Blood pressure responses to handgrip exercise but not apnea or mental stress are enhanced in women with a recent history of preeclampsia

Abstract

Preeclampsia is a risk factor for future cardiovascular diseases. However, the mechanisms underlying this association remain unclear, limiting effective prevention strategies. Blood pressure responses to acute stimuli may reveal cardiovascular dysfunction not apparent at rest, identifying individuals at elevated cardiovascular risk. Therefore, we compared blood pressure responsiveness with acute stimuli between previously preeclamptic (PPE) women (34 ± 5 yr old, 13 ± 6 mo postpartum) and women following healthy pregnancies (Ctrl; 29 ± 3 yr old, 15 ± 4 mo postpartum). Blood pressure (finger photoplethysmography calibrated to manual sphygmomanometry-derived values; PPE: n = 12, Ctrl: n = 12) was assessed during end-expiratory apnea, mental stress, and isometric handgrip exercise protocols. Integrated muscle sympathetic nerve activity (MSNA) was assessed in a subset of participants (peroneal nerve microneurography; PPE: n = 6, Ctrl: n = 8). Across all protocols, systolic blood pressure (SBP) was higher in PPE than Ctrl (main effects of group all P < 0.05). Peak changes in SBP were stressor specific: peak increases in SBP were not different between PPE and Ctrl during apnea (8 ± 6 vs. 6 ± 5 mmHg, P = 0.32) or mental stress (9 ± 5 vs. 4 ± 7 mmHg, P = 0.06). However, peak exercise-induced increases in SBP were greater in PPE than Ctrl (11 ± 5 vs. 7 ± 7 mmHg, P = 0.04). MSNA was higher in PPE than Ctrl across all protocols (main effects of group all P < 0.05), and increases in peak MSNA were greater in PPE than Ctrl during apnea (44 ± 6 vs. 27 ± 14 burst/100 hb, P = 0.04) and exercise (25 ± 8 vs. 13 ± 11 burst/100 hb, P = 0.01) but not different between groups during mental stress (2 ± 3 vs. 0 ± 5 burst/100 hb, P = 0.41). Exaggerated pressor and sympathetic responses to certain stimuli may contribute to the elevated long-term risk for cardiovascular disease in PPE.NEW & NOTEWORTHY Women with recent histories of preeclampsia demonstrated higher systolic blood pressures across sympathoexcitatory stressors relative to controls. Peak systolic blood pressure reactivity was exacerbated in previously preeclamptic women during small muscle-mass exercises, although not during apneic or mental stress stimuli. These findings underscore the importance of assessing blood pressure control during a variety of experimental conditions in previously preeclamptic women to elucidate mechanisms that may contribute to their elevated cardiovascular disease risk.

Keywords: blood pressure; muscle sympathetic nerve activity; postpartum; preeclampsia; pressor responses.

Figure 1.

Blood pressure and muscle sympathetic nerve activity (MSNA) responses during an end-expiratory apnea (APN) protocol in previously preeclamptic women (PPE) and control women (Ctrl). Mean and individual blood pressure and MSNA burst incidence (BI) data are presented. Overall systolic blood pressure (SBP), diastolic blood pressure (DBP), and both absolute and relative changes from baseline (Δ) in MSNA BI were higher in PPE (triangles; n = 12) compared with Ctrl (circles; n = 12). Absolute MSNA BI was higher in PPE compared with Ctrl during the first half of the APN (APN1), the second half of the APN (APN2), as well as during the recovery (Rec) period, but not during the APN baseline (BSL) period. In addition, absolute MSNA BI remained elevated during the Rec period compared with BSL in PPE but returned to BSL levels in Ctrl following the APN. The data were analyzed using two-way ANOVAs and presented as means ± SD. *Significant difference between groups within each time bin. σSignificant difference from BSL within the Ctrl group. †Significant difference from BSL within the PPE group.

Figure 2.

Blood pressure and muscle sympathetic nerve activity (MSNA) responses during a mental stress (MS) protocol in previously preeclamptic women (PPE) and control women (Ctrl). Mean and individual blood pressure and MSNA burst incidence (BI) data are presented. Overall, both absolute and relative changes from baseline (Δ) in systolic blood pressure (SBP) and absolute MSNA BI were higher in PPE (triangles; n = 12) compared with Ctrl (circles; n = 12). However, diastolic blood pressure (DBP) was not different between the groups across the MS protocol. MS1, 1st half of mental stress; MS2, 2nd half of mental stress. The data were analyzed using two-way ANOVAs and presented as means ± SD.

Figure 3.

Time course and magnitude of change in blood pressure and muscle sympathetic nerve activity (MSNA) responses during isometric handgrip (HG) exercise with postexercise cuff occlusion (PECO) in previously preeclamptic women (PPE) and control women (Ctrl). Mean and individual blood pressure and MSNA burst incidence (BI) data during baseline (BSL), HG, PECO, and the recovery (Rec) period are presented. Systolic blood pressure (SBP) was higher in PPE (triangles; n = 12) compared with Ctrl (circles; n = 12) during the 30, 90, and 120 s of the HG protocol, as well as during Rec, with greater increases in SBP (Δ) observed in PPE relative to Ctrl during these time points. Similarly, MSNA BI was higher in PPE (n = 5) compared with Ctrl (n = 7) during the 90 and 120 s of the HG protocol, as well as during Rec, with no difference at BSL. Moreover, PPE demonstrated greater increases in MSNA BI compared with Ctrl during these time points of the HG protocol. Both SBP and MSNA BI remained elevated during Rec compared with BSL in PPE but returned to BSL levels in Ctrl. The data were analyzed using two-way ANOVAs and presented as means ± SD. *Significant difference between groups within each time bin. σSignificant difference from BSL within the Ctrl group. †Significant difference from BSL within the PPE group.