Baroreflex buffering is reduced with age in healthy men

Area of Science:

• Cardiovascular Physiology
• Autonomic Nervous System Function
• Human Aging Research

Background:

• Baroreflex buffering is crucial for maintaining arterial blood pressure homeostasis.
• The impact of healthy, physiological aging on tonic baroreflex buffering in humans remains largely unknown.

Purpose of the Study:

• To investigate the effect of healthy aging on baroreflex buffering in men.
• To explore the relationship between aging, baroreflex buffering, and sympathetic nerve activity.

Main Methods:

• Evaluated baroreflex buffering in young (25 years) and older (65 years) healthy men.
• Measured systolic blood pressure responses to phenylephrine before and during ganglionic blockade (trimethaphan).
• Assessed baroreflex buffering by potentiation of systolic blood pressure responses (BRBbolus and BRBslope).

Main Results:

• Older men exhibited significantly reduced baroreflex buffering (BRBbolus and BRBslope) compared to younger men.
• Reduced baroreflex buffering in older men correlated with increased muscle sympathetic nerve activity.
• Baroreflex buffering was inversely related to systolic blood pressure responses to phenylephrine.

Conclusions:

• Physiological aging in men is associated with a substantial decrease in baroreflex buffering.
• This reduction is linked to elevated basal sympathetic nerve activity and diminished alpha1-adrenergic vascular responsiveness.
• Findings aid in understanding baroreflex changes in older individuals, including those with cardiovascular disease.