Baroreflex function and cardiac structure with moderate endurance training in normotensive men

Area of Science:

• Cardiovascular Physiology
• Exercise Physiology
• Autonomic Nervous System Function

Background:

• Understanding how moderate endurance training impacts autonomic cardiovascular regulation is crucial for public health.
• Baroreflex sensitivity is a key indicator of cardiovascular health and adaptability.

Purpose of the Study:

• To investigate the effects of 10 weeks of moderate endurance training on arterial and cardiopulmonary baroreflex function in sedentary men.
• To assess changes in cardiac structure in response to the training intervention.

Main Methods:

• Sedentary normotensive men (22-34 yr) were randomized into an exercise training (ET) group or a control (UT) group.
• The ET group underwent 10 weeks of moderate cycling (60 min, 3 days/wk, 60% VO2max).
• Arterial and cardiopulmonary baroreflex function, cardiac structure, and maximal oxygen uptake (VO2max) were assessed before and after the intervention.

Main Results:

• Exercise training led to decreased resting heart rate and mean arterial pressure, and increased VO2max.
• A significant increase in the gain of the spontaneous baroreflex response at rest was observed in the ET group.
• No significant changes were found in carotid-cardiac baroreflex function over the full range, cardiopulmonary baroreflex function, or cardiac structure.

Conclusions:

• Moderate endurance exercise training enhances the spontaneous baroreflex, improving heart rate regulation during normal arterial pressure fluctuations.
• These improvements occur independently of changes in overall baroreflex curves, cardiopulmonary reflexes, or cardiac morphology.
• This suggests a specific adaptation in the sympathetic-vagal balance regulating heart rate in response to exercise training.