NOS3 gene polymorphisms and exercise hemodynamics in postmenopausal women

Area of Science:

• Cardiovascular Physiology
• Genetics
• Exercise Science

Background:

• Cardiovascular (CV) hemodynamics are crucial for exercise capacity.
• Nitric oxide synthase 3 (NOS3) gene polymorphisms may influence CV function.
• Menopause is associated with changes in CV health and exercise response.

Purpose of the Study:

• To investigate the association between NOS3 G894T and T-786C polymorphisms and CV hemodynamics during exercise in postmenopausal women.
• To determine if physical activity levels modify these associations.
• To understand the genetic influence on exercise responses in this demographic.

Main Methods:

• Cross-sectional study of sedentary, physically active, and endurance-trained postmenopausal women.
• Measurement of heart rate (HR), blood pressures (SBP, DBP), cardiac output (Q), stroke volume (SV), arteriovenous oxygen difference (a-vO2 diff), and total peripheral resistance (TPR) during graded exercise (40-100% VO2max).
• Genotyping for NOS3 G894T and T-786C polymorphisms using standard methods.

Main Results:

• The NOS3 G894T genotype was not associated with SBP, Q, TPR, or a-vO2 diff.
• NOS3 894T non-carriers exhibited higher submaximal and maximal exercise HR compared to T allele carriers.
• NOS3 894T allele carriers demonstrated higher submaximal exercise SV and a trend towards higher maximal SV compared to 894T non-carriers.
• The NOS3 T-786C genotype showed no significant association with any measured CV hemodynamic parameters.

Conclusions:

• The NOS3 G894T polymorphism is associated with altered heart rate and stroke volume responses during submaximal and maximal exercise in postmenopausal women.
• Physical activity level did not appear to modify the association between NOS3 G894T and exercise hemodynamics.
• The NOS3 T-786C polymorphism does not seem to influence exercise CV hemodynamics in this population.