Cardiac dimension changes with endurance training. Indications of a genotype dependency

Area of Science:

• Exercise Physiology
• Cardiovascular Adaptation
• Genetics

Background:

• Understanding the impact of endurance training on cardiac structures is crucial for optimizing athletic performance and cardiovascular health.
• Variability in individual responses to training highlights the potential influence of genetic factors.

Purpose of the Study:

• To investigate the sensitivity of cardiac structures to a 20-week endurance training program.
• To evaluate the variability in cardiac adaptation to endurance training between sedentary individuals and monozygotic twins.
• To explore the potential role of genotype in modulating cardiac responses to endurance exercise.

Main Methods:

• A 20-week controlled endurance training program was administered to 20 sedentary subjects and 10 pairs of monozygotic twins.
• Maximal oxygen uptake (VO2 max) was measured to assess training response.
• Cardiac dimensions, including left ventricular diameter, wall thickness, end-diastolic volume, and mass, were assessed.

Main Results:

• Maximal oxygen uptake significantly increased in both groups, with a larger relative increase in sedentary subjects (30%) compared to twins (13%).
• Sedentary subjects showed significant increases in left ventricular diameter, posterior wall and septal thicknesses, end-diastolic volume, and left ventricular mass.
• Monoygotic twins did not exhibit significant changes in these cardiac dimensions, and their inter-individual differences increased post-training, while within-pair resemblance also increased.

Conclusions:

• Cardiac dimensions are significantly modifiable by endurance training in sedentary individuals.
• The extent and variability of cardiac adaptation to endurance training appear to be influenced by genetic factors (genotype-dependent).
• Endurance training may lead to greater divergence in cardiac morphology between genetically similar individuals over time.