The Acute and Chronic Effects of Beta Blockade on Dynamic Exercise Performance and Cardiac Adaptation to Dynamic Exercise Training

Widespread use of beta-adrenergic blocking agents as treatments for hypertension, ischemic heart disease and postmyocardial infarction has raised many questions concerning the effect of these drugs during exercise. Since exercise is often prescribed as an adjunct treatment in combination with beta blockade, the effect of these drugs on cardiac function during exercise is important to know. It is also important to ascertain if patients taking beta blockers will benefit from chronic dynamic exercise training the same way as normal subjects or if they should be viewed differently. This review of the current biomedical literature is meant to elucidate the cardiac effects, both acute and chronic, of beta-adrenoceptor blockade during dynamic exercise. The acute effects during dynamic exercise and the compensatory mechanisms in the cardiovascular system will be outlined. I will further explore if and how beta blockade significantly affects cardiac adaptation to chronic exercise training. Be reviewing the current literature I will show what is already known and will demonstrate where current knowledge is lacking and where further research is needed. There are two questions which will be addressed by this research. The first question is: “What happens to the cardiovascular system during dynamic exercise when a beta blocker is present in the system?” This question deals with the acute effects of such agents on exercise performance and cardiac function. The second question is: “What effect does beta blockade have on the cardiac adaptations to chronic dynamic exercise training?” This question examines areas of cardiac adaptation that have been postulated to be mediated by beta-adrenergic receptor stimulation (e.g. myocardial hypertrophy). I hypothesize that the acute effects of beta blockade on exercise performance are minimal, while the chronic effects on cardiac adaptation to dynamic exercise training may be significant.