Background: Blood pressure and total peripheral resistance increase with age. However, the effect of age on vasodilatory capacity has not been characterized.
Methods and results: To delineate the effects of aging, gender, and physical training on peripheral vascular function, we measured blood pressure during submaximal and maximal treadmill exercise and measured blood pressure, calf blood flow, and calf conductance (blood flow/mean blood pressure) at rest and during maximal hyperemia in 58 healthy sedentary subjects (men aged 25 +/- 5 and 65 +/- 3 years and women aged 27 +/- 5 and 65 +/- 4 years) and in 52 endurance exercise-trained subjects (men aged 30 +/- 3 and 65 +/- 4 years and women aged 27 +/- 3 and 65 +/- 3 years). Systolic and mean blood pressures were higher at rest, during maximal calf hyperemia, and during submaximal exercise of the same intensity in the older than in the younger subjects of the same gender and exercise training status (p less than 0.01). The magnitude of the age-related effect on blood pressure during exercise was greater in women than in men (p less than 0.01). Diastolic blood pressure during submaximal exercise was also higher in the older than in the younger subjects (p less than 0.05) but not in women treated with estrogen replacement. In contrast, systolic and mean blood pressures during submaximal work were lower in physically conditioned subjects than in sedentary age- and gender-matched subjects (p less than 0.05) but not in older women. Increased age was associated with reduced maximal calf conductance in women (p less than 0.01) but not in men. However, calf vasodilatory capacity was higher in trained than in untrained subjects (p less than 0.01), regardless of age and gender. There was a significant inverse relation between maximal calf conductance and systolic, diastolic, and mean blood pressures during submaximal exercise (r = -0.31 to -0.53, p less than 0.01) and a direct relation between maximal calf conductance and maximal oxygen uptake (r = 0.66, p less than 0.0001).
Conclusions: Thus, for healthy subjects between the ages of 25 and 65 years, there is an interactive effect between age and gender and an independent effect of physical training on peripheral vascular function.