Endocannabinoids and Heart Rate Variability Alterations after Exposure to Prolonged Intensive Physical Exercise of the Hellenic Navy SEALs

Background: Recent research indicates that both endocannabinoids (eCB) and heart rate variability (HRV) are associated with stress-induced experiences. However, these underlying mechanisms are not elucidated. The present study aims to investigate whether exposure to acute and chronic stress conditions can give rise to measurable changes, both to the peripheral eCB ligands and HRV. Methods: Thirteen candidates under intense preparation for their enlistment in the Hellenic Navy SEALs (HNS) participated in the study. All subjects underwent mental state examination, while HRV variables in time and frequency domain recordings were acquired. Furthermore, at baseline and 30 days after prolonged and intensive physical exercise, hair was collected to measure eCB ligands, such as anandamide (AEA), 2-arachidonoylglycerol (2-AG), and the N-acyl ethanolamine (NAE) molecules: palmitoylethanolamide (PEA) and oleoylethanolamide (OEA). Results: Comparing basal hair concentrations of eCB ligands before and after intense physical exercise, we found that AEA, PEA, and OEA were notably increased, whereas no differences were observed regarding the ligand 2-AG. Furthermore, there were observed associations between the concentrations of peripheral eCB ligands, both at baseline and after the prolonged physical exercise and the time and frequency domains of HRV. Conclusions: These findings suggest that endocannabinoid–HRV interrelations might share a short-term, and long-term adaptability of the changes in self-regulation associated with stress. Further studies will be required to determine the validity of peripheral eCB signaling and HRV as a biomarker for different aspects of the stress response.

Assessment of Resilience of the Hellenic Navy Seals by Electrodermal Activity during Cognitive Tasks

Stress resilience plays a key role in task performance during emergencies, especially in occupations like military special forces, with a routine consisting of unexpected events. Nevertheless, reliable and applicable measurements of resilience in predicting task performance in stressful conditions are still researched. This study aimed to explore the stress response in the Hellenic Navy SEALs (HN-SEALs), using a cognitive–physiological approach. Eighteen candidates under intense preparation for their enlistment in the HN-SEALs and 16 healthy controls (HCs) underwent Stroop tests, along with mental-state and personality examination. Simultaneously, electrodermal activity (EDA) was assessed during each one of cognitive testing procedures. Compared to healthy control values, multiple components of EDA values were found decreased (p < 0.05) in the HN-SEALs group. These results were associated with an increase in resilience level in the HN-SEALs group, since a restricted sympathetic reactivity according to the reduced EDA values was observed during the stressful cognitive testing. This is the first report providing physiological measurements of the sympathetic response of HN-SEALs to a stressful situation and suggests that EDA turns out to be a simple and objective tool of sympathetic activation and it may be used as a complementary index of resilience in HN-SEALs candidates.

The Influence of Brand Image, Service Quality, and Social Media Marketing on Purchase Decision at Restaurant Navy Seals Surabaya

Restaurant Navy Seals Surabaya has many determinants in purchasing decisions, these factors are Brand Image, Service Quality, Social Media Marketing. And these factors will be examined statistically which aims to determine how much influence. The variables used are four, namely Brand Image (X1), Service Quality (X2), Social Media Marketing (X3), and Purchase Decision (Y). Data collection was obtained from distributing questionnaires to customers of Restaurant Navy Seals Surabaya. The results show that the Brand Image variable (X1), Service Quality (X2), and Social Media Marketing (X3) simultaneously and partially have a significant effect on Purchase Decision (Y). This research is a quantitative study with a sample of 160 respondents. The analysis technique used is multiple linear regression analysis. Based on this research, Restaurant Navy Seals Surabaya can maintain Brand Image, Service Quality, and Social Media Marketing, so that customers survive and faithfully buy at the place.

Resilience of The Hellenic Navy Seals Assessed by Heart Rate Variability During Cognitive Tasks

Background The interaction between high physical performance under extreme conditions and the simultaneous control of the cognitive executive functioning has been a subject of research in literature for the past few decades. Stroop test and Heart-rate variability (HRV), have been verified as a valuable clinical tool for the assessment of cerebral and autonomic/ cardiovascular stress responses respectively. Objective The investigation of HRV adaptive response to stress and cognitive stress resilience under strenuous conditions. Methods 34 subjects were enrolled (n = 34). Of them, 18 were candidates under intense preparation for their enlistment in the Hellenic Navy SEALs (H.N.S.) and 16 were healthy controls, matched for sex and similar in age and demographics. All subjects underwent standard Color Word Stroop Testing, arithmetic stroop testing and emotional stroop testing, along with mental state and personality examination with the use of Symptom Checklist 90 Revised (SCL-90R) scl-90 and Eysenck Personality Questionnaire (EPQ), respectively. HRV variables in time and frequency domains recordings were acquired, during each aforementioned cognitive testing procedure. Results Our results showed that H.N.S.’s performance on both cognitive and emotion stroop tasks (p ≥ 0.054 for all cognitive and emotion stroop tasks’ features) was equivalent to controls even though they exhibited statistically significant lower levels of HRV in different time (ranged from p < 0.01 to p < 0.05) and frequency domain variables (ranged from p < 0.01 to p < 0.05). Finally, in a between group comparison of the psychometric tools, O.Y.K.s had significantly higher somatization, anxiety and neuroticism than controls. Conclusion In conclusion, these findings indicate flexible autonomic regulation (HRV) supports recovery following challenge during cognitive and emotional tasks (stroop tests), which in turn supports problem solving or adaptability skills. HRV measurement begins to be a sophisticated and relevant tool for both scientific and clinical insights, promising to be an index regarding the psychophysiological resilience especially in the neurovisceral integration (NVI) model. However further longitudinal research on the field is required.