Kathleen C. Light

Effects of partner support on resting oxytocin, cortisol, norepinephrine, and blood pressure before and after warm partner contact

Objective: We examined whether the magnitude of plasma oxytocin (OT), norepinephrine (NE), cortisol, and blood pressure (BP) responses before and after a brief episode of warm contact (WC) with the spouse/partner may be related to the strength of perceived partner support. Methods: Subjects were 38 cohabiting couples (38 men, 38 women) aged 20 to 49 years. All underwent 10 minutes of resting baseline alone, 10 minutes of WC together with their partner, and 10 minutes of postcontact rest alone. Results: Greater partner support (based on self-report) was related to higher plasma oxytocin in men and women across the protocol before and after WC. In women, higher partner support was correlated with lower systolic blood pressure (SBP) during solitary rest after WC but not before. Also, higher OT in women was linked to lower BP at baseline and to lower NE at all 4 measurements. Conclusion: Greater partner support is linked to higher OT for both men and women; however, the importance of OT and its potentially cardioprotective effects on sympathetic activity and BP may be greater for women. ABP = ambulatory blood pressure; BMI = body mass index; BP = blood pressure; CVD = cardiovascular disease; DBP = diastolic blood pressure; HPA = hypothalamic–pituitary–adrenal; HR = heart rate; IV = intravenous; MI = myocardial infarction; NE = norepinephrine; OT = oxytocin; SBP = systolic blood pressure; SNS = sympathetic nervous system; SRI = Social Relationships Index; WC = warm contact.

More frequent partner hugs and higher oxytocin levels are linked to lower blood pressure and heart rate in premenopausal women

In animals, ventral stroking for >5 days increases oxytocin (OT) activity and decreases blood pressure (BP), but related human studies are few. Thus, relationships between self-reported frequency of partner hugs, plasma OT and BP levels were examined in 59 premenopausal women before and after warm contact with their husbands/partners ending with hugs. Higher baseline OT before partner contact was associated with lower BP and heart rate, and met criteria to be a partial mediator of the lower resting BP shown by women reporting more frequent hugs (P<0.05). OT levels during post-contact stress were unrelated to hugs or BP. Menstrual cycle phase did not influence any OT measure. Thus, frequent hugs between spouses/partners are associated with lower BP and higher OT levels in premenopausal women; OT-mediated reduction in central adrenergic activity and peripheral effects of OT on the heart and vasculature are pathways to examine in future research.

Ischemic, Hemodynamic, and Neurohormonal Responses to Mental and Exercise Stress Experience From the Psychophysiological Investigations of Myocardial Ischemia Study (PIMI)

BACKGROUND The pathophysiology of mental stress-induced myocardial ischemia, which occurs at lower heart rates than during physical stress, is not well understood. METHODS AND RESULTS The Psychophysiological Investigations of Myocardial Ischemia Study (PIMI) evaluated the physiological and neuroendocrine functioning in unmedicated patients with stable coronary artery disease and exercise-induced ischemia. Hemodynamic and neurohormonal responses to bicycle exercise, public speaking, and the Stroop test were measured by radionuclide ventriculography, ECG, and blood pressure and catecholamine monitoring. With mental stress, there were increases in heart rate, systolic blood pressure, cardiac output, and systemic vascular resistance that were correlated with increases in plasma epinephrine. During exercise, systemic vascular resistance fell, and there was no relationship between the hemodynamic changes and epinephrine levels. The fall in ejection fraction was greater with mental stress than exercise. During mental stress, the changes in ejection fraction were inversely correlated with the changes in systemic vascular resistance. Evidence for myocardial ischemia was present in 92% of patients during bicycle exercise and in 58% of patients during mental stress. Greater increases in plasma epinephrine and norepinephrine occurred with ischemia during exercise, and greater increases in systemic vascular resistance occurred with ischemia during mental stress. CONCLUSIONS Mental stress-induced myocardial ischemia is associated with a significant increase in systemic vascular resistance and a relatively minor increase in heart rate and rate-pressure product compared with ischemia induced by exercise. These hemodynamic responses to mental stress can be mediated by the adrenal secretion of epinephrine. The pathophysiological mechanism involved are important in the understanding of the etiology of myocardial ischemia and perhaps in the selection of appropriate anti-ischemic therapy.

Influence of a "Warm Touch" Support Enhancement Intervention Among Married Couples on Ambulatory Blood Pressure, Oxytocin, Alpha Amylase, and Cortisol

Objective: To investigate whether a support intervention (warm touch enhancement) influences physiological stress systems that are linked to important health outcomes. Growing evidence points to a protective effect of social and emotional support on both morbidity and mortality. Methods: In this study, 34 healthy married couples (n = 68), aged 20 to 39 years (mean = 25.2 years), were randomly assigned to a “behavior monitoring” control group or participated in a 4-week intervention study in which clinic levels of plasma oxytocin, 24-hour ambulatory blood pressure, and salivary cortisol and alpha amylase were obtained pre and post intervention, at the same time salivary oxytocin was taken at home during weeks 1 and 4. Results: Salivary oxytocin was enhanced both early and late in the intervention group and alpha amylase was reduced at post treatment in intervention group husbands and wives relative to controls. Husbands in the intervention group had significantly lower post treatment 24-hour systolic blood pressure than the control group. Conclusion: Increasing warm touch among couples has a beneficial influence on multiple stress-sensitive systems. BP = blood pressure; ABP = ambulatory blood pressure; SBP = systolic blood pressure; DBP = diastolic blood pressure; OT = oxytocin; HPA = hypothalamic-pituitary adrenocortical; SNS = sympathetic nervous system; AUC = area under the curve.

Heart rate variability in patients with coronary artery disease: Differences in patients with higher and lower depression scores.

Objective This study tested the hypothesis that coronary artery disease patients with higher depression scores have lower heart rate variability during daily life. Method: Thirty-three men and nine women, ranging in age from 46 to 79, with coronary artery disease and exercise-induced ischemia were studied. The standard deviation of normal R-R intervals (SDNN) and average heart rate were obtained from 24-hour ambulatory electrocardiographic monitoring. Patients were grouped by a median split of the Minnesota Multiphasic Personality Inventory (MMPI-D) score. Results: SDNN was lower (p =.009) and average heart rate was higher (p =.003) in patients with higher depression scores. These relationships remained substantially unaltered after statistically adjusting for the only demographic/clinical factor that varied between the groups: gender. Conclusions: In comparison to the lower depression score group, those with higher depression scores had lower heart rate variability during daily life. These findings may be related to the reported relationship between depression and survival risk in patients with coronary artery disease.

Allopregnanolone levels and reactivity to mental stress in premenstrual dysphoric disorder.

BACKGROUND This study was designed to examine basal and stress-induced levels of the neuroactive progesterone metabolite, allopregnanolone, in women with premenstrual dysphoric disorder (PMDD) and healthy control subjects. Also, because evidence suggests that allopregnanolone negatively modulates the hypothalamic-pituitary-adrenal axis, plasma cortisol levels were examined. An additional goal was to investigate the relationship between premenstrual symptom severity and luteal phase allopregnanolone levels. METHODS Twenty-four women meeting prospective criteria for PMDD were compared with 12 controls during both the follicular and luteal phases of confirmed ovulatory cycles, counterbalancing phase at first testing. Plasma allopregnanolone and cortisol were sampled after an extended baseline period and again 17 min following the onset of mental stress. Owing to low follicular phase allopregnanolone levels, only luteal phase allopregnanolone and cortisol were analyzed. RESULTS During the luteal phase, PMDD women had significantly greater allopregnanolone levels, coupled with significantly lower cortisol levels, during both baseline and mental stress. Moreover, significantly more controls (83%) showed the expected stress-induced increases in allopregnanolone compared with PMDD women (42%). Premenstrual dysphoric disorder women also exhibited a significantly greater allopregnanolone/progesterone ratio than control subjects, suggesting alterations in the metabolic pathways involved in the conversion of progesterone to allopregnanolone. Finally, PMDD women with greater levels of premenstrual anxiety and irritability had significantly reduced allopregnanolone levels in the luteal phase relative to less symptomatic PMDD women. No relationship between symptom severity and allopregnanolone was observed in controls. CONCLUSIONS These results suggest dysregulation of allopregnanolone mechanisms in PMDD and that continued investigations into a potential pathophysiologic role of allopregnanolone in PMDD are warranted.

Orthostatic hypotension predicts mortality in middle-aged adults: the Atherosclerosis Risk In Communities (ARIC) Study.

Background— An association between orthostatic hypotension (OH) and mortality has been reported, but studies are limited to older adults or high-risk populations. Methods and Results— We investigated the association between OH (a decrease of 20 mm Hg in systolic blood pressure or a decrease of 10 mm Hg in diastolic blood pressure on standing) and 13-year mortality among middle-aged black and white men and women from the Atherosclerosis Risk in Communities Study (1987–1989). At baseline, 674 participants (5%) had OH. All-cause mortality was higher among those with (13.7%) than without (4.2%) OH. After we controlled for ethnicity, gender, and age, the hazard ratio (HR) for OH for all-cause mortality was 2.4 (95% confidence interval [CI], 2.1 to 2.8). Adjustment for risk factors for cardiovascular disease and mortality and selected health conditions at baseline attenuated but did not completely explain this association (HR=1.7; 95% CI, 1.4 to 2.0). This association persisted among subsets that (1) excluded those who died within the first 2 years of follow-up and (2) were limited to those without coronary heart disease, cancer, stroke, diabetes, hypertension, or fair/poor perceived health status at baseline. In analyses by causes of death, a significant increased hazard of death among those with versus without OH persisted after adjustment for risk factors for cardiovascular disease (HR=2.0; 95% CI, 1.6 to 2.7) and other deaths (HR=2.1; 95% CI, 1.6 to 2.8) but not for cancer (odds ratio=1.1; 95% CI, 0.8 to 1.6). Conclusions— OH predicts mortality in middle-aged adults. This association is only partly explained by traditional risk factors for cardiovascular disease and overall mortality.

Gender differences in blood pressure control during a variety of behavioral stressors.

&NA; This study assessed gender differences in hemodynamic response patterns to behavioral stressors. In addition, the extent to which gender differences in cardiovascular reactivity were a function of the type of challenge was determined by employing tasks relying on stereotypically male areas of competence and a task relying on stereotypically female areas of competence. Sixteen female and 15 male graduate, medical or dental students were exposed to two speech tasks and two math tasks. While there were no significant differences in blood pressure reactivity between the genders, females exhibited significantly greater cardiac output increases across all tasks than males, while males tended to respond with greater increases in total peripheral resistance compared with females. Furthermore, during two of the tasks, significantly more females were classified as myocardial hyperreactors (based on increases in cardiac output), while significantly more males were vascular hyperreactors (based on increases in total peripheral resistance). A post hoc analysis also indicated an apparent association between oral contraceptive use and higher cardiovascular reactivity among the females tested. This association may have been a consequence of the decision to test all women during days 10 to 14 of the menstrual cycle when reactivity in women not using oral contraceptives may be suppressed.

Mental Stress-Induced Ischemia and All-Cause Mortality in Patients With Coronary Artery Disease Results From the Psychophysiological Investigations of Myocardial Ischemia Study

Background—Ischemia during laboratory mental stress tests has been linked to significantly higher rates of adverse cardiac events. Previous studies have not been designed to detect differences in mortality rates. Methods and Results—To determine whether mental stress–induced ischemia predicts death, we evaluated 196 patients from the Psychophysiological Investigations of Myocardial Ischemia (PIMI) study who had documented coronary artery disease and exercise-induced ischemia. Participants underwent bicycle exercise and psychological stress testing with radionuclide imaging. Cardiac function data and psychological test results were collected. Vital status was ascertained by telephone and by querying Social Security records 3.5±0.4 years and 5.2±0.4 years later. Of the 17 participants who had died, new or worsened wall motion abnormalities during the speech test were present in 40% compared with 19% of survivors (P =0.04) and significantly predicted death (rate ratio=3.0; 95% CI, 1.04 to 8.36;P =0.04). Ejection fraction changes during the speech test were similar in patients who died and in survivors (P =0.9) and did not predict death even after adjusting for resting ejection fraction (P =0.63), which was similar in both groups (mean, 56.4 versus 59.7;P =0.24). Other indicators of ischemia during the speech test (ST-segment depression, chest pain) did not predict death, nor did psychological traits, hemodynamic responses to the speech test, or markers of the presence and severity of ischemia during daily life and exercise. Conclusions—In patients with coronary artery disease and exercise-induced ischemia, the presence of mental stress–induced ischemia predicts subsequent death.

High stress responsivity predicts later blood pressure only in combination with positive family history and high life stress.

High cardiovascular responsivity to stressors has not consistently improved prediction of later blood pressure increases beyond the predictive effects of baseline pressure. Animal models suggest that genetic susceptibility to hypertension and frequent stress exposure are important modulating factors in stress-related hypertension. Thus in 103 men originally tested at age 18 to 22 years and reassessed 10 years later, interactive effects of genetic susceptibility (defined as 1 or more hypertensive parents) with high stress responsivity (defined as top 25% on the basis of blood pressure and cardiac responses during both reaction time and cold pressor tasks) were examined in relation to follow-up systolic and diastolic levels and to change in blood pressure status from normal (diastolic<80 mm Hg) to marginally elevated (diastolic 85 to 95 mm Hg). Men with the combination of high stress response and hypertensive parents demonstrated higher systolic (P<0.05) and diastolic levels (P<0.05) at follow-up, and they showed a 7-fold increase (7.5, 95% confidence intervals 2.3, 24.3; P<0.001) in relative risk of change in blood pressure status versus men with no family history and a 3-fold increase (3.8, confidence intervals 1.5, 9.6; P<0.004) versus less stress-responsive men who also had hypertensive parents. In 65 men who also provided ratings of daily stress, family historyxstress responsivityxdaily stress interactions were significant in predicting follow-up systolic and diastolic levels (P<0.006 and 0.03, respectively), with highest pressure levels seen when high life stress was reported by high stress responders and/or men with hypertensive parents. In conclusion, results suggest that stress responsivity as a long-term predictor is modulated by both genetic and environmental factors.