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Summary

This chapter discusses the hemodynamic and health benefits of exercise in healthy individuals and those with or at risk of cardiovascular disease. The three different types of exercise — isotonic (dynamic), isometric (static), and resistance — impose different loads on the cardiovascular system. Exercise training increases oxygen consumption, cardiac stroke volume, maximal exercise cardiac output, and resting parasympathetic tone, and decreases resting sympathetic tone and resting heart rate. Thus, physical conditioning alters cardiac structure and function. Exercise has been shown to provide cardioprotection by reducing cardiovascular risk factors such as blood pressure, hyperlipidemia, weight, risk of diabetes, and possibly systemic inflammation (see accompanying Hurst’s Central Illustration). Credible data exist to support the benefits of a physically active lifestyle in older adults, but specific considerations must be addressed when prescribing exercise for elderly individuals. An individually prescribed physical activity/exercise program can also provide significant benefit to patients with stable cardiovascular disease. Studies indicate that exercise results in less progression and more regression of coronary artery disease, enhancement of endothelium-dependent coronary and peripheral arterial vasodilatation in individuals with coronary artery disease, peripheral artery disease, heart failure, diabetes, or hypertension, and functional and symptomatic improvement in patients with heart failure.

eFig 106-01

The cardiovascular effects of exercise in healthy individuals (primary prevention) and in patients with cardiovascular disease (secondary prevention). Exercise confers cardioprotection by reducing cardiovascular risk factors and also provides various additional cardiovascular benefits in patients with cardiovascular disease. HDL, high-density lipoprotein; LDL, low-density lipoprotein; VLDL, very low-density lipoprotein.

INTRODUCTION

Exercise and/or physical activity is beneficial for healthy individuals and for those at high risk for cardiovascular disease (CVD), as well as those with manifest CVD. This chapter addresses the hemodynamics and health benefits of physical activity and exercise conditioning programs, both in healthy individuals and those with or at risk for CVD.

ACUTE HEMODYNAMICS

During physical activity, energy expenditure increases, and the compensatory cardiovascular response represents an integration of neural, biochemical, and physiologic factors. The cardiovascular control center is believed to reside in the ventrolateral medulla of the brain and to respond to both central and peripheral inputs. Central impulses arise from somatomotor centers of the brain. Peripheral impulses are generated by mechanoreceptors, found in muscles, joints, and the vascular system; chemoreceptors, found in the muscles and the vascular system; and baroreceptors, found in the vascular system. These impulses are transmitted by autonomic afferent fibers. The central control center regulates cardiac output (CO) and its distribution to organs and tissues according to metabolic demand.

The feed-forward command system located in the motor cortex provides a coordinated and rapid cardiovascular response to optimize tissue perfusion and maintain central blood pressure. This central command provides the greatest control over heart rate (HR) during exercise1 and is also involved in the preexercise anticipatory response. ...

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