Family history of hypertension, gender, and cardiovascular responsivity during stress

Sympathetic neural reactivity to mental stress in offspring of hypertensive parents: 20 years revisited

A number of recent studies have highlighted large interindividual variability of muscle sympathetic nerve activity (MSNA) responsiveness to mental stress in humans. The purpose of this study was to examine blood pressure (BP) and MSNA responsiveness to mental stress in a large and generalizable cohort of young adults with and without family history of hypertension (FHH). We hypothesized that subjects with FHH would demonstrate greater sympathoexcitation to mental stress than subjects without FHH. A total of 87 subjects (55 men and 32 women, 18-40 yr of age) from recently published (n = 45) and ongoing (n = 42) studies were examined; 57 subjects (19 with FHH and 38 without FHH) had complete MSNA recordings at baseline. Heart rate (HR), BP, and MSNA were recorded during 5 min of supine rest and 5 min of mental stress (mental arithmetic). Resting MSNA and HR were not statistically different between subjects with and without FHH (P > 0.05), whereas resting mean arterial pressure was higher in subjects with FHH (86 ± 2 vs. 80 ± 1 mmHg, P < 0.05). Mental stress increased MSNA in subjects with FHH (Δ5 ± 1 bursts/min), but not in subjects without FHH [Δ1 ± 1 burst/min, P < 0.01 (time × group)]. Mental stress increased mean arterial pressure (Δ12 ± 1 and Δ10 ± 1 mmHg, P < 0.001) and HR (Δ19 ± 2 and Δ16 ± 2 beats/min, P < 0.001) in subjects with and without FHH, but these increases were not different between groups [P ≥ 0.05 (time × group)]. MSNA and BP reactivity to mental stress were not correlated in either group. In conclusion, FHH was associated with heightened MSNA reactivity to mental stress, despite a dissociation between MSNA and BP responsiveness.

Ambulatory blood pressure monitoring in healthy children with parental hypertension

The aim of this study was to compare ambulatory blood pressure monitoring (ABPM) parameters in offspring with at least one hypertensive parent (HP) to offspring with normotensive parents (NP) and to determine whether gender of parent or child might influence the association between parental hypertension and blood pressure (BP). Eighty-nine healthy children (mean age 11.1 +/- 3.9 years) with HP and 90 controls (mean age 10.5 +/- 3.1 years) with NP were recruited. Age, gender, and height did not differ between the two groups, whereas children of HP had higher weight, body mass index (BMI), and waist circumference compared with healthy controls. No difference was found in casual BP between the two groups. In contrast, during ABPM daytime and nighttime mean systolic and diastolic BP and mean arterial pressure (MAP) standard deviation scores (SDS) were significantly elevated in children with HP. The mean percentage of nocturnal BP decline (dipping) was not significantly different between the two groups. Children with hypertensive mothers had higher daytime systolic and MAP SDS than controls; no such difference was detected for children with hypertensive fathers. Daytime systolic and MAP SDS were significantly elevated in boys with HP compared with boys with NP but failed to be significant in girls. Multiple linear regression analysis showed that parental history of hypertension (B = 0.29) and BMI (B = 0.03) were independently correlated with increase of daytime MAP SDS. Early changes in ambulatory BP parameters were present in healthy children of HP. BP in HP offspring was influenced by the gender of the affected parent and the offspring.

Blood pressure and heart rate of students undergoing a medical licensing examination

AIMS

To assess the effect of a real life mental stress situation on blood pressure (BP) and heart rate (HR) in students undergoing a medical licensing examination.

METHOD

Prospective observational study of 121 medical students taking the final licensing exam. BP and HR were taken before and after the exam. Additionally, BP was measured by ambulatory BP monitoring device and HR was recorded continuously by an HR monitor belt in 25 students throughout the examination.

MAJOR FINDINGS

Diastolic BP (DBP) increased from 81 +/- 10 mmHg before the exam to 86 +/- 9 mmHg (p = 0.008) during the exam and to 88 +/- 11 mmHg, (p = 0.007) 15 min after the exam. Systolic BP (SBP) did not increase significantly during (from 131 +/- 14 before the exam to 136 +/- 18 mmHg) and after the exam (135 +/- 16 mmHg). HR decreased during (to 100 +/- 18 beats/min, p < 0.001), and after the exam (to 95 +/- 19 beats/min, p < 0.001) compared to values before the exam (114 +/- 19 beats/min). SBP was higher in male students compared to female students before (138 +/- 10 vs 125 +/- 18 mmHg) and after (126 +/- 18 vs 115 +/- 17 mmHg) the exam (p < 0.01).

CONCLUSION

Only DBP increased during medical licensing examination, albeit within a small range. SBP did not change significantly and HR decreased during the exam. Male students showed a higher SBP compared to female students.

Parental history of hypertension and hostility moderate cardiovascular responses to interpersonal conflict

A parental history of hypertension has been implicated in the development of hypertension, perhaps by virtue of an elevated cardiovascular response to stress. Similarly, hostility has been hypothesized to be linked to cardiovascular disease through cardiovascular hyperreactivity. The interaction of parental history and hostility in moderating cardiovascular response has been infrequently examined, though research suggests the two may be linked through familial factors. The present study examined the cardiovascular response of 98 healthy young adult males categorized as offspring of hypertensive subjects (PH+) or offspring of normotensive subjects (PH-) and as high or low hostile, based on Cook-Medley Hostility scores (HiHo vs. LoHo). Subjects were exposed to either an harassment or non-harassment stressor. Results indicated elevated cardiac output and forearm blood flow responses in PH+/HiHo subjects who were harassed as compared to any other harassed subject and all non-harassed individuals. This hemodynamic response pattern of elevated blood flow suggests a mechanism of hypertensive disease development.

Cardiovascular recovery from stress and hypertension risk factors: a meta-analytic review

Recent research has suggested that cardiovascular recovery from stress can play a potential role in hypertension pathogenesis. Sixty-nine studies were included in a meta-analytic review to evaluate the effect of various hypertension risk factors (e.g., race, lack of exercise) on cardiovascular recovery from stress. Small mean effect sizes were observed for studies examining hypertension status and race as risk factors associated with delayed diastolic blood pressure recovery. Lack of fitness was also associated with delayed heart rate recovery. These results revealed that, for the specified risk factors and cardiovascular variables, high-risk individuals exhibited delayed cardiovascular recovery as compared with low-risk individuals. Further, the relationships between hypertension status, race, and cardiovascular recovery were typically associated with the use of "active" laboratory stressors. The relationship between lack of fitness and cardiovascular recovery was also associated with the use of "active" and exercise laboratory stressors.

The effects of age, gender, and family history on blood pressure of normotensive college students

Offspring with a parental history of hypertension are, by some estimates, four times more likely to develop the disease (Corvol et al., 1992). While some studies suggest that an increased risk is observable in eight year old children, others suggest that the increased risk does not become apparent until age 20. This study examined this discrepancy by screening resting blood pressures from 403 young adults. After adjusting for body mass, a significant family history x age x gender interaction (p < .01) suggests that the effect of family history on systolic blood pressure varies by age and gender. The influence of positive family history becomes apparent in males by age 20 and in females by age 22. This relationship may help provide a rationale for interpretation and reconciliation of disparate results in the literature, and clarify our understanding of the etiologic mechanisms responsible for development of essential hypertension.

How many sphygmomanometric cuff inflations are necessary to obtain a hemodynamic baseline?

The purpose of this study was to determine the minimum number of consecutive blood pressure cuff inflations required to obtain seated stable resting baseline measurements of heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP). Sixty male college students aged 18 to 31 years volunteered as study subjects. Thirteen observations of HR, SBP, DBP, and MAP were recorded at 90-second intervals for each subject using a Critikon-Dinamap monitor. Stable readings for SBP and MAP were obtained in 6.5 minutes or 3 to 5 cuff inflations in the population tested. Using this procedure, additional age- and gender-specific norms could be established for normal and hypertensive subjects. Knowing the approximate quantity and frequency of blood pressure cuff inflations needed to generate baseline minimum measurements of HR, SBP, DBP, and MAP will be helpful in studies of cardiovascular reactivity, as well as for clinical and psychophysiologic treatment of hypertension.

Parental history of hypertension and cardiovascular response to stress in black and white men

White offspring of hypertensives typically exhibit an elevated cardiovascular response to stress. Studies of Black offspring of hypertensives have been fewer, with inconsistent results. This may be due, in part. to incomplete characterizations of hemodynamic responses. This study examines cardiovascular reactivity in Black and White offspring of hypertensives with a particular focus on vascular resistance responses. A total of 62 healthy normotensive men, 41 with a parental history of hypertension (PH+: 21 Blacks, 20 Whites), and 21 without parental hypertension (PH-: 7 Blacks, 14 Whites) engaged in a series of laboratory tasks. Both Black and White PH+ participants exhibited elevated diastolic blood pressure (DBP) responses, but to different patterns of stressor tasks. Familial differences in total peripheral resistance response were also obtained for Black and White participants in a comparison across all tasks, but were particularly evident in tasks when PH+ participants had elevated DBP responses. These results suggest that a parental history of hypertension is an important moderator of cardiovascular, and in particular peripheral vascular, responses to stress in Black and White individuals.

Cardiovascular reactions to blood donation in offspring of hypertensives and normotensives

Blood pressure and heart rate reactions of 182 confirmed offspring of normotensive (110 female, 72 male) and 112 offspring of hypertensive (66 female, 46 male) individuals to the stressor of blood donation were examined. Subjects were tested at two sites, one in the United States and one in Canada. Although influenced by site, young normotensive offspring of hypertensives generally exhibited significantly greater blood pressure levels in anticipation of donating blood than offspring of normotensives. The higher reactivity of offspring of hypertensives observed in stressful laboratory settings may generalize to more ecologically valid settings, even those which, like blood donation, require passive coping efforts.

Parasympathetic nervous system control of heart rate responses to stress in offspring of hypertensives

The elevated heart rate response to stress in normotensive offspring of hypertensives (PH+) has been suggested to be a function of sympathetic nervous system activity. This study examined whether parasympathetic nervous system activity may also underlie familial differences in the heart rate response. Twenty-four subjects, half of whom were PH+, were exposed to four stressor tasks administered in counterbalanced order. Stressors were chosen based on previous research that suggested vagal contributions to the heart rate response. Stressors were a cold pack to the forehead, isometric hand grip, a noxious film, and a shock-avoidance video game task. Physiological measures included heart rate (HR), respiration rate (RR), and respiratory sinus arrhythmia (RSA). RSA values were corrected for corresponding RR by analysis of covariance. Familial differences in HR were observed in response to the hand grip and video game tasks. However, in both cases analyses suggest that familial differences in reactivity were a function of primarily sympathetic as opposed to parasympathetic influences. Familial differences in RSA were not observed for rest or tasks. This study found no evidence for parasympathetic mediation of familial differences in the heart rate response to the stressors employed.