Author’s Reply

We agree with Froehlich et al. [2] that evidence suggests that collateralisation of the coronary circulation may explain, at least in part, the improvement in symptoms and survival seen in active CAD patients. In our study physical functioning was improved but angina frequency and severity were unchanged. The timeline for collateralisation may be within the 8-week treatment duration of our study, as Belardinelli et al. [5] showed that 8 weeks of moderate exercise increased collateral blood flow significantly on thallium scanWe thank the readers for their interest in our article [1] and for their insightful comments. We used cardiac rehabilitation in our study as it is a prescribable and reproducible form of exercise that suited the needs of a controlled research study. As Froehlich et al. [2] discuss, exercise, or more generally physical activity, is ben eficial to the symptoms and survival of patients with coronary artery disease (CAD). Patients with other cardiovascular pathologies such as heart failure and chest pain syndromes also benefit from exercise [3, 4] . Received and accepted: August 21, 2012 Published online: September 25, 2012