Venous pressure dynamics of the healthy human leg - Role of muscle activity, joint mobility and anthropometric factors

The delicate interplay between the muscle-joint unit and intact venous valv es is mandatory for normal venous blood return from the human leg. We have investigated the potential role of(1) muscle activity and joint mobility, a nd (2) anthropometric factors for peripheral venous pressure physiology. 20 healthy young subjects (10 males, 10 females; mean age: 25.6 +/- 3.1 years ) underwent direct venous blood pressure measurements during walking on a t readmill in 12 experimental conditions (duration, 1 min each): these result ed from a combination of two different walking velocities, two different de grees of ascent, and three different walking conditions. Anthropometric par ameters (e.g., body height, weight and calf circumference) were also measur ed in all subjects. Outcome measures were the pressures (mm Hg) du ring qui et standing (resting pressure, P-0), the maximal activity-induced pressure reduction (DeltaP(max)), i.e., the difference between the resting pressure (P-0) and minimal pressure during exercise (P-min), the times (s) to minima l pressure during exercise (T-Pmin) and to half-maximal recovery of P-0 aft er exercise (T-max1/2) We found that the maximal venous pressure reduction (DeltaP(max)) during walking increased at the higher walking speed and decr eased with restricted joint mobility (p = 0.0001). Taller and heavier subje cts, or subjects with a greater calf circumference had higher P-0 (p = 0.00 01), showed greater DeltaP(max) (p < 0.010), and took longer to achieve min imal pressure during exercise (TPmin; p < 0.010) than their corresponding c ounterparts. Females had lower levels of P-0 (p = 0.0001), but not of Delta P(max), and shorter T-Pmin (p = 0.0076) than males. These gender effects la rgely result from differences in body height, weight, and calf circumferenc e (p = 0.0001 for the appropriate ANOVA interaction terms). We conclude tha t during walking, a higher degree of muscle activity and a greater muscle m ass enhance venous emptying of the healthy human leg. Conversely, impairmen ts of joint mobility reduce the efficacy of the muscle-vein pump. Moreover, body height and weight significantly influence venous pressure physiology under both resting and activity-related conditions. These anthropometric fa ctors also largely explain sex differences in peripheral venous hemodynamic s. Copyright (C) 2001 S. Karger AG, Basel.