I - Evaluation of Cardiovascular Autonomic Function in Healthy Individuals.

This first part of the review presents nearly 60 years of experience from our laboratory in standardizing cardiovascular autonomic tests in healthy individuals. The wide range of tests includes pharmacological blockade of both the sympathetic and parasympathetic divisions, baroreflex sensitivity assessment through transient hypertension and hypotension, the Valsalva maneuver, head-up tilt testing, isometric and dynamic exercise, facial immersion in cold water, respiratory sinus arrhythmia, heart rate variability analysis in the frequency domain, and imaging with 123I-metaiodobenzylguanidine. Autonomic function was evaluated based on test responses under baseline conditions in healthy individuals. The analysis also covers physiological adaptations to endurance training and aging, providing a reference framework for identifying autonomic dysfunction involving both parasympathetic and adrenergic components in patients with various pathophysiological conditions, as discussed in the second part of this review.