11 on the Borg scale).
The incremental benefit of very high intensity exercise (>90% capacity) is small and is not recommended because it leads to lactate accumulation and fatigue, and increases the risk of physical injury and cardiovascular complications.
The exercise prescription is progressed according to patient tolerance, motivation and goals, symptoms, baseline fitness level and musculoskeletal limitations.