Physiological stress responses in defensive individuals: Age and sex matter

The association between defensiveness and physiological responses to stress were evaluated in 81 healthy working men and 118 women, aged 20 to 64 years (M=41; SD=11.45). Participants underwent laboratory testing during which they were exposed to interpersonal stressors. Heart rate (HR), heart rate variability (HRV), blood pressure (BP), and salivary cortisol were measured. Defensiveness was evaluated using the Marlowe‐Crowne Social Desirability Scale. In women, higher defensiveness was associated with greater BP and HR reactivity to stress (p<.05). In older men, lower defensiveness was associated with increased systolic BP reactivity to stress (p<.02), delayed HRV recovery (p<.02), and greater salivary cortisol levels (p<.02). In conclusion, greater defensiveness was associated with increased reactivity to stress in women whereas in older men, lower defensiveness was associated with elevated cardiovascular, autonomic, and endocrine responses to stress.     

Establishing the validity of a novel passive stress task

Laboratory tasks used to elicit a cardiovascular stress response in the laboratory can involve either active or passive coping. However, in previous work, passive stress tasks often incorporate a distinct physical stress element, such as the handgrip or cold pressor task, meaning observed changes in cardiovascular parameters may be the result of the physical element of the stressor rather than truly reflecting psychological stress. The present study aimed to establish the validity of a psychological passive stressor; one more analogous to active tasks than those previously employed in laboratory studies. Twenty-six young, healthy adults completed a speech task in the laboratory following a resting baseline period. Twelve months later, they were invited back to the laboratory and watched the video recording of their speech. Analyses confirmed that while both tasks elicited significant SBP and DBP change (all ps < .001), only the active task was associated with HR and CO reactivity (both ps < .001), while only the passive task was associated with TPR reactivity (p = .028). Furthermore, the passive stressor was associated with a mixed hemodynamic profile, whereas the active stressor was associated with a clear myocardial profile. This study confirms that watching a video recording of oneself complete a speech task is associated with a more vascular response profile, a response associated with passive coping contexts.     

Potential benefits of mindfulness during pregnancy on maternal autonomic nervous system function and infant development

Mindfulness is known to decrease psychological distress. Possible benefits in pregnancy have rarely been explored. Our aim was to examine the prospective association of mindfulness with autonomic nervous system function during pregnancy and with later infant social‐emotional development. Pregnant women (N = 156) completed self‐report mindfulness and emotional distress questionnaires, and had their autonomic function assessed in their first and third trimesters, including heart rate (HR), indices of heart rate variability (HRV), preejection period (PEP), and systolic (SBP) and diastolic blood pressure (DBP). The social‐emotional development of 109 infants was assessed at 4 months of age. More mindful pregnant women had less prenatal and postnatal emotional distress (p < .001) and higher cardiac parasympathetic activity: root mean square of successive differences (RMSSD: p = .03) and high‐frequency (HF) HRV (p = .02). Between the first and third trimesters, women's overall HR increased (p < .001), and HRV (RMSSD, HF HRV, and low‐frequency (LF) HRV: p < .001) and PEP decreased (p < .001). In more mindful mothers, parasympathetic activity decreased less (RMSSD: p = .01; HF HRV: p = .03) and sympathetic activity (inversely related to PEP) increased less (PEP: p = .02) between trimesters. Their offspring displayed less negative social‐emotional behavior (p = .03) compared to offspring of less mindful mothers. Mindfulness in pregnancy was associated with ANS changes likely to be adaptive and with better social‐emotional offspring development. Interventions to increase mindfulness during pregnancy might improve maternal and offspring health, but randomized trials are needed to demonstrate this.     

Pure purr virtual reality technology: measuring heart rate variability and anxiety levels in healthy volunteers affected by moderate stress

IntroductionTraditional approaches to stress management are difficult to learn and to implicate in daily life. Emerging technologies like virtual reality (VR) have become a target of extensive study for recreational and medical purposes. The autonomic nervous system (ANS) plays a crucial role in stress response, post-stress relaxation, and recovery. This study aimed to assess the effect of modified VR intervention on short-term heart rate variability (HRV) and perceived anxiety levels in healthy volunteers affected by moderate stress. The stressors included mental arithmetic tasks.Material and methodsThe study involved healthy adults, of both sexes, aged 20 to 60 years, without history of cardiovascular diseases, essential abnormalities on ECG, and with normal or moderate level of situational anxiety. The VR gadgets used in the study were commercially available Bobo-VR X1 headsets, one with modification for medical applications (Pure Purr technology) and one with none (sham technology). The investigational (Pure Purr) headset with an audio-visual sequence was modified by adding a binaural effect and was synchronised with the tract of respiratory movements and the frequency of heart rate. To track changes in the ANS, participants underwent both electrocardiography (ECG) and measurement of HRV.ResultsThe findings showed a significant increase in parasympathetic activity after 5-minute exposure to the investigational device compared to stress, as shown by high-frequency HRV (499.8 ms² and 340.5 ms², p < 0.001). RMSSD for a modified headset was higher (p = 0.02) compared to a sham headset with no modifications (RMSSD difference of 12.3% (2.6% to 23.1%)). The LF/HF ratio, however, was lower (difference of 14.5% (2.6% to 23.1%), p = 0.04).ConclusionsThese findings suggest that a medical device with pre-installed Pure Purr software had a significant effect on the recovery of the ANS in healthy volunteers affected by moderate stress.     

Associations between digit ratio (2D4D), mood,and autonomic stress response in healthy men

The ratio between the length of the second (index) and the fourth (ring) finger (2D4D) is a putative biomarker of prenatal testosterone (T) exposure, with higher exposure leading to a smaller ratio. 2D4D has further been linked to mental and somatic disorders. Healthy male Swiss recruits (N = 245; M_age = 20.30 years) underwent a psychosocial stress test. Mood and salivary alpha‐amylase (sAA) were assessed before and after the stress test, while heart rate (HR) and heart rate variability (HRV) were measured continuously. Additionally, 2D4D (right: R2D4D; left: L2D4D) was determined and divided into quartile groups. Correlation analysis showed no associations between R/L2D4D and outcome measures. Comparing calculated quartiles for R2D4D, subjects in the lowest R2D4D quartile expressed trendwise (p < 0.10) lower positive and higher negative affect, significantly elevated sAA activity (p < 0.05), but no HR and HRV differences at baseline as compared to subjects in the upper three quartiles. With regard to acute stress, subjects in the lowest as compared to subjects in the upper three R2D4D quartiles showed a higher increase of negative affect and a stronger cardiac response (p < 0.05), but no alterations in positive affect and sAA activity. Young healthy men in the lowest R2D4D quartile revealed a more negative affect and increased physiological activity at baseline and in response to acute stress. An exposure to high levels of prenatal T might constitute a risk factor potentially increasing vulnerability to stress‐related disorders in men.     

Inducible nitric oxide synthase inhibition attenuates lung tissue responsiveness and remodeling in a model of chronic pulmonary inflammation in guinea pigs

We evaluated the influence of iNOS-derived NO on the mechanics, inflammatory, and remodeling process in peripheral lung parenchyma of guinea pigs with chronic pulmonary allergic inflammation. Animals treated or not with 1400 W were submitted to seven exposures of ovalbumin in increasing doses. Seventy-two hours after the 7th inhalation, lung strips were suspended in a Krebs organ bath, and tissue resistance and elastance measured at baseline and after ovalbumin challenge. The strips were submitted to histopathological measurements. The ovalbumin-exposed animals showed increased maximal responses of resistance and elastance (p < 0.05), eosinophils counting (p < 0.001), iNOS-positive cells (p < 0.001), collagen and elastic fiber deposition (p < 0.05), actin density (p < 0.05) and 8-iso-PGF2α expression (p < 0.001) in alveolar septa compared to saline-exposed ones. Ovalbumin-exposed animals treated with 1400 W had a significant reduction in lung functional and histopathological findings (p < 0.05). We showed that iNOS-specific inhibition attenuates lung parenchyma constriction, inflammation, and remodeling, suggesting NO-participation in the modulation of the oxidative stress pathway.     

Sex differences in adolescents’ cardiac reactivity and recovery under acute stress: The importance of nonlinear measures

How well adolescents can self-regulate in the face of stressors has considerable implications for long-term well-being and risk of psychopathology. This study investigated sex differences in adolescents’ cardiac reactivity and recovery during a stressful task. Measures of cardiac variability (linear) and complexity (nonlinear) were obtained from N = 92 adolescents, 41 males (M age = 13.28, SD = 0.69; BMI = 21.9) and 51 females (M age = 13.36, SD = 0.67; BMI = 21.5). The adolescents underwent the Trier Social Stress Test, consisting of five conditions: baseline, anticipation, social exposure, math task, and recovery. Repeated measures ANOVAs revealed that female in comparison to male adolescents showed lower cardiac complexity revealed by higher short-term scaling exponent at baseline (p = .006) and math (p = .013) and lower entropy at exposure (p = .013) and math (p = .012). A marginal between-groups effect was found for Higuchi's fractal dimension, F(1, 90) = 3.67, p = .059, η_p² = .041, with females showing lower fractal dimension than males in math (p = .037). Linear measures did not reveal sex-related differences. Results suggest that adolescent females show lower cardiac complexity during stress. These findings support the importance of nonlinear cardiac measures for understanding cardiac reactivity during stress. Further research is needed to test the hypothesis that cardiac complexity is useful to detect an increased risk of emotional disorders, disorders that are more prevalent in women.     

The effects of social interactions on momentary stress and mood during COVID-19 lockdowns

Objective

Social interactions are vital for our well-being, particularly during times of stress. However, previous studies linking social interactions to psychological outcomes during the COVID-19 pandemic have largely been retrospective and/or cross-sectional. Thus, we tested four preregistered hypotheses (H1–H4) concerning the real-time effect of social interactions on momentary changes in stress and mood during two COVID-19 lockdowns.

Design

We used an ecological momentary assessment approach in 732 participants in spring 2020 (burst 1) and in a subsample of these participants (n = 281) during a further lockdown in autumn/winter 2020 (burst 2).

Methods

Participants reported their stress and mood in a smartphone app five times per day for 7 days and indicated the nature and frequency of their recent social interactions.

Results

Social interactions (H1) and their frequency (H2) improved momentary affect (e.g., social interactions increased mood valence: estimate = 2.605, p < .001 for burst 1). This was particularly the case for face-to-face interactions which, compared with other types of interactions, reduced momentary stress (e.g., estimate = −2.285, p < .001 for burst 1) and boosted mood (e.g., estimate = 1.759, p < .001 for burst 1) across both lockdowns, even when controlling for the pleasantness of the interaction and the closeness of the interaction partner (H3). We also show that individual differences in people's responsiveness to different social rewards modulated the impact of social interactions on momentary mood (H4).

Conclusions

This study extends findings from cross-sectional and retrospective studies by highlighting the real-time affective benefits of social interactions during COVID-19 lockdown. The results have important implications for the (self-) management of stress and mood during psychologically demanding periods.     

Cardiac measures of nuclear power plant operator stress during simulated incident and accident scenarios

Maintaining optimal performance in demanding situations is challenged by stress‐induced alterations in performance. Here, we quantified the stress of nuclear power plant (NPP) operators (N = 20) during a full‐scale simulator training for incident and accident scenarios. We compared the ambulatory electrocardiography measurements of heart rate (HR) and heart rate variability (HRV), and self‐reported stress during baselines and simulated scenarios. Perceived (scale 0–10) and physiologically measured stress were low during baseline after the scenarios and normal NPP operation (means 1.8–2.2, mean HR 75–80 bpm). During a cognitively challenging scenario simulating a sensor malfunction, the operators' stress was mild to moderate (mean 3.4; HR + 12% from baseline). During simulations of severe accidents of fire and radioactive steam leakage, the experienced stress and cardiac activity were on a moderate to high level (means 4.2 and 4.6; HR + 23% and + 14% from baseline, respectively). Cardiac activity paralleled the self‐reported stress: correlation of self‐reported stress to HR was 0.61 (p < .001) and to HRV features RMSSD, HF, LF/HF, SD1, and SD1/SD2 were ?0.26, ?0.28, 0.35, ?0.40, and ?0.39 (p < .01), respectively. The low shared variance (22%) between HR and physical activity further support the interpretation that the cardiac activity was strongly linked to the experience of stress and not accountable by operators' movement within the simulator. Cardiac measurements in naturalistic settings can thus reveal relevant information on acute stress with the benefit of not interrupting the primary task.     

Inclusion of a rest period in diaphragmatic breathing increases high frequency heart rate variability: Implications for behavioral therapy

Heart rate variability (HRV) is associated with positive physiological and psychological effects. HRV is affected by breathing parameters, yet debate remains regarding the best breathing interventions for strengthening HRV. The objective of the current study was to test whether the inclusion of a postexhalation rest period was effective at increasing HRV, while controlling for breathing rate. A within‐subject crossover design was used with 40 participants who were assigned randomly to a breathing pattern including a postexhalation rest period or a breathing pattern that omitted the postexhalation rest period. Participants completed training on each breathing pattern, practiced for 6 min, and sat quietly during a 5‐min washout period between practices. Participants were given instructions for diaphragmatic breathing at a pace of six breaths/minute with or without a postexhalation rest period. Recordings of heart rate, breathing rate, HF‐HRV, RMSSD, LF‐HRV, and SDNN were collected before and during each of the breathing trials. HRV indices were derived from Lead 1 ECG recordings. Pairwise contrasts showed that inclusion of a postexhalation rest period significantly decreased heart rate (p < .001) and increased HF‐HRV (p < .05). No differences were found for breathing rates (p > .05), RMSSD (p > .05), and SDNN (p > .05). Results indicated that omission of the postexhalation rest period resulted in higher LF‐HRV (p < .05). A postexhalation rest period improves HF‐HRV, commonly associated with self‐regulatory control, yet the importance of a postexhalation rest period requires further exploration.     

The incidence of stress symptoms and heart rate variability during sleep and orthostatic test

This study examined the relation of self-reported stress to cardiac autonomic modulation in real-life conditions. The participants for the study were healthy male (N = 59) and female (N = 40) employees (age 40 ± 10 years). A single-item question and a 14-item questionnaire on perceived stress were administered to the participants before the experimental night. RR-intervals (RRI) were recorded during night sleep and an orthostatic test after awakening at home. The RRI data were analyzed for heart rate (HR) and heart rate variability (HRV) in time and frequency domains. Nocturnal urinary stress hormone (cortisol, adrenal and noradrenal) secretion was also analyzed. Based on the self-reported stress, the participants were divided into either low or high stress group. The results showed that higher incidence of stress symptoms was significantly associated with lower HRV in the orthostatic test regardless of age and gender. Differences between the stress groups in HRV indices were approximately 20–50 and 30–75% in supine and standing positions, respectively. No difference was found in nocturnal HR, HRV, or stress hormone secretion between the stress groups. Higher incidence of stress symptoms was significantly associated with greater decrease of HRV from night sleep to the orthostatic test, as a response to awakening. In conclusion, the present findings support the view that autonomic modulation measured in the orthostatic test, but not during night sleep, is related to self-reported stress.     

Defensiveness and metabolic syndrome: Impact of sex and age

The association between defensiveness and metabolic burden, as well as the moderating effects of sex and age were evaluated in 199 healthy working men (N = 81) and women (N = 118), aged 20–64 years (M = 41; S.D. = 11.45). Defensiveness (Marlowe–Crowne Social Desirability Scale) and parameters of metabolic syndrome (MS; waist circumference, HDL, triglycerides, glucose, 24 h ambulatory blood pressure) were obtained. In men, defensiveness was inversely related to MS burden (Beta = −.288; p = .001), as well as to individual measures of SBP, DBP, glucose and waist circumference (p < .05). In older women, high defensiveness was associated with a greater MS burden (p = .050) and glucose level (p = .005) while the reverse was true in younger women (p = .012). In conclusion, defensiveness was associated with a worse metabolic profile in older women but may be protective for men and younger women. Understanding the pathophysiological processes underlying these associations could elucidate sex and age differences and inform prevention efforts.     

Effects of exercise intensity and duration on nocturnal heart rate variability and sleep quality

Acute physical exercise may affect cardiac autonomic modulation hours or even days during the recovery phase. Although sleep is an essential recovery period, the information on nocturnal autonomic modulation indicated by heart rate variability (HRV) after different exercises is mostly lacking. Therefore, this study investigated the effects of exercise intensity and duration on nocturnal HR, HRV, HR, and HRV-based relaxation, as well as on actigraphic and subjective sleep quality. Fourteen healthy male subjects (age 36 ± 4 years, maximal oxygen uptake 49 ± 4 ml/kg/min) performed five different running exercises on separate occasions starting at 6 p.m. with HR guidance at home. The effect of intensity was studied with 30 min of exercises at intensities corresponding to HR level at 45% (easy), 60% (moderate) and 75% (vigorous) of their maximal oxygen uptake. The effect of duration was studied with 30, 60, and 90 min of moderate exercises. Increased exercise intensity elevated nocturnal HR compared to control day (p < 0.001), but it did not affect nocturnal HRV. Nocturnal HR was greater after the day with 90- than 30- or 60-min exercises (p < 0.01) or control day (p < 0.001). Nocturnal HRV was lower after the 90-min exercise day compared to control day (p < 0.01). Neither exercise intensity nor duration had any impact on actigraphic or subjective sleep quality. The results suggest that increased exercise intensity and/or duration cause delayed recovery of nocturnal cardiac autonomic modulation, although long exercise duration was needed to induce changes in nocturnal HRV. Increased exercise intensity or duration does not seem to disrupt sleep quality.     

Heart rate variability in overactive bladder experimental model

Introduction

Two main pathophysiological concepts of overactive bladder (OAB) are postulated: the neurogenic and myogenic theories. Autonomic nervous system (ANS) dysfunction is also involved in OAB pathophysiology. The purpose of our study was to estimate ANS activity by heart rate variability (HRV) assessment in two OAB experimental models evoked by cyclophosphamide administration: acute (AOAB) and chronic (COAB) overactive ones.

Material and methods

In the AOAB model, an i.p. dose of cyclophosphamide was administered (200 mg/kg body weight) while the COAB model received 4 times the i.p. administration of cyclophosphamide (75 mg/kg body weight). In each subject, after urethane anaesthesia (1.2 g/kg body weight), 20-minute ECG recordings (PowerLab) were performed with subsequent HRV analysis.

Results

Most of the differences in time domain analysis parameters were insignificant, except those concerning SDNN and rMSSD (p < 0.05). In frequency analysis, a power decrease of all standard spectral components was revealed in both OAB groups. In AOAB, TP (1.43 ±1.21 vs. 7.92 ±6.22 in control; p < 0.05) and VLF (0.95 ±1.08 vs. 6.97 ±5.99 in control; p < 0.05) showed significant power decrease, whereas the COAB group was mostly characterized by LF (0.09 ±0.15 vs. 0.34 ±0.33 in control; p < 0.05) and HF (0.25 ±0.29 vs. 0.60 ±0.41 in control; p < 0.05) decrease.

Conclusions

The ANS disturbances, found as standard spectral parameter abnormalities, were demonstrated in both AOAB and COAB. When this finding is analysed, together with the lack of statistically significant differences in normalized nLF and nHF powers, the VLF changes seem to play an essential role, probably reflecting the progression in bladder inflammatory changes.     

Comparative effects of a prenatal stress occurring during early or late gestation on pig immune response

The aim of this work was to investigate the immune effects of prenatal stress (PNS) in pigs, when maternal stressor is applied during early or late gestation. In two separate experiments, gilts were submitted to a social-stress routine between either days 24 and 48 (stress (S) group, n = 8 vs. control (C) group, n = 6) or days 79 and 103 of gestation (S group, n = 10 vs. C group, n = 7). During the first month of life of the piglets, their cortisol levels were assessed in basal state and after stressful events (castration, new environment, and weaning). Piglets were immunized against ovalbumin (OVA) at 7 (D7) and 19 (D19) days of age. Lymphocyte proliferation in response to OVA and mitogens was investigated in blood in both sexes from D5 to D29 as well as in the spleen, thymus and crural lymph nodes from females euthanized on D5 and D26. On D27, the cytokine response of male piglets to an injection of lipopolysaccharide was investigated. Special care was taken to minimize the stress at blood sampling and euthanasia. We found that early gestational stress only affected the relative weight of adrenals on D5 (S < C, P < 0.05). On the contrary, late gestational stress increased the proliferation index of blood cells regardless of the age, in both sexes in response to PHA (P = 0.06), and in females only in response to ConA (P < 0.01) and PWM (P < 0.05). Overall, the effects of PNS in pigs seem to depend on the stage of gestation, gender and the immune compartment.     

Reduced heart rate variability predicts poor sleep quality in a case–control study of chronic fatigue syndrome

Parasympathetic function is important in the induction and maintenance of sleep. We examined whether nocturnal vagal modulation of heart rate is related to the poor sleep quality commonly reported in chronic fatigue syndrome (CFS). Heart rate (HR, as R–R intervals) was continuously monitored during sleep in 20 patients with CFS and 20 matched control subjects. Questionnaires assessed demographic information, symptoms, functional impairment, and subjective sleep quality. CFS was associated with more sleep problems in general and poorer subjective sleep quality on the study night (all p < 0.003), and reports of repeated awakening during the night were 7 times more likely compared to healthy subjects (p = 0.017). Time and frequency-domain parameters of HR variability during sleep were significantly lower in patients with CFS (all p < 0.006). Multiple regression analyses revealed that heart rate variability (HRV) parameters were the best predictors of subjective sleep measures. This study identified significant reductions in vagal modulation of heart rate during sleep in CFS. Low HRV strongly predicted sleep quality—suggesting a pervasive state of nocturnal sympathetic hypervigilance in CFS.     

Openness to experience and adapting to change: Cardiovascular stress habituation to change in acute stress exposure

Underlying psychophysiological mechanisms of effect linking openness to experience to health outcomes, and particularly cardiovascular well‐being, are unknown. This study examined the role of openness in the context of cardiovascular responsivity to acute psychological stress. Continuous cardiovascular response data were collected for 74 healthy young female adults across an experimental protocol, including differing counterbalanced acute stressors. Openness was measured via self‐report questionnaire. Analysis of covariance revealed openness was associated with systolic blood pressure (SBP; p = .016), and diastolic blood pressure (DBP; p = .036) responsivity across the protocol. Openness was also associated with heart rate (HR) responding to the initial stress exposure (p = .044). Examination of cardiovascular adaptation revealed that higher openness was associated with significant SBP (p = .001), DBP (p = .009), and HR (p = .002) habituation in response to the second differing acute stress exposure. Taken together, the findings suggest persons higher in openness are characterized by an adaptive cardiovascular stress response profile within the context of changing acute stress exposures. This study is also the first to demonstrate individual differences in cardiovascular adaptation across a protocol consisting of differing stress exposures. More broadly, this research also suggests that future research may benefit from conceptualizing an adaptive fitness of openness within the context of change. In summary, the present study provides evidence that higher openness stimulates short‐term stress responsivity, while ensuring cardiovascular habituation to change in stress across time.     

Perioperative Psychological and Music Interventions in Elderly Patients Undergoing Spinal Anesthesia: Effect on Anxiety,Heart Rate Variability,and Postoperative Pain

Purpose

The aim of this study was to evaluate the effects of perioperative psychological and music interventions in elderly patients undergoing elective surgery on anxiety, post-operative pain, and changes in heart rate variability (HRV) to ascertain if perioperative psychological and music interventions can affect overall anxiety levels.

Materials and Methods

Fourty elderly patients undergoing elective surgery were randomized to two groups; one group received psychological and music intervention, and the other was the control. The intervention group underwent psychological intervention and listening to music for 30 min before surgery.

Results

The mean change in HRV as determined by low frequency (LF) power measurements. After the intervention, the ratio of mean LF to high frequency (HF) power decreased significantly in the intervention group compared to before the intervention (p<0.05). In the control group, mean LF measurements and the ratio of LF:HF did not change significantly. In the intervention group, mean HF power was significantly higher after the procedure than before (p<0.01). Moreover, the mean self-rating anxiety score of the intervention group decreased after the procedure compared to before (p<0.05). The mean visual analogue score of the intervention group 6 hours after surgery was significantly lower than that of the control group (p<0.01).

Conclusion

Perioperative psychological and music interventions can reduce anxiety and postoperative pain in elderly patients.     

Surplus dietary tryptophan inhibits stress hormone kinetics and induces insulin resistance in pigs

Recently we have shown that surplus dietary tryptophan (TRP) reduced the plasma concentrations of cortisol and noradrenaline in pigs. Stress hormones are known to affect insulin sensitivity and metabolism. We now investigated the long-term effects of surplus dietary TRP on 1) plasma and urinary stress hormone kinetics, 2) insulin sensitivity for glucose and amino acid clearance, and 3) whole body nitrogen balance. Pigs were fed for 3 weeks a high (13.2%) vs normal (3.4%) TRP to large neutral amino acids (LNAA) diet, leading to reduced fasting (14 h) plasma cortisol (17.1 ± 3.0 vs 28.9 ± 4.3 ng/mL, p < 0.05) and noradrenaline (138 ± 14 vs 225 ± 21 pg/mL, p < 0.005) concentrations, lower daily urinary noradrenaline (313 ± 32 vs 674 ± 102 ng/kg day, p < 0.001) and adrenaline (124 ± 13 vs 297 ± 42 ng/kg day, p < 0.001) but higher dopamine (5.8 ± 0.5 vs 1.5 ± 0.2 µg/kg day, p < 0.001) excretions, respectively. Insulin sensitivities for both glucose and amino acid clearance, (as measured by the intraportal hyperinsulinaemic (1 mU/kg min) euglycaemic euaminoacidaemic clamp technique), were lower by 22% in pigs on the high vs normal TRP/LNAA diet (14.8 ± 1.4 vs 18.9 ± 0.9, p < 0.05 and 69.7 ± 4.3 vs 89.7 ± 6.8 mL/kg min, p < 0.05, respectively) without affecting urinary nitrogen excretion (35.5 ± 1.0 vs 36.6 ± 1.0% of dietary nitrogen intake, p = ns). In conclusion, long-term feeding of surplus dietary TRP inhibits both baseline adrenocortical and sympathetic nervous system activity, it induces insulin resistance for both glucose and amino acid clearance but it does not affect whole body protein catabolism. This indicates that the bioactive amino acid TRP contributes to homeostasis in neuroendocrinology and insulin action and that low baseline adrenocortical and sympatho-adrenal axis activity are associated with insulin resistance.     

Maternal stress and hair cortisol among pregnant women following hurricane Florence

Natural disasters represent major stressors, resulting in psychological distress and physiological responses such as increased cortisol. During pregnancy, this impacts not only maternal well-being, but also fetal development. In 2018, Hurricane Florence caused extensive damage across the eastern United States. Studies indicated that compared to married pregnant women, unmarried pregnant women had higher risk of distress. Here we assess hair cortisol among a subsample of participants, and variations based on marital status.

Methods

We analyzed multiple stress measures among 37 participants who were pregnant during Hurricane Florence. We used questionnaires modeled on previous studies to assess hardship associated with the hurricane, psychological distress, sociodemographic characteristics, social support, and food security. We analyzed cortisol concentrations in proximal and distal hair sections, representing stress around the time of the disaster (distal) and 3–4 months following the disaster (proximal). We used linear regression to test relationships between hair cortisol and self-report stress measures, and variations based on marital status.

Results

Self-report measures of distress and hardship were similar among married and unmarried participants. Mean cortisol levels in distal and proximal sections were higher among unmarried participants. Controlling for confounding variables, hardship was not associated with hair cortisol. Distress predicted cortisol in distal sections (β = .482, p = .018), with a trend for proximal sections (β = .368, p = .055). Marital status was a significant predictor of distal (β = .388, p = .027) and proximal (β = .333, p = .047) hair cortisol, explaining 8.6%–11.7% of unique variance.

Conclusions

Preexisting and intersecting risk factors likely place unmarried pregnant individuals at risk of stress during and following a disaster.