Rapid onset pressor response to exercise in young women with a family history of hypertension.

Abstract

What is the central question of this study? Alterations in blood pressure control at exercise onset are apparent in older adults with established cardiovascular disease. It is currently not known whether these alterations are evident in young adults with a family history of hypertension. What is the main finding and its importance? We demonstrate that young women with a family history of hypertension display a larger change in blood pressure within the first 10s of isometric exercise. These data suggest altered blood pressure control in young women with a family history of hypertension. Hypertensive adults demonstrate atypical increases in blood pressure (BP) and muscle sympathetic nerve activity (MSNA) at the immediate onset of static muscle contraction. However, it is unknown whether these abnormal responses occur in young, otherwise healthy adults at risk for developing future disease, such as those with a family history of hypertension (+FH). We tested the hypothesis that +FH young women have exaggerated increases in BP and MSNA at the onset of static muscle contraction compared with those without a family history of hypertension (-FH). We retrospectively examined beat-by-beat BP and MSNA during the initial 30s of isometric handgrip exercise (30% of maximal voluntary contraction) in 16 +FH (22±2years old, 22±3kgm-2 ) and 16 -FH (22±3years old, 22±3kgm-2 ) women. Resting mean arterial pressure (+FH 80±11mmHg versus -FH 84±13mmHg), MSNA burst frequency (+FH 7±3burstsmin-1 versus -FH 9±5burstsmin-1 ) and burst incidence [+FH 12±4 bursts (100heart beats)-1 versus -FH 12±8bursts (100heart beats)-1 ] were similar between groups (all P>0.05). Within the first 10s of exercise, changes in mean arterial pressure (+FH Δ8±6mmHg versus -FH Δ3±2mmHg, P<0.05) and heart rate (+FH Δ8±5beatsmin-1 versus -FH Δ4±4beatsmin-1 , P<0.05) were greater in +FH women. Absolute MSNA burst frequency during the first 30s of exercise was not different between groups (-FH 7±5burstsmin-1 versus +FH 9±3burstsmin-1 ). Cardiovascular and sympathetic responses during the cold pressor test were not different between groups. These data demonstrate that young women at risk for developing cardiovascular disease exhibit greater changes in BP at the onset of static muscle contraction.