Age-related alterations in the cardiovascular response to adrenergic mediated stress.

Cardiovascular adaptation to stress is highly dependent on adrenergic stimulation. It may be hypothesized that the diminished cardiovascular response to acute stress that occurs in advanced age may result in part from an age-related decrease in the effectiveness of adrenergic stimulation. Studies employing beta-adrenergic agonists and antagonists in both man and animals provide support for this hypothesis. In addition, a postsynaptic decrement in sympathetic responsiveness is indicated from in vitro studies in both cardiac and vascular tissue. However, while a strong case for diminished adrenergic responsiveness of the aged cardiovascular system can be made from these data, further information at both the tissue and the organismal level is required to fully elucidate the nature of this age-related decline.