Induction Of Psychological Stress Research Articles

Comparing a Fitbit Wearable to an Electrocardiogram Gold Standard as a Measure of Heart Rate Under Psychological Stress: A Validation Study

Wearable devices collect physiological and behavioral data that have the potential to identify individuals at risk of declining mental health and well-being. Past research has mainly focused on assessing the accuracy and the agreement of heart rate (HR) measurement of wearables under different physical exercise conditions. However, the capacity of wearables to sense physiological changes, assessed by increasing HR, caused by a stressful event has not been thoroughly studied. This study followed 3 objectives: (1) to test the ability of a wearable device (Fitbit Versa 2) to sense an increase in HR upon induction of psychological stress in the laboratory; (2) to assess the accuracy of the wearable device to capture short-term HR variations caused by psychological stress compared to a gold-standard electrocardiogram (ECG) measure (Biopac); and (3) to quantify the degree of agreement between the wearable device and the gold-standard ECG measure across different experimental conditions. Participants underwent the Trier Social Stress Test protocol, which consists of an oral phase, an arithmetic stress phase, an anticipation phase, and 2 relaxation phases (at the beginning and the end). During the stress protocol, the participants wore a Fitbit Versa 2 and were also connected to a Biopac. A mixed-effect modeling approach was used (1) to assess the effect of experimental conditions on HR, (2) to estimate several metrics of accuracy, and (3) to assess the agreement: the Bland-Altman limits of agreement (LoA), the concordance correlation coefficient, the coverage probability, the total deviation index, and the coefficient of an individual agreement. Mean absolute error and mean absolute percent error were calculated as accuracy indices. A total of 34 university students were recruited for this study (64% of participants were female with a mean age of 26.8 years, SD 8.3). Overall, the results showed significant HR variations across experimental phases. Post hoc tests revealed significant pairwise differences for all phases. Accuracy analyses revealed acceptable accuracy according to the analyzed metrics of accuracy for the Fitbit Versa 2 to capture the short-term variations in psychological stress levels. However, poor indices of agreement between the Fitbit Versa 2 and the Biopac were found. Overall, the results support the use of the Fitbit Versa 2 to capture short-term stress variations. The Fitbit device showed acceptable levels of accuracy but poor agreement with an ECG gold standard. Greater inaccuracy and smaller agreement were found for stressful experimental conditions that induced a higher HR. Fitbit devices can be used in research to measure HR variations caused by stress, although they cannot replace an ECG instrument when precision is of utmost importance.

Outpatient Randomized Crossover Automated Insulin Delivery Versus Conventional Therapy with Induced Stress Challenges.

Background: Automated insulin delivery (AID) systems have not been evaluated in the context of psychological and pharmacological stress in type 1 diabetes. Our objective was to determine glycemic control and insulin use with Zone Model Predictive Control (zone-MPC) AID system enhanced for states of persistent hyperglycemia versus sensor-augmented pump (SAP) during outpatient use, including in-clinic induced stress. Materials and Methods: Randomized, crossover, 2-week trial of zone-MPC AID versus SAP in 14 adults with type 1 diabetes. In each arm, each participant was studied in-clinic with psychological stress induction (Trier Social Stress Test [TSST] and Socially Evaluated Cold Pressor Test [SECPT]), followed by pharmacological stress induction with oral hydrocortisone (total four sessions per participant). The main outcomes were 2-week continuous glucose monitor percent time in range (TIR) 70-180 mg/dL, and glucose and insulin outcomes during and overnight following stress induction. Results: During psychological stress, AID decreased glycemic variability percentage by 13.4% (P = 0.009). During pharmacological stress, including the following overnight, there were no differences in glucose outcomes and total insulin between AID and physician-assisted SAP. However, with AID total user-requested insulin was lower by 6.9 U (P = 0.01) for pharmacological stress. Stress induction was validated by changes in heart rate and salivary cortisol levels. During the 2-week AID use, TIR was 74.4% (vs. SAP 63.1%, P = 0.001) and overnight TIR was 78.3% (vs. SAP 63.1%, P = 0.004). There were no adverse events. Conclusions: Zone-MPC AID can reduce glycemic variability and the need for user-requested insulin during pharmacological stress and can improve overall glycemic outcomes. Clinical Trial Identifier NCT04142229.

Effect of Honey on Orthodontic Tooth Movement and Osteoclastic Activity in Psychologically Stressed Animals

Introduction: Orthodontics is a clinical specialty in dentistry related to the correction of dentofacial deformities. Psychological stress factors delay Orthodontic tooth movement (OTM). Honey can be considered a useful and harmless natural product to reduce stress levels, hence improves the efficacy of OTM.
 Aims & Objectives: To compare the differences in the rate of tooth movement and osteoclastic activity between control, psychologically stressed and honey treated psychologically stressed groups after 1 week of orthodontic force application in an animal model.
 Place and duration of study: This experimental study was conducted at the animal research laboratory and Histopathology Department of Post Graduate Medical Institute (PGMI), Lahore, Pakistan, from April 2019 to June 2020.
 Material & Methods: Thirty-six Sprague Dawley rats were randomly divided into A, B and C groups. Psychological Stress was induced in group A (PS group) while Honey was given orally as a therapeutic agent along with induction of psychological stress in group B (PSH group), and group C was the Control Group. Statistical analyses were performed using SPSS version 24 software. The quantitative variables were the orthodontic tooth movement, the osteoclast count, and the expression of RANKL. One-way ANOVA was applied to calculate the mean difference and Post hoc Tukey test applied for multiple comparisons among the groups. A p-value ? 0.05 was considered statistically significant in all 3 groups.
 Results: There was a significant difference (p-value <0.05) between control and experimental groups in the orthodontic tooth movement and levels of RANKL, however, there was no significant difference between PS and PSH groups.
 Conclusion: Psychological stress delays orthodontic tooth movement by causing a reduction in its rate and osteoclastic activity and honey has no significant correlation with lowering stress levels, hence does not improve orthodontic tooth movement efficiency.

Animal Models of Temporomandibular Disorder.

Temporomandibular disorders (TMD) are a group of diseases in the oral and maxillofacial region that can manifest as acute or chronic persistent pain, affecting millions of people worldwide. Although hundreds of studies have explored mechanisms and treatments underlying TMD, multiple pathogenic factors and diverse clinical manifestations make it still poorly managed. Appropriate animal models are helpful to study the pathogenesis of TMD and explore effective treatment measures. At present, due to the high cost of obtaining large animals, rodents and rabbits are often used to prepare TMD animal models. Over the past decade, various animal models have been intensively developed to understand neurobiological and molecular mechanisms of TMD, and seek effective treatments. Although these models cannot carry out all clinical features, they are valuable in revealing the mechanisms of TMD and creating curative access. Currently, there are multitudinous animal models of TMD research. They can be constructed in different means and summarized into four ways according to the various causes and symptoms, including chemical induction (intra-articular injection of ovalbumin, collagenase, formalin, vascular endothelial growth factor, intramuscular injection of complete Freund’s adjuvant, etc.), mechanical stress stimulation (passive mouth opening, change of chewing load), surgical operation (partial disc resection, joint disc perforation) and psychological stress induction. Here, we summarize and discuss different approaches of animal models for determining neurophysiological and mechanical mechanisms of TMD and assess their advantages and limitations, respectively.

Synergistic Effects of Chronic Restraint-Induced Stress and Low-Dose 56Fe-particle Irradiation on Induction of Chromosomal Aberrations in Trp53-Heterozygous Mice.

Astronauts can develop psychological stress (PS) during space flights due to the enclosed environment, microgravity, altered light-dark cycles, and risks of equipment failure or fatal mishaps. At the same time, they are exposed to cosmic rays including high atomic number and energy (HZE) particles such as iron-56 (Fe) ions. Psychological stress or radiation exposure can cause detrimental effects in humans. An earlier published pioneering study showed that chronic restraint-induced psychological stress (CRIPS) could attenuate Trp53 functions and increase carcinogenesis induced by low-linear energy transfer (LET) γ rays in Trp53-heterozygous (Trp53+/-) mice. To elucidate possible modification effects from CRIPS on high-LET HZE particle-induced health consequences, Trp53+/- mice were received both CRIPS and accelerated Fe ion irradiation. Six-week-old Trp53+/- C57BL/6N male mice were restrained 6 h per day for 28 consecutive days. On day 8, they received total-body Fe-particle irradiation (Fe-TBI, 0.1 or 2 Gy). Metaphase chromosome spreads prepared from splenocytes at the end of the 28-day restraint regimen were painted with the fluorescence in situ hybridization (FISH) probes for chromosomes 1 (green), 2 (red) and 3 (yellow). Induction of psychological stress in our experimental model was confirmed by increase in urinary corticosterone level on day 7 of restraint regimen. Regardless of Fe-TBI, CRIPS reduced splenocyte number per spleen at the end of the 28-day restraint regimen. At 2 Gy, Fe-TBI alone induced many aberrant chromosomes and no modifying effect was detected from CRIPS on induction of aberrant chromosomes. Notably, neither Fe-TBI at 0.1 Gy nor CRIPS alone induced any increase in the frequency of aberrant chromosomes, while simultaneous exposure resulted in a significant increase in the frequency of chromosomal exchanges. These findings clearly showed that CRIPS could enhance the frequency of chromosomal exchanges induced by Fe-TBI at a low dose of 0.1 Gy.

Acute Exercise, Psychological Stress Induction, and Episodic Memory.

Objective: In this study, we evaluated whether exercise prior to memory encoding or during memory consolidation can influence episodic memory function after being exposed to a stressful environment. Methods: We conducted 3 between-group randomized controlled experiments among young adults. We assessed episodic memory (via logic memory task) at the beginning of the experiment and approximately 45 minutes later. Across the 3 experiments, we varied the temporal period (eg, before memory encoding or during consolidation) of the acute bout of exercise (15-minute moderate-intensity exercise) and psychological stress induction. Results: Across all 3 experiments there was a statistically significant main effect for time for memory function, but there were no time x group interaction effects. Conclusion: Memory declined across the 2 assessment periods, but for all 3 experiments, exercise was not associated with memory function after being exposed to a stressful stimulus.

The effect of stress on customer perception of the frontline employee: an experimental study

This article examines positive effects of customer stress drawn upon the theory of excitation transfer. Contrary to previous marketing and management literature, the present study focuses on positive outcomes of stress based on a study by Dutton and Aron (J Pers Soc Psychol 30(4):510–517, 1974), who found increasing interpersonal attraction in stressful situations in a private context. The present study examines whether these findings can be applied to a service context and how interpersonal liking affects customer’s employee perception and customer-related responses. An experimental laboratory study (N = 104), including a service-employee interaction and a psychological stress induction (Social Evaluative Cold-Water Pressure Test [SECPT]), was conducted. Results indicate a positive effect of stress on relationship quality constructs (relationship trust, commitment, satisfaction, and relationship investment) and partially on behavioral constructs, fully mediated by the customer’s interpersonal liking of the service employee. The present research contributes to marketing and management literature in two ways: it highlights (a) the importance of context and emotion for the perception of the employee, and (b) the relevance of interpersonal liking of the service employee for the long-term customer relationship.

Participation of Antidiuretic Hormone (ADH) in Asthma Exacerbations Induced by Psychological Stress via PKA/PKC Signal Pathway in Airway-Related Vagal Preganglionic Neurons (AVPNs)

Aims: Present study was performed to examine whether ADH was implicated in psychological stress asthma and to explore the underlying molecular mechanism. Methods: We not only examined ADH levels in the cerebrospinal fluid (CSF) via radioimmunoassay, but also measured ADH receptor (ADHR) expression in airway-related vagal preganglionic neurons (AVPNs) through real-time PCR in all experimental mice. Western blotting was performed to evaluate the relationship between ADH and PKA/PKC in psychological stress asthma. Finally, the role of PKA/PKC in psychological stress asthma was analyzed. Results: Marked asthma exacerbations were noted owing to significantly elevated levels of ADH and ADHR after psychological stress induction as compared to OVA alone (asthma group). ADHR antagonists (SR-49095 or SR-121463A) dramatically lowered higher protein levels of PKAα and PKCα induced by psychological stress as compared to OVA alone, suggesting the correlation between ADH and PKA/PKC in psychological stress asthma. KT-5720 (PKA inhibitor) and Go-7874 (PKC inhibitor) further directly revealed the involvement of PKA/PKC in psychological stress asthma. Some notable changes were also noted after employing PKA and PKC inhibitors in psychological stress asthma, including reduced asthmatic inflammation (lower eosinophil peroxidase (EPO) activity, myeloperoxidase (MPO) activity, immunoglobulin E (IgE) level, and histamine release), substantial decrements in inflammatory cell counts (eosinophils and lymphocytes), and decreased cytokine secretion (IL-6, IL-10, and IFN-γ), indicating the involvement of PKA/PKC in asthma exacerbations induced by psychological stress. Conclusion: Our results strongly suggested that ADH participated in psychological stress-induced asthma exacerbations via PKA/PKC signal pathway in AVPNs.

Role of oxidative stress in anxiety‐like behavior and learning and memory impairment in a rat model of social stress

Recently, we reported that direct pharmacological induction of oxidative stress causes anxiety‐like behavior and learning and memory impairment in a rodent model of oxidative stress (OS). In the present study, we tested whether induction of psychological stress using an established rat model of social stress leads to the same consequences i.e increased OS, anxiety and learning and memory impairment in rats. To test this hypothesis, a modified version of the resident‐intruder model for social stress (SS) was used. Sprague Dawley rats were randomly assigned to either SS or control exposure for 30 min for seven consecutive days. SS exposure resulted in intruder subordination, termed defeat, and was operationally defined by the intruder assuming a supine posture that was held for approximately 3 s. Controls were placed in a novel cage behind a partition for 30 min daily. At the end of the social defeat protocol, body weights, food and water intake were recorded, anxiety‐like behavior (open‐field and light‐dark) as well as learning‐memory (radial water maze) tests were conducted. We observed a significant decrease in the body weight in the SS rats as compared to the controls. Furthermore, social stress increased anxiety‐like behavior and caused learning and memory impairment of SS rats as compared to the control group. Biochemical data suggests involvement of oxidative stress mechanisms in these behaviors. NIH R15G103327

Associations between open-field behaviour and stress-induced hyperthermia in two breeds of sheep

AbstractIn sheep(Ovis aries)and other farm animals, routine husbandry procedures can cause negative emotions, such as fear, which are generally considered to reduce animal welfare. The open-field test (OFT) is the most widely used test to measure fearfulness in animals. The induction of psychological stress is often accompanied by an elevation of core body temperature, referred to as stress-induced hyperthermia (SIH) and both OFT and SIH were used in this study to measure fearfulness in sheep: the aim being to examine associations between behaviour in the OFT and the SIH response, using data from two breeds of sheep tested repeatedly over time. Twentyfour ewes from two breeds, Lacaune and Ripollesa, were tested for 10 min with all behaviours recorded throughout. Rectal temperature was measured immediately prior to the start of the test (T1) and 10 min after its completion (T2). SIH was measured as the difference between T2 and T1. Sheep were tested over three periods of three experimental days each. Ewes of both breeds showed consistent changes in behaviour in the OFT and a clear SIH response. Bleats and visits to the water bucket showed a clear pattern between rounds. Differences between T1 and T2 were found, T2 was higher than T1 suggesting that exposure to a novel arena caused SIH. Breed differences were found whereby T2 was 0.12°C higher in Ripollesa than Lacaune. These findings have implications for selection programmes, creating the possibility of selecting less fearful animals that will cope better with handling procedures that may induce fear. Further, they also demonstrate the importance of using both behavioural and physiological variables to evaluate fear.

Physiological stress exacerbates murine colitis by enhancing proinflammatory cytokine expression that is dependent on IL-18

Psychological stress is an environmental factor considered to be a precipitating factor of inflammatory bowel disease. Interleukin (IL)-18 plays a role in stress-induced aggravation in some diseases. The aim of this study was to establish a model of murine colitis exacerbated by psychological stress and to clarify the role of IL-18 in this model. Male C57Bl/6 mice and IL-18(-/-) mice were used for this study. The mice received dextran sulfate sodium (DSS) for induction of colitis. Some mice were exposed to psychological stress using a communication box. Body weight, colonic length, and histological inflammation were measured for assessment of colitis. Tumor necrosis factor (TNF)-α and IL-18 expression in the colon and IL-18 expression in the adrenal gland were analyzed using real-time PCR. The effect of anti-IL-18 antibody was also investigated. Effects of TNF-α and IL-18 on cytokine expressions were studied using the colonic epithelial cell line LS174T. Induction of psychological stress in DSS-treated wild-type mice significantly exacerbated colitis with enhanced expression of proinflammatory cytokines and IL-18. However, induction of psychological stress in DSS-treated IL-18(-/-) mice did not aggravate colitis compared with that in the IL-18(-/-) group given only DSS treatment. Stress-induced aggravation of colitis was ameliorated significantly by anti-IL-18 antibody treatment. IL-18 did not enhance TNF-α-induced expression of intercellular adhesion molecule-1 or IL-8 in LS174T. We established a model of colitis exacerbated by psychological stress. Psychological stress enhanced IL-18 expression and plays a proinflammatory role in stress-induced aggravation of colitis.

Gender Influences the Core Temperature Response to a Simulated Open Field in Adult Guinea Pigs

The induction of psychological stress is often accompanied by a transient increase in core temperature, commonly referred to as stress induced hyperthermia. Although stress-induced hyperthermia occurs when rats, mice, and pigs are exposed to a novel stimulus (e.g., a simulated open field, restraint, etc.), whether or not it occurs in guinea pigs has not been investigated. The present experiments were therefore carried out to investigate the thermoregulatory responses of both male ( n = 7) and female ( n = 7) adult guinea pigs when they were exposed to a simulated open field. Unexpectedly, neither the male nor female guinea pigs developed stress-induced hyperthermia. To the contrary, female but not male guinea pigs significantly decreased their core temperature during an open field experiment. The mechanism of the gender-specific thermoregulatory response of the adult guinea pig to psychological stress is presently unknown.

Coordination of autonomic and behavioral thermoregulatory responses during exposure to a novel stimulus in rats.

The induction of psychological stress in rats is accompanied by an elevation of core temperature. Our experiments were carried out to determine whether the latency, duration, magnitude, or effector mechanisms of the core temperature response to psychological stress would be altered when rats were allowed to use behavioral as well as autonomic thermoregulation. Core temperature, oxygen consumption, and ambient temperature were measured in adult rats before and after handling and a sham intraperitoneal injection. Seven rats were studied in a thermocline (gradient of 7 to 42 degrees C) and eight rats were studied in a metabolic chamber (25 degrees C). The rats studied in the thermocline selected a warm ambient temperature following the sham intraperitoneal injection and exhibited an increase in core temperature of shorter latency, greater magnitude, and greater duration than those studied in the metabolic chamber. The rats studied in the metabolic chamber exhibited an oxygen consumption response of greater magnitude and duration than the animals studied in the thermocline. Thus the characteristics in addition to the effector mechanisms of the core temperature response to psychological stress are altered when rats are allowed to use behavioral as well as autonomic thermoregulatory effectors.