Age and regional specificity of peak limb vascular conductance in women

Abstract

The influence of age on limb vasodilator capacity in women is unclear. The objectives of this study were to characterize and compare age-associated changes in forearm and calf peak vascular conductance (VC(peak); a functional index of arterial structure) in women and to identify physiological characteristics predictive of variation in limb-specific VC(peak). Peak conductance (plethysmographic flow/mean arterial pressure), VC(peak) of the forearm (forearm VC(peak)), and calf (calf VC(peak)) after 10 min of arterial occlusion were measured in 58 healthy, normally active women aged 21-79 yr. Aerobic capacity (cycle peak oxygen uptake), arterial health (pulse-wave velocity, ankle-brachial index), total cholesterol, limb-specific tissue composition (dual-energy X-ray absorptiometry), and isometric strength (handgrip, plantar flexion) were also assessed. The relative decline in calf VC(peak) with age (-6.8% per decade, P < 0.001) was greater than the forearm (-4.4% per decade, P = 0.004), in contrast to results previously reported for men (forearm decline > calf decline). Limb VC(peak) per kilogram muscle declined with age in the calf (-6.0% per decade; P = 0.002), but not the forearm (P = 0.12). Age, cholesterol, and regional tissue composition were significant predictors of peak conductance in both limbs; however, age was a stronger predictor of peak conductance in the calf. These results suggest that healthy aging is associated with a linear decline in limb vasodilator capacity in women, but the magnitude of this effect is region specific. Further research will be required to determine whether the decline in lower extremity vasodilator capacity with age explains diminished exercising leg vasodilation in older women.

Sex-specific effect of aging on submaximal leg exercise hemodynamics in middle-aged and older adults

“…1, 2). This observation is in agreement with previous findings that the relationship between age and peak forearm vasodilation evoked by cuff occlusion is stronger in men than women Ridout et al 2005;Hodges et al 2010). However, normalization to estimated quadriceps mass abolished the age effect for both leg hemodynamic outcomes in men, a finding that is in agreement with previous comparisons between normally active young and older men at similar absolute workloads during knee-extensor exercise (Donato et al 2006;Parker et al 2008).…”

“…Data from the current study provide evidence that indeed factors besides age influence exercising leg hemodynamics as the multivariate model r 2 was significantly improved when additional characteristics besides age were added into the model (Table 2). Consequently, another finding of the current study is that there is sex specificity in the determinants of leg hyperemia, in agreement with reported sex differences in the predictors of peak calf conductance Ridout et al 2005). In men, the strongest predictors of exercising leg vascular conductance were BMI and lower extremity strength (represented by any isometric or isokinetic strength variable of the dominant leg), which were inversely and positively associated with conductance, respectively.…”

Relationship between leg muscle capillary density and peak hyperemic blood flow with endurance capacity in peripheral artery disease

“…Although many previous reports (3, 4, 37) have detected a difference between these groups, careful inspection of these studies demonstrate that age is rarely statistically taken into account. It has been reported that peak hyperemic flow is reduced with age (27,30,33), which could explain why the difference between groups is no longer significant after age is considered. In addition, Ogren et al (28) reported that 76% of IC patients in his study had normal peak hyperemic flow.…”

Limb-specific differences in the skin vascular responsiveness to adrenergic agonists

“…Because the forearm has been exclusively used as a model for studying vascular function, it has become common to extrapolate the findings obtained from this vascular bed to the rest of the body. However, the heterogeneity between the upper and lower limbs in adrenoceptor-mediated control in both muscle and skin blood flow should be considered in the evaluation of vascular function, because morphophysiological changes in the forearm vasculature resulting from a pathological state or aging do not always parallel those observed in the lower extremities (27,28,32).…”