Blood volume expansion among blacks: An hypothesis

Schachter, Joseph; Kuller, Lewis H.

doi:10.1016/0306-9877(84)90057-4

Cited by 11 publications

(4 citation statements)

References 101 publications

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“…Normotensive blacks demonstrate a blunted natriuresis following NaCl loading (50,51) and a higher sensitivity in BP response to NaCl (51,52). These findings coupled with demonstrations of lower PRA in blacks vs. whites (10, 51, 53, 54) suggest a relatively expanded extracellular fluid volume in blacks vs. whites (55). Furthermore, the decrease in urinary K' excretion in blacks noted by us and others (10, 56) could be due to a decrease in K+ intake (10, 57), though a lower renal Na+-K+-ATPase activity (58,59) can be an additional factor responsible for this finding.…”

Section: Discussionmentioning

confidence: 72%

Race and sex differences in erythrocyte Na+, K+, and Na+-K+-adenosine triphosphatase.

Lasker¹,

Hopp²,

Grossman³

et al. 1985

J. Clin. Invest.

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Several reports indicate that erythrocytes (RBCs) from blacks and men have higher sodium concentrations than those from whites and women. One possible mechanism to explain this finding is a difference in the activity of Na'-K+-ATPase. To explore this possibility, we have studied the Na' And K+ kinetics of RBC Na'-K+-ATPase and RBC Na' and KV concentrations in 37 normotensive blacks and whites, both males and females. The maximal initial reaction velocity (V..,[) values for RBC Na'-K+-ATPase were lower in blacks and men as compared with whites and women. Higher RBC Na+ levels were observed in blacks and males vs. whites and females. Significant inverse correlations were noted between the Na+-K+-ATPase activity and RBC Na+ concentrations. These findings indicate that cellular Na+ homeostasis is different in blacks and men as compared with whites and women. Since higher RBC Na+ concentrations have also been observed in patients with essential hypertension as compared with normotensive subjects, the higher intracellular Na' concentrations in blacks and men may contribute to the greater predisposition of these groups to essential hypertension.

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Section: Discussionmentioning

confidence: 72%

Race and sex differences in erythrocyte Na+, K+, and Na+-K+-adenosine triphosphatase.

Lasker¹,

Hopp²,

Grossman³

et al. 1985

J. Clin. Invest.

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“…This has puzzled investigators since previous studies have reported a sympathetic predominance in early hypertension (Pieper, & Hammill, 1995;Takalo, Korhonen, Turjanmaa, Majahalme, Tuomisto, & Uusitalo, 1994) and there is a higher prevalence of hypertension in the African American population (Hypertension Detection and Follow-up Program Cooperative Group, 1979). Although there is no clear explanation for these findings, it may be that the lower sympathetic activity in African Americans is a consequence of an elevated plasma volume of renal origin (Gillum, 1979;Schachter, & Kuller, 1984).…”

Section: Mitigating Factors Of Autonomic Regulationmentioning

confidence: 99%

Influence of Short-Term Endurance Exercise Training on Heart Rate Variability

Lee¹,

Wood²,

Welsch³

2002

Medicine & Science in Sports & Exercise

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The purpose of this investigation was to determine if 8 exercise endurance training (ET) sessions over 2 weeks significantly alters cardiac autonomic modulation, as measured by heart rate variability (HRV). Twenty-four college-aged males were recruited for this study and were randomized into either an exercise group (EX; n=12) or a control group (CT; n=12). EX underwent 2 weeks of ET on a cycle-ergometer (frequency: four times/week; duration: 40 minutes; intensity 80-85% HR reserve), whereas CT was instructed not to alter their previous level of physical activity. Five-minute ECG tracings were collected for HRV under the following conditions: 5 minutes of paced breathing at a frequency of 12 breaths/minute (PB), 5 minutes of spontaneous breathing (SB1), 5 minutes of 70-degree head-up tilt on a tilt table (TILT), and a second 5-minute period of spontaneous breathing (SB2). The data were collected on 5 occasions (Test 1-Test 5) during a 2-week period. HRV was reported as the standard deviation of RR intervals, and as normalized units (NU) of the natural logarithm of high-and low-frequency power (lnHF and lnLF). A mixed-model analysis of variance (ANOVA) with repeated measures was used to evaluate any Group X Time interaction, or main effects of Group or Time on HRV. Alpha was set at 0.05. EX exhibited a significant increase in peak oxygen consumption (8%), whereas this parameter was unchanged in CT. During PB, ANOVA revealed a Group X Time interaction such that EX exhibited decreases in lnLFNU (2.89 vs. 3.45 ln%) and lnLF/lnHF (0.82 vs. 0.90) during Test 5 compared to Test 1, while there were no such differences across time in CT. Additionally, there was a Group X Time interaction during TILT such that EX exhibited lower lnLFNU (4.12 vs. 4.42 ln%) and lnLF/lnHF (1.12 vs. 1.46), and greater lnHFNU (3.52 vs. 2.53 ln%) during Test 5 compared to Test 1, while these indices were unchanged across time in CT. These data suggest that 8 ET vii sessions over 2 weeks increases vagal modulation of the heart. Furthermore, these data suggest that it takes at least 8 ET sessions to induce such changes.

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“…No data are available about differences in blood volume among ethnic groups. Schachter and Kuller (1984) discussed the hypothesis of blood volume expansion in Blacks. These authors indicated that an important reason for acceptance of the hypothesis of blood volume expansion in Black hypertensives is based on the fact that diuretics are more effective antihypertensive agents in Blacks than in Whites.…”

Section: Discussionmentioning

confidence: 99%

Ethnic Differences in Physiological Responses Associated with the Valsalva Maneuver

Metzger

Therrien

1990

Research in Nursing & Health

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Ethnic differences in cardiovascular indices at rest and across the Valsalva maneuver (VM) were studied in 30 Asian, 86 Caucasian, and 12 Black healthy men and women aged 30 to 55 years. Subjects simulated the VM by blowing into an aneroid pressure-gauge meter to 40 mmHg for 10 seconds. Resting systolic blood pressure (SBP) was significantly higher in Blacks than in Asians or Caucasians. During the strain phase of the VM, the fall in SBP from baseline was significantly greater in Asians and Blacks than in Caucasians. Further, Asians had the greatest overshoot of SBP above baseline. Although resting heart rate was significantly higher in Asians compared to Caucasians, there were no differences in heart rate responses to the VM. Reduction in carotid artery blood flow velocity during strain was significantly less in Blacks. We conclude that there are ethnic differences in cardiovascular indices at rest and across the VM.

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Blood volume expansion among blacks: An hypothesis

Cited by 11 publications

References 101 publications

Race and sex differences in erythrocyte Na+, K+, and Na+-K+-adenosine triphosphatase.

Race and sex differences in erythrocyte Na+, K+, and Na+-K+-adenosine triphosphatase.

Influence of Short-Term Endurance Exercise Training on Heart Rate Variability

Ethnic Differences in Physiological Responses Associated with the Valsalva Maneuver

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