Number 26, 2005
Cardiovascular effects of exercise

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Mario Marzilli
Department of Cardiology, University of Siena, Italy
Correspondence: Mario Marzilli, Department of Cardiology, University of Siena, Policlinico Le Scotte, V. Le Bracci, 53100 Siena, Italy.
E-mail: marzilli@unisi.it

Physical inactivity doubles the risk of developing heart disease and increases the risk of hypertension by 30%. It also doubles the risk of dying from cardiovascular disease and stroke. Every year, more than 2 million deaths are attributable to physical inactivity worldwide.
Moderate and high levels of physical activity are associated with a reduced risk of cardiovascular disease and all-cause mortality. Physical activity acts through many metabolic pathways that affect cardiovascular risk factors. It improves the plasma lipid profile, reduces body weight, decreases blood pressure, reduces platelet aggregation, increases fibrinolytic activity, improves cardiac function, improves cardiorespiratory fitness, and decreases the resting heart rate. Furthermore, exercise training seems to improve endothelium-dependent vasodilatation and increase both urinary excretion of sodium and insulin sensitivity. Long-term exercise has been associated with a decrease in atherogenic activity of blood mononuclear cells and with decreased C-reactive protein concentrations.
Unfortunately, 60–85% of the world population, from both developed and developing countries, are not sufficiently physically active to gain health benefits. Promoting physical activity appears to be an essential component in the prevention of premature cardiovascular disease and all-cause-mortality.
In patients with chronic or post-acute cardiovascular disease, exercise therapy is consistently identified by international guidelines as a central element of cardiac rehabilitation. A recent meta-analysis has confirmed that exercise-based cardiac rehabilitation reduces both cardiac and total mortality, possibly through a direct effect on myocardial oxygen demand, endothelial function, autonomic tone, coagulation and clotting factors, inflammatory markers, and the development of coronary collaterals vessels.
In patients with heart failure, exercise training improves functional capacity and quality of life. The optimal form of training remains undefined, and although intermittent aerobic exercise appears to be effective, strength training alone may not be as effective as the standard approach of continuous aerobic exercise.
A regular physical exercise program improves symptom-free exercise tolerance and myocardial perfusion in patients with stable coronary artery disease, and retards the progression of coronary artery disease over time. Improved endothelium-dependent vasodilatation may represent the most important mechanism to explain the reduction in myocardial ischemia. In patients with stable coronary artery disease, a 12-month exercise training program resulted in a higher event-free survival rate than with standard percutaneous coronary intervention.
Michael Allard, in the basic article of this issue 26 of Heart and Metabolism, focuses on the differences in myocardial energy metabolism associated with pathologic and physiologic forms of cardiac hypertrophy. Non-invasive cardiac imaging can be of great help in the differential diagnosis between these two forms of cardiac hypertrophy. In general, as described by Eike Nagel and Ingo Paetsch, echocardiographic techniques are sufficient to diagnose cardiomyopathy. In difficult cases, magnetic resonance may provide additional conclusive information.
Harm Kuipers completes the description of cardiac adaptations to exercise, describing the effects of training on autonomic control and discussing the effects of pharmacologic interventions to improve performance.
Neil Smart and Thomas Marwick review the risk and benefits of exercise in cardiac disease. Their article is rich in useful recommendations to minimize exercise-related adverse events and maximize the benefit to the patient, beginning from the preclinical stage of cardiac disease.
Andrew McLeod offers a number of very useful tips for the construction of an exercise program, including technical and financial aspects.
The benefits of a metabolic approach to the improvement of cardiac function in chronic heart failure are reviewed by Hamayak Sisakyan and illustrated by Mario Marzilli in a case of severe heart failure.
In all, issue 26 of Heart and Metabolism offers a comprehensive overview of exercise as an effective addition to the therapeutic strategies for the prevention and treatment of cardiac diseases.