Increased Hematocrit with Normal Red Blood Cell Mass in Early Borderline Essential Hypertension

Lebel, Marcel; Grose, John H.; Blais, R.

doi:10.3109/10641968909038179

Cited by 12 publications

(16 citation statements)

References 21 publications

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“…7 Therefore, other possible pathogenic factors for low PV may be more likely such as a constitutionally small venous compartment 18 or a constricted venous system. 27,28 Both glomerular hyperfiltration and a constricted venous system are linked to sympathetic overactivity. 26,27 Our results are consistent with a constricted, but not necessarily constitutionally small, venous compartment.…”

Section: Discussionmentioning

confidence: 99%

“…27,28 Both glomerular hyperfiltration and a constricted venous system are linked to sympathetic overactivity. 26,27 Our results are consistent with a constricted, but not necessarily constitutionally small, venous compartment. 29,30 A constitutionally small venous compartment most likely would have resulted in a small increase in PV with training in formerly PE women, yet our data show that PV increased at least as much in formerly PE women as in controls.…”

Section: Discussionmentioning

confidence: 99%

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Aerobic Exercise Training in Formerly Preeclamptic Women

et al. 2015

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Women with a history of preeclampsia are at increased risk of recurrent gestational hypertensive disease and cardiovascular disease later in life.1,2 Fifty percent of formerly preeclamptic women (formerly PE women) have low plasma volume (PV) 3 and the recurrence risk of preeclampsia varies inversely with PV. 4 In pregnancy, a marked PV expansion (+30% to 60%) is required to meet the physiological demands of advanced pregnancy. 5,6 Formerly PE women with low PV show reduced PV expansion in pregnancy, which suggests that the adaptive capacity of the venous system in these women is limited.7 When PV expansion cannot meet the physiological demands, the circulation may compensate for it by an increase in sympathetic activity. 7 The resulting lowvolume high-output circulation will exert extra shear stress on the endothelium. 3,7 This may set the stage for endothelial dysfunction, vascular damage, and hypertensive disease in pregnancy and later in life.The venous compartment is the most prominent blood volume reservoir of the body. Although at rest two-thirds of PV is localized in the venous system, it can be rapidly mobilized by sympathetic-mediated venoconstriction in times of increased arterial demands, including pregnancy and exercise. 8,9 Venous capacity is largely determined by venous compliance (VeC) and varies dynamically with sympathetic tone predominantly controlled by the baroreflex system. 8 Dynamic changes in VeC can be tested through orthostatic stress testing. Previous studies demonstrated that formerly PE women at rest have low venous reserve, characterized by low PV, low VeC, and high sympathetic tone. 10Aerobic exercise is perhaps the best intervention to improve venous reserve. It increases PV and reduces sympathetic tone in healthy individuals. 11,12 In formerly PE women with low PV, aerobic exercise training could help to normalize venous reserve and thereby reduce the risk of hypertensive disease in future pregnancy and later in life. The extent to which formerly PE women are able to improve their venous reserve by exercise training is unknown. Our study addresses the question to what extent an aerobic exercise training program Abstract-In women with a history of preeclampsia, low plasma volume (≤1373 mL/m 2 ) is associated with recurrent preeclampsia and chronic hypertension. Interventions that improve volume reserve may reduce these risks in formerly preeclamptic women. In this study, we examined the effects of aerobic exercise training on venous reserves in 24 normotensive formerly preeclamptic women and 20 controls. Before and after 12-week aerobic exercise training, we measured plasma volume with albumin indicator dilution technique and venous compliance with venous occlusion plethysmography. Venous compliance and hemodynamic responses were assessed dynamically during graded head-up tilt (HUT). Formerly preeclamptic women had lower pretraining plasma volume and venous compliance than controls (1348±78 versus 1529±112 mL/m ; P<0.01, respectively). Blood pressure decreased comparably between...

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Aerobic Exercise Training in Formerly Preeclamptic Women

et al. 2015

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“…This group of women is reported to exhibit latent hemodynamic abnormalities consistent with the early stages of chronic hypertension, like low PV, low VeC, and higher sympathetic tone. 3,31,32 The increase in PV and VeC in response to physical exercise is relatively high in our study group. It is tempting to speculate that these correcting cardiovascular effects may reduce the risk of recurrent hypertensive disease in a subsequent pregnancy and remotely the risk of cardiovascular disease in later life.…”

Section: Discussionmentioning

confidence: 85%

“…We included 9 normotensive nonpregnant formerly preeclamptic women with a median age of 34 (31)(32)(33)(34)(35)(36)(37) …”

Section: Resultsmentioning

confidence: 99%

Exercise-induced Changes in Venous Vascular Function in Nonpregnant Formerly Preeclamptic Women

et al. 2009

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Objective: Formerly preeclamptic women with low plasma volume are at increased risk of recurrent gestational hypertensive disease. We hypothesized that a 4-week cycling training in formerly preeclamptic women improves (venous) hemodynamic function. Methods: In 9 formerly preeclamptic women, we examined physical fitness and hemodynamic function, before and after the training.We assessed blood pressure, heart rate, cardiac output, plasma volume, and calf and forearm venous compliance. Results: After the training, baseline blood pressure and cardiac output remained unchanged, but resting heart rate decreased (-7%, P ¼ .02). Plasma volume was 8% higher after training (P ¼ .01). Calf venous compliance increased (þ18%, P ¼ .02) but not forearm venous compliance (þ14%, P ¼ .09). Conclusion: Cycling training improves venous vascular function in formerly preeclamptic women. The decreased resting heart rate and improvement of venous compliance suggest reduced sympathetic activity. These rapid exercise-induced changes may improve maternal vascular adaptation in early pregnancy and with it the risk of (recurrent) gestational hypertensive disease.

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“…Instead plasma is displaced from the intravascular to the interstitial space [51]. Furthermore, men with severe [52] and early borderline [53] essential hypertension have a stable red cell mass, indicating that the increased hematocrit among those with essential hypertension is likely due to a contracted plasma volume. However, one must bear in mind that the direction of causality between hypertension and hemoconcentration state cannot be determined on the basis of such observational studies.…”

Section: Hemoconcentration and Coronary Heart Diseasementioning

confidence: 99%