We examined hemodynamic and autonomic components of blood pressure
responses during active and passive stressor tasks in a sample
of young, normotensive men and women who were physically active
but differed on fitness (i.e., [V below dot]O2peak).
During the hand cold pressor, increases in systolic blood pressure
were inversely related to fitness among women but not men.
Regardless of gender, fitter participants had a greater increase
in cardiac pace during mental arithmetic, coherent with a decreased
cardiac-vagal component of heart rate variability, and a greater
compensatory reduction in stroke volume. Fitness was otherwise
unrelated to changes in cardiac output and vascular resistance
during the stressor tasks. Our findings suggest that
cardiorespiratory fitness augments the cardiac-vagal withdrawal
that is characteristic of mental arithmetic. The blunted systolic
blood pressure response to the hand cold pressor among fitter
women suggests that cardiorespiratory fitness should be considered
as a covariate in studies that examine the hand cold pressor
as a predictor of future hypertension among women.