Sex differences in the effects of type 2 diabetes on exercise performance

Area of Science:

• Cardiology
• Endocrinology
• Exercise Physiology

Background:

• Type 2 diabetes (T2D) is associated with impaired exercise performance and cardiovascular abnormalities.
• Women with T2D experience worse cardiovascular (CV) outcomes compared to men with T2D.

Purpose of the Study:

• To investigate sex differences in exercise impairment in individuals with uncomplicated T2D.
• To determine if women with T2D exhibit a greater exercise deficit compared to men with T2D, relative to their non-diabetic counterparts.

Main Methods:

• Cross-sectional study involving premenopausal women and men with T2D and their non-diabetic controls.
• Comprehensive exercise testing, including peak oxygen consumption (V˙O2peak) and V˙O2 kinetics.
• Assessment of insulin sensitivity, endothelial function, blood flow, and resting cardiac function.

Main Results:

• Both men and women with T2D had impaired insulin sensitivity compared to controls.
• Women with T2D demonstrated a significantly greater reduction in V˙O2peak (24%) compared to men with T2D (16%) relative to controls (P < 0.05 between sexes).
• Women with T2D showed impaired endothelial function (flow-mediated dilation) and blood flow responses, while men with T2D had impaired flow-mediated dilation but preserved blood flow responses.

Conclusions:

• Exercise capacity is reduced in both sexes with T2D, but the impairment is more pronounced in women.
• The greater exercise limitation in women with T2D, linked to V˙O2peak and cardiovascular function, may underlie their increased risk of CV morbidity and mortality.