High level physical activity in cardiac rehabilitation: Implications for exercise training and leisure-time pursuits

Importance: Regular moderate-to-vigorous physical activity and increased levels of cardiorespiratory fitness (CRF) are widely promoted as cardioprotective measures in secondary prevention interventions. Observations: A lowlevel of CRF increases the risk of cardiovascular disease (CVD) to a greater extent than merely being physically inactive. An exercise capacity <5 metabolic equivalents (METs), generally corresponding to the bottom 20% of the fitness continuum, indicates a highermortality group. Accordingly, a key objective in early cardiac rehabilitation (CR) is to increase the intensity of training to >3 METs, to empower patients to vacate this high risk group. Moreover, a good exercise capacity, expressed as peakMETs, identifies individualswith a favorable long-term prognosis, regardless of the underlying extent of coronary disease. On the other hand, vigorous-to-high intensity physical activity, particularly when unaccustomed, and some competitive sports are associated with a greater incidence of acute cardiovascular events. Marathon and triathlon training/competition also have limited applicability and value in CR, are associatedwith acute cardiac events each year, and do not necessarily provide immunity to the development of or the progression of CVD. Furthermore, extremeendurance exercise regimens are associated with an increased incidence of atrial fibrillation and accelerated coronary artery calcification. Conclusions and relevance: High-intensity training offers a time-saving alternative to moderate intensity continuous training, as well as other potential advantages. Additional long-term studies assessing safety, adherence, and morbidity and mortality are required before high-intensity CR training can be more widely recommended, especially in previously sedentary patientswith known or suspected CVD exercising in non-medically supervised settings. (C) 2021 Elsevier Inc. All rights reserved.

Automated summary

Regular moderate-to-vigorous physical activity and increased levels of cardiorespiratory fitness are important for cardioprotection. Low cardiorespiratory fitness increases the risk of cardiovascular disease, while good exercise capacity indicates a favorable long-term prognosis. However, high-intensity physical activity and some competitive sports are associated with a higher incidence of acute cardiovascular events, and extreme endurance exercise regimens are linked to an increased risk of atrial fibrillation and coronary artery calcification.