Differential effects of sex on adaptive responses of skeletal muscle vasodilation to exercise training in type 2 diabetes

Aims: We tested the hypotheses that exercise training improves the peak and dynamic responses of leg vascular conductance (LVC) in males and females with type 2 diabetes (T2DM). Methods: Forty-one males and females with T2DM were assigned to two training groups and two control groups. Twelve weeks of aerobic/resistance training was performed three times per week, 60–90 min per session. Responses of calf muscle blood flow and systemic arterial pressure during incremental and constant-load (30% maximal voluntary contraction) intermittent plantar-flexion protocols in the supine position were recorded. Results: Training significantly increased peak LVC in males (4.86 ± 1.88 to 6.06 ± 2.06 ml·min⁻¹·mm Hg⁻¹) and females (3.91 ± 1.13 to 5.40 ± 1.38 ml·min⁻¹·mm Hg⁻¹) with no changes in control groups. For dynamic responses, training significantly increased the amplitude of the fast growth phase of LVC (1.81 ± 1.12 to 2.68 ± 1.01 ml·min⁻¹·mm Hg⁻¹) and decreased the time constant of the slow growth phase (43.6 ± 46.4 s to 16.1 14.0 s) in females, but no improvements were observed in control females or in any of the two male groups. Conclusions: These data suggest that training increases the peak vasodilatory response in males and females, whereas the speed of the dynamic response of vasodilation is improved in females but not males.