Calf Venous Compliance Differences in Male and Female Adults

Abstract

Similar to changes in arterial compliance with fitness and aging, venous compliance in the lower extremities of adults improves with higher fitness and declines with increasing age. In young adults, males have a higher venous compliance than females, a difference that does not appear related to hormonal fluctuations. Most previous studies have used small groups to make these comparisons. PURPOSE: To determine the calf venous compliance differences in males and females in a larger group of adults. METHODS: 71 females and 102 males volunteered for this project. Participants underwent anthropometric assessment, a submaximal graded exercise test, and assessment of calf venous compliance. Utilizing venous occlusion plethysmography, calf pressure-volume relations were determined using the quadratic regression equation [(Δlimb volume) = β0 + β1*(cuff pressure) + β2*(cuff pressure)2]. Calf venous compliance was calculated as the first derivative of the pressure-volume relation during cuff pressure reduction. Sex differences in anthropometric variables, fitness, and compliance (β1, β2, and the slope of the pressure compliance relationship) were analyzed with a simple ANOVA. RESULTS: The males and females were of similar age [102 males (26 ± 12 yrs), 71 females (28 ± 17 yrs)] and fitness level (males 50.24 ± 19.55 ml*kg−1*min−1 vs. females 47.84 ± 16.03 ml*kg−1*min−1). The males were larger in size (BMI: 25.07 ± 3.81 kg/m2; calf volume: 585.79 ± 116.70 cm) than the females (BMI: 23.78 ± 4.3 kg/m2; calf volume: 497.52 ± 132.31 cm). Females had significantly larger β0 values than males, but males had significantly higher β2 values than females indicating higher calf venous compliance [males; ΔLimb Volume = 0.6665 ± 1.89051 + 0.0939 ± 0.1119 (Cuff Pressure) - 0.0212 ± 0.20587 (Cuff Pressure)2 vs. females; ΔLimb Volume = 1.8384 ± 5.28027 + 0.1083 ± 0.12568 (Cuff Pressure) - 0.0009 ± 0.00107). Compliance @ 20mmHg was significantly higher in males than females (0.28 ± 0.83mmHg vs. 0.06 ± 0.02 mmHg respectively). CONCLUSION: Consistent with previous research, this large data set found males to have higher calf venous compliance than females and females to have higher net capillary filtration than males.