Impact of L-theanine and L-tyrosine on markers of stress and cognitive performance in response to a virtual reality based active shooter training drill.

Ingestion of L-theanine and L-tyrosine has been shown to reduce salivary stress biomarkers and improve aspects of cognitive performance in response to stress. However, there have been no studies to concurrently examine the impact of both L-theanine and L-tyrosine ingestion during a mental stress challenge (MSC) involving a brief cognitive challenge and a virtual reality based active shooter training drill. Thus, the purpose of this study was to determine the impact of ingestion of L-theanine and L-tyrosine on markers of stress and cognitive performance in response to a virtual reality active shooter drill and cognitive challenge. The cognitive challenge involved a Stroop challenge and mental arithmetic. Eighty subjects (age = 21 ± 2.6 yrs; male = 46; female = 34) were randomly assigned L-tyrosine (n = 28; 2000 mg), L-theanine (n = 25; 200 mg), or placebo (n = 27) prior to MSC exposure. Saliva samples, state-anxiety inventory (SAI) scales, and heart rate (HR) were collected before and after exposure to the MSC. Saliva was analyzed for stress markers α-amylase (sAA) and secretory immunoglobulin A (SIgA). The MSC resulted in significant increases in sAA, SIgA, HR, and SAI. Ingestion of L-theanine and L-tyrosine did not impact markers of stress. However, the L-tyrosine treatment demonstrated significantly lower missed responses compared to the placebo treatment group during the Stroop challenge. These data demonstrate that ingestion of L-theanine or L-tyrosine does not impact markers of stress in response to a MSC but may impact cognitive performance. This study was pre-registered as a clinical trial ("Impact of supplements on stress markers": NCT05592561).

Interviewing and interrogation practices and beliefs, 20 years later: A national self-report survey of American police.

OBJECTIVE: This survey examined current law enforcement beliefs and practices about interviewing and interrogation to gauge whether they have evolved given the research and training developed over the past 20 years. HYPOTHESES: We hypothesized that police beliefs and practices would have evolved along with research findings over the past 20 years. METHOD: We surveyed 526 law enforcement officers about the practices and beliefs regarding interviewing and interrogation. We asked questions about officers' beliefs about rates of true and false confessions, time spent in the interrogation room, beliefs about their ability to detect deception, training experience, practices of recording interrogations, and their self-reported use of interrogation techniques. RESULTS: Overall, when we compared our survey with Kassin et al.'s (2007) seminal survey, we found both similar results and evolving positive trends. The average interview was reportedly 1.6 hr, virtually no different from that in Kassin and colleagues' study. In addition, our sample reported that 26.2% of innocent suspects at least partially falsely confessed. Further, whereas Kassin and colleagues found that fewer than one in 10 interrogations were video recorded, we found that now more than half of interrogations are recorded in this way. CONCLUSIONS: In a geographically diverse sample of U.S. law enforcement officers, we found significant positive trends toward knowledge and practices informed by research generated over the past decades on interviewing and interrogation. Although causality could not be determined, these findings indicate an evolution of the U.S. law enforcement mindset in a more science-based direction. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Virtual Reality Based Active Shooter Training Drill Increases Salivary and Subjective Markers of Stress.

Law enforcement personnel are required to respond to a variety of dangerous, potentially life-threatening high stress scenarios. Virtual reality (VR)-based training has been shown to attenuate stress responses; however, little is known about the acute stress response from VR exposure. This study examined the impact of participating in a VR-based active shooter training drill (ASD) on markers of physiological stress as well as potential differences in men and women. To examine the impact of participation in a ~50 sec VR-based ASD, 29 subjects (n = 29; 17 males, 12 females) participated in a quasi-experimental single group design. Saliva samples were collected and analyzed from 27 of the 29 subjects a total of four times 1) 30-min prior to, 2) 5-min prior to, 3) 5-min after, and 4) 30-min after the ASD and analyzed for α-amylase (AA) activity and concentrations of secretory immunoglobulin-A (SIgA), cortisol (CORT), and uric acid (UA). Participation in the ASD resulted in a significant (p < 0.05) increase in salivary stress markers AA and SIgA. In addition, lower concentrations of CORT and UA were found in women compared to men. These findings have implications for law enforcement and/or military personnel that may seek to implement a VR-based training into their training regimen. Future studies should investigate the impact of longitudinal participation in ASD interventions to determine if this is an effective training method to reduce stress responses to real life active shooter training drills.

Stress response to virtual reality based active shooter training: Impact of caffeine consumption.

Participation in a virtual reality based active shooter training drill (VR-ASD) has been shown to increase biomarkers of stress; however, the impact of caffeine consumption on this response has not been studied. Caffeine ingestion has been shown to have favorable effects on physical and cognitive performance among athletic and tactical occupations alike. This study examined the impact of caffeine ingestion on subjective and physiological markers of stress in response to a mental stress task (MST) which involved participation in a VR-ASD and cognitive challenge consisting of mental arithmetic and a Stroop challenge. Fifty-three subjects were randomly assigned either caffeine (n = 26) or placebo (n = 27) prior to being exposed to the MST. Saliva samples, heart rate (HR), and state-anxiety inventory (SAI) scales, were collected before and after exposure to the MST. Saliva was analyzed for α-amylase (sAA), secretory IgA (SIgA), and cortisol (sCORT) concentrations. The MST resulted in significant increases in sAA, SIgA, HR, and SAI. Immediately post MST, sAA concentrations were significantly higher following the caffeine treatment compared to placebo. These data demonstrate that caffeine consumption results in significantly greater sAA concentrations post MST. This study was pre-registered as a clinical trial ("Impact of supplements on stress markers": NCT05592561).

Risk Factors for Cardiometabolic Disease in Professional Firefighters.

OBJECTIVE: Firefighters are plagued with cardiometabolic disease (CMD). Obesity, poor cardiorespiratory and muscular fitness, and blood lipids (low-density lipoprotein cholesterol, triglycerides, low high-density lipoprotein cholesterol) are risk factors for CMD. However, markers of oxidative stress, inflammation, and insulin resistance can provide further insight regarding CMD risk. METHODS: This study investigated the relationships between fitness metrics (cardiorespiratory and muscular fitness, percent body fat, waist circumference), blood lipids, blood pressure, and years of experience as a firefighter to blood markers of insulin resistance: Homeostatic Model Assessment for Insulin Resistance (HOMA-IR), oxidative stress: advanced oxidation protein products (AOPPs), and inflammation: C-reactive protein. RESULTS: Waist circumference and blood concentrations of triglycerides were significantly related to AOPPs and HOMA-IR. Cardiorespiratory fitness was inversely related to AOPPs, HOMA-IR and C-reactive protein. CONCLUSION: These findings demonstrate the importance of high cardiorespiratory fitness and low waist circumference to reduce markers of CMD.

Firefighters With Higher Cardiorespiratory Fitness Demonstrate Lower Markers of Cardiovascular Disease Risk.

OBJECTIVE: High cardiorespiratory fitness (CRF) is associated with reduced markers of oxidative stress and cardiovascular disease (CVD) risk factors; however, this relationship has not been elucidated in firefighters. The purpose of this study was to examine differences in markers of CVD risk between firefighters who have either high or low levels of CRF. METHODS: Forty-six firefighters participated in a maximal graded exercise test and a dual-energy x-ray absorptiometry scan and provided a fasted blood sample. V˙O 2max values were categorized based on American College of Sports Medicine guidelines to establish high- and low-fitness groups. RESULTS: High fitness firefighters demonstrated significantly higher high-density lipoprotein cholesterol and lower markers of CVD risk: cholesterol, triglycerides, low-density lipoprotein cholesterol, insulin, homeostatic model assessment for insulin resistance, C-reactive protein, and advanced oxidation protein products concentrations. CONCLUSION: Firefighters are encouraged to maintain high CRF to reduce risk of CVD.

Women demonstrate lower markers of stress and oxidative stress during active shooter training drill.

It has been well documented that police officers are frequently engaged in a variety of high stress situations during their normal daily tasks, such as civilian encounters where force is needed or domestic violence situations, that cause significant increases in a variety of physiological and psychological stress markers. Chronic exposure to stressors increases risk for cardiovascular disease (CVD) progression. The purpose of this study was to compare male and female salivary and blood markers of stress in response to an active shooter training drill (ASD) to determine if acute stress differentially impacts men and women to better understand if interventions should be targeted. Thirty-one participants (males â€‹= â€‹15 [mean age: 23], females â€‹= â€‹16 [mean age: 21]) participated in an ASD involving professional actors playing the role of one active gunman, as well as four victims. The ASD lasted approximately 50 seconds. Blood samples were collected 15 â€‹min prior as well as after the ASD and analyzed for epinephrine (EPI), norepinephrine (NE), and hydrogen peroxide (H2O2) levels. Saliva samples were collected 30 and 5 â€‹min prior to the ASD and 5 and 30 â€‹min after the ASD, and were analyzed for cortisol, α-amylase, uric acid, and secretory immunoglobulin-A (SIgA). Our analysis revealed that acute (~50 â€‹sec) psychological stress in the form of an ASD resulted in significant increases in blood and salivary stress and oxidative stress markers in both men and women. However, four of the seven markers were lower in female participants (cortisol, uric acid, H2O2, and α-amylase presented significant main effects for sex). In addition, SIgA was significantly lower in women compared to men 30 â€‹min prior to, and five min post ASD. These findings suggest females may be at a lower risk to stress induced oxidative stress and CVD.

Active Shooter Training Drill Increases Blood and Salivary Markers of Stress.

Police officers are frequently engaged in a variety of high-stress scenarios, such as high-speed chases and other suspect conflicts, that cause significant increases in a variety of physiological and psychological stress markers. The purpose of this study was to investigate salivary and blood markers of stress in response to an active shooter training drill (ASD). Thirty-one participants (n = 31; males = 15, females = 16; Age: 21 ± 3.5 years) participated in an ASD involving professional actors playing the role of one active gunman, as well as four victims. The ASD lasted approximately 50 s. Blood samples were collected 15 min prior as well as after the ASD and analyzed for epinephrine (EPI) and norepinephrine (NE) levels. Saliva samples were collected 30 and 5 min prior to the ASD and 5 and 30 min after the ASD, were analyzed for cortisol, α-amylase, and secretory immunoglobulin-A (SigA). The ASD resulted in significant (p < 0.05) increases in EPI, α-amylase, and SigA levels. The increase in NE from pre to post ASD approached significance (p = 0.06). These results demonstrate that a short duration (~50 s) ASD results in significant increases in both blood and salivary markers of stress. These data may provide meaningful implications for those engaged in high-stress tactical occupations, especially law enforcement and military personnel, as chronic exposure to such occupational stressors can contribute to cardiometabolic disease.