Evaluation of cardiovascular autonomic function tests in normal subjects

Area of Science:

• Cardiovascular Physiology
• Autonomic Nervous System Function
• Noninvasive Physiological Measurement

Background:

• Autonomic nervous system (ANS) regulates involuntary functions.
• Assessing ANS function is crucial for understanding cardiovascular health.
• Noninvasive cardiovascular reflex tests offer a safe method for ANS evaluation.

Purpose of the Study:

• To evaluate autonomic function in healthy adults using noninvasive cardiovascular reflex tests.
• To determine the influence of age and sex on autonomic test results.
• To establish reference ranges for autonomic function tests in a healthy population.

Main Methods:

• Seventy-six healthy adults (20-80 years) underwent noninvasive cardiovascular reflex tests.
• Tests included heart rate and blood pressure responses to standing, Valsalva maneuver, deep breathing, diving, cold immersion, and handgrip.
• Electrocardiogram (EKG) monitoring was used throughout the resting state tests.

Main Results:

• Heart rate responses to standing, Valsalva, and deep breathing showed low variability, indicating suitability for follow-up.
• Sex differences observed: women had greater systolic BP drop upon standing and less diastolic BP rise during handgrip.
• Age negatively correlated with heart rate responses and positively with systolic BP fall upon standing in women.

Conclusions:

• Sex and age significantly impact autonomic function test outcomes.
• Sex differences are more associated with sympathetic function, while age affects both sympathetic and parasympathetic systems.
• Proposed normal ranges for autonomic function tests in healthy subjects provide a valuable reference.