Physical training, vegetative regulation, and cardiac hypertrophy

Area of Science:

• Cardiovascular Physiology
• Exercise Science
• Sports Medicine

Background:

• Dynamic physical training induces significant functional and structural adaptations in the cardiovascular system.
• Functional changes, such as resting bradycardia, precede structural alterations and are linked to autonomic nervous system modulation.

Purpose of the Study:

• To explore the functional and structural adaptations of the cardiovascular system in response to dynamic physical training.
• To investigate the role of autonomic tone and receptor changes in training-induced cardiac modifications.
• To compare the characteristics of training-induced cardiac hypertrophy with pathological hypertrophy.

Main Methods:

• Analysis of functional cardiovascular changes (e.g., heart rate, stroke volume) in trained individuals.
• Examination of structural adaptations, including left ventricular muscle mass (LVM) and dimensions.
• Assessment of myocardial responsiveness and autonomic nervous system activity.

Main Results:

• Early functional changes like bradycardia occur before significant structural changes (hypertrophy).
• Training influences beta- and alpha-receptor density and responsiveness, affecting sympathetic activity.
• Training-induced cardiac hypertrophy results in enlarged ventricles, increased stroke volume, and preserved ejection fraction, with a constant mass/volume ratio and wall stress.

Conclusions:

• Functional cardiovascular adaptations to training, including enhanced stroke volume, are established early and are maintained or intensified with cardiac hypertrophy.
• The trained heart exhibits improved capacity for stroke volume augmentation during exercise compared to normal or pathologically hypertrophied hearts.
• Autonomic modulation and receptor alterations play crucial roles in the cardiovascular adaptations observed with endurance training.