title: Sex differences in leg vasodilation during graded knee extensor exercise in young adults.
abstract: Limb vascular conductance responses to pharmacological and nonexercise vasodilator stimuli are generally augmented in women compared with men. In the present investigation, we tested the hypothesis that exercise-induced vasodilator responses are also greater in women than men. Sixteen women and 15 men (20-30 yr) with similar fitness and activity levels performed graded quadriceps exercise (supine, single-leg knee extensions, 40 contractions/min) to maximal exertion. Active limb hemodynamics (left common femoral artery diameter and volumetric blood flow), heart rate (ECG), and beat-to-beat mean arterial blood pressure (MAP; radial artery tonometry) were measured during each 3-min workload (4.8 and 8 W/stage for women and men, respectively). The hyperemic response to exercise (slope of femoral blood flow vs. workload) was greater (P < 0.01) in women as was femoral blood flow at workloads >15 W. The leg vasodilatory response to exercise (slope of calculated femoral vascular conductance vs. absolute workload) was also greater in women than in men (P < 0.01) because of the sex difference in hyperemia and the women's lower MAP ( approximately 10-15 mmHg) at all workloads (P < 0.05). The femoral artery dilated to a significantly greater extent in the women ( approximately 0.5 mm) than in the men ( approximately 0.1 mm) across all submaximal workloads. At maximal exertion, femoral vascular conductance was lower in the men (men, 18.0 +/- 0.6 ml.min(-1)xmmHg(-1); women, 22.6 +/- 1.4 mlxmin(-1)xmmHg(-1); P < 0.01). Collectively, these findings suggest that the vasodilatory response to dynamic leg exercise is greater in young women vs. men.
authors: Dept. of Kinesiology, The Pennsylvania State Univ., 105 Noll Laboratory, Univ. Park, PA 16802-6900, USA.
authors: Beth A
authors: BA
authors: Parker
authors: Sandra L
authors: SL
authors: Smithmyer
authors: Justin A
authors: JA
authors: Pelberg
authors: Aaron D
authors: AD
authors: Mishkin
authors: Michael D
authors: MD
authors: Herr
authors: David N
authors: DN
authors: Proctor
mesh_terms: D000328:Adult; D001783:Blood Flow Velocity; D001794:Blood Pressure; D004576:Electromyography; D015444:Exercise / Q000502:physiology*; D005260:Female; D005263:Femoral Artery / Q000000981:diagnostic imaging / Q000502:physiology*; D006339:Heart Rate; D006801:Humans; D007717:Knee / Q000502:physiology*; D007866:Leg / Q000098:blood supply*; D008297:Male; D009119:Muscle Contraction; D052097:Quadriceps Muscle / Q000098:blood supply* / Q000502:physiology; D012039:Regional Blood Flow; D012737:Sex Factors; D018616:Ultrasonography, Doppler, Duplex; D014664:Vasodilation