Combat Stress Decreases Memory of Warfighters in Action

An Examination of Subjective and Objective Measures of Stress in Tactical Populations: A Scoping Review

Persons working in tactical occupations are often exposed to high-stress situations. If this stress is to be measured, an understanding of the stress outcomes used in these occupations is needed. The aim of this review was to capture and critically appraise research investigating subjective and objective outcome measures of physiological stress in tactical occupations. Several literature databases (PubMed, EMBASE, EBsco) were searched using key search words and terms. Studies meeting inclusion criteria were critically evaluated and scored by two authors using the Joanne Briggs Institute (JBI) critical appraisal tool. Of 17,171 articles, 42 studies were retained. The Cohen's Kappa agreement between authors was 0.829 with a mean JBI Score of included studies of 8.1/9 ± 0.37 points. Multiple subjective and objective measures were assessed during a variety of high-stress tasks and environments across different occupations, including police officers, emergency service personnel, firefighters, and soldiers in the military. Common objective outcomes measures were heart rate, cortisol, and body temperature, and subjective measures were ratings of perceived exertion, and the Self Trait Anxiety Inventory. Often used in combination (i.e., subjective and objective), these outcome measures can be used to monitor stressors faced by tactical personnel undergoing on-the-job training.

PECULIARITIES OF FORMATION OF CADETS' PSYCHOLOGICAL RESILIENCE AND PHYSICAL READINESS FOR COMBAT STRESS

OBJECTIVE

The aim: To investigate the impact of special physical training sessions on the formation of cadets' psychological resilience and physical readiness for the stress factors of future professional and combat activities.

PATIENTS AND METHODS

Materials and methods: The research involved 96 cadets (men) in the 2nd training year of S. P. Koroliov Zhytomyr Military Institute (Ukraine) aged 18-20 years, who were divided into two groups: the experimental (E, n = 47) and the control (C, n = 49). The cadets of the E group studied according to the authors' program, and the C group cadets - according to the existing program. Cadets' psychological resilience was studied using psycho-diagnostic methods aimed at assessing their volitional qualities. Cadets' physical fitness was assessed by the tests of general and special physical training.

RESULTS

Results: It was found that the level of general physical training of the E and the C group cadets was significantly the same (p > 0.05) at the end of the research but in terms of special physical training and psychological readiness, the E group cadets had all indicators significantly (p < 0.05-0.001) better than those of the C group.

CONCLUSION

Conclusions: It has been proved that the special physical training sessions conducted according to the authors' program were more effective than the existing program in forming cadets' physical readiness and psychological resilience for stress factors of future professional and combat activities.

Psychophysiological Stress Response of Novel Students in Chemical Laboratory Practices

Abstract. The aim of the present study was to analyze the psychophysiological stress response of novel pharmacy and biotechnology students in chemistry laboratory practices. Autonomic stress response was analyzed in 66 students by considering heart rate variability (HRV) values before, during, and after their first laboratory practice, as well as their distress perception before and after this activity. In the laboratory practice, students had to deal with toxic products, sharp objects, or irritating substances while being examined by the teachers. Consistent with a large anticipatory anxiety response at the beginning of the practice, results showed low HRV values, generally related to a typical sympathetic modulation. This sympathetic effect persisted during the entire laboratory practice. Moreover, just after the end of the practice, there was an attenuation of the sympathetic activation and a takeover by the parasympathetic system, as revealed by the increase of HRV parameters. Laboratory practices performed by novel Pharmacy and Biotechnology students did not produce the expected habituation response at psychophysiological level since, in addition to an anticipatory anxiety response observed prior to the laboratory practice, a high sympathetic autonomic activation was observed during the whole practice. In brief, using HRV parameters could be a useful tool to analyze stress responses in students and to help them with new strategies to improve routine evaluation procedures.

Advances in the understanding and enhancement of the human cognitive functions of learning and memory

Learning and memory are among the key cognitive functions that drive the human experience. As such, any defective condition associated with these cognitive domains could affect our navigation through everyday life. For years, researchers have been working toward having a clear understanding of how learning and memory work, as well as ways to improve them. Many advances have been made, as well as some challenges that have also been faced in the process. That notwithstanding, there are prospects with regards to the frontier of the enhancement of learning and memory in humans. This review article selectively highlights four broad areas of focus in research into the understanding and enhancement of learning and memory. Brain stimulation, effects of sleep, effects of stress and emotion, and synaptic plasticity are the main focal areas of this review, in terms of some pivotal research works, findings and theories.

Relationship between Physical Fitness and Academic Performance in University Students

Several studies involving students have been developed with the objective to analyse the influence of different factors on academic performance. Nevertheless, all these studies were focused on stress and sympathetic modulation response instead of contemplating other physiological parameters that may affect academic performance. The aim of the present study was to analyse body composition, cardiovascular, sleep habits and physical activity factors related to the academic performance of university students. Two hundred and sixty-one students with bachelor's degrees in physical activity and sports science participated in the present study (age: 22.49 ± 3.84 years; weight: 73.94 ± 11.4 kg; height: 176.28 ± 7.68 cm; 87.7% males). Participants were divided into two groups according to their academic performance: low academic performance group (LAPG) and high academic performance group (HAPG). Body composition, blood pressure, physical activity and sleep habits were measured, and maximum oxygen uptake was estimated by the Cooper's 12 min run test. The results show that students with a high academic performance presented a higher VO₂ max than the LAPG (LAPG = 40.32 ± 6.07; HAPG = 47.91 ± 6.89 mL/kg/min; p < 0.001), as well as lower diastolic blood pressure (LAPG = 72.44 ± 14.27; HAPG = 67.48 ± 13.50 mmHg; p < 0.01) and insomnia levels caused by breathing problems (LAPG = 0.37 ± 0.8; HAPG = 0.13 ± 0.42 a.u.; p = 0.046). Therefore, we found a relevant association between academic performance and VO₂ max, diastolic blood pressure, and insomnia caused by breathing problems. These results highlight the importance of applying different programmes that may improve these factors, especially those related to physical activity and sleep habits in order to improve academic achievement.

Psychophysiological Stress Status of Soldiers Prior to an Operative Deployment

An anticipatory stress response develops before an internal or external stimulus, which initiates a homeostasis process through a chain of responses that enable human organisms to face different threats, thus allowing them to adapt to a continuous and eliciting environment. In the current research, we analyzed the psychophysiological anticipatory anxiety response of professional soldiers prior to a real mission in an actual theater of operation. Autonomic modulation through the heart rate variability values, muscular strength manifestation, and psychological stress of 53 military personnel of Army Airmobile Forces (age: M = 35.4 years, SD = 5.88 years; height: M = 1.75 m, SD = 6.87 cm; body mass: M = 77.33 kg, SD = 11.95 kg; military duty = 14.44 years, SD = 6.43; military operation experience = 4 months, SD = 4.25 months) and a control group of 33 civil participants were analyzed. The military personnel presented significant differences in some HRV values related to the activation of sympathetic systems. We found that the military personnel presented an anticipatory anxiety response only at an autonomic level, showing an increased sympathetic modulation, but not at a psychological level, since their anxiety levels were not significantly different than those of the control civilians. In addition, this anticipatory anxiety response did not affect muscular strength manifestation, as it presented no significant differences between the military personnel and the control group.

Are Crohn's Disease Patients Limited in Sport Practise? An UltraEndurance Case-Control Study Response

The aim of this study was to analyze the psychophysiological response of a Crohn's Disease patient in an ultra-endurance event. The psychophysiological responses of a Crohn's Disease and non-Crohn's Disease participant were analysed before during and after an 8 h ultra-endurance running event. Results showed how Crohn's patient presented a similar psychophysiological response than non-Crohn's participant in the ultra-endurance event, except for a higher pre- and post-event sympathetic modulation, lower event sympathetic tone, and lower event body temperature. This study could contribute to improving physical activity recommendations for persons with Crohn's Disease and open a new research line for an improved understanding of psychophysiological modifications of Crohn's Disease patients during exercise.

Impact of HIIT Sessions with and without Cognitive Load on Cortical Arousal, Accuracy and Perceived Exertion in Amateur Tennis Players

The aim of the present study was to investigate the effects of high-intensity interval training (HIIT) exercises, with and without cognitive load, on the accuracy, critical flicker fusion threshold (CFFT), and rating of perceived exertion (RPE) on recreational tennis players. A total of 32 players of tennis at recreational level (25 men and 7 women) were enrolled in this cross-sectional the study. Participants had to perform, randomly, two HIIT sessions. In one of them, cognitive load was induced by conducting an incongruent Stroop during rests. After training accuracy of tennis serve, CFFT, and RPE were measured. Results showed that accuracy after baseline and HIIT without cognitive load were significantly higher than after HIIT with cognitive load. RPE significantly increased (p-value < 0.001) after HIIT sessions in both, with and without cognitive load. However, significant differences were not observed between the two sessions in the RPE (p-value = 0.405). Furthermore, differences were not obtained in the CFFT neither within nor between sessions (p-value > 0.05). Therefore, HIIT with and without cognitive load increased the RPE in recreational tennis players. Furthermore, HIIT sessions with cognitive load significant altered tennis serve accuracy.

The Effect of Studying a Double Degree in the Psychophysiological Stress Response in the Bachelor's Thesis Defense

The aim of this research was to analyze the effect of studying a single or double degree in the psychophysiological stress response and academic performance of university students in their bachelor's thesis defense. We analyzed the autonomic stress response, cortical arousal, subjective distress perception, and the sense of objective and subjective academic fulfilment of 84 single-degree physiotherapy students and 26 double-degree sport sciences and physiotherapy students during their bachelor's thesis defense. The results showed that the bachelor's thesis defense was a stressful event for double-degree students, showing an activation of the sympathetic nervous system and presenting a higher autonomic habituation response for the double degree students compared to the single degree students. We found higher mean grades during the whole degree and higher grades in the written and oral bachelor's thesis academic achievements for single-degree students compared to double-degree students. No significant differences were found between single-degree and double-degree students in subjective distress perception and cortical arousal. No correlation was found between academic performance variables and subjective distress perception, cortical arousal, and autonomic modulation variables. We conclude that the bachelor's thesis defense produces a large anticipatory anxiety response in single-degree physiotherapy students and in double-degree sport sciences and physiotherapy students. Double-degree students showed higher levels of habituation and adaptability to the stressful event, with a better autonomic response. Academic achievements were significantly higher among single-degree students compared to the double-degree group.

New Training Program for the New Requirements of Combat of Tactical Athletes

Actual theaters of operations are complex contexts where soldiers must face different situations, such as symmetrical, asymmetrical, or close quarter combat. The requirements of the actual battlefield are different to the traditional conditioning military training. This new changing scenario produces an activation of the innate fight or flight defense mechanisms with large activations of the anaerobic metabolic pathways and the sympathetic autonomic nervous system. In these scenarios, the anaerobic, aerobic, and strength demands are so specific and the time to improve all training demands in the units is limited. We propose a new training periodization for the military population based on the latest research into the psychophysiological response of soldiers in actual theaters of operations (actual military missions) and actual civilian models of training and periodization to develop a specific, easy, and reliable periodization model for actual tactical athletes. This training intervention was developed in order to improve operational training according to the demands of actual theaters of operations, based on recent research in military and civilian populations. We tried to conduct a proposal that is easy to apply, with minimal use of material different to what could be found in a military base and that could be implemented in a short period of time.

Psychophysiological and Psychosocial Profile of Patients Attending Drug Addiction Centers

Drug treatment centres provide the highest level of rehab services for patients diagnosed with drug addictions. Most inpatient drug rehab programs focus on medical detox and mental health interventions. However, how to optimize the later remains a challenge. The aim of this study was to examine the psychophysiological and psychosocial profile of patients attending drug addiction centres in comparation with the general population. A total of 105 inpatient drug rehab patients and 50 participants from the general population were compared based on standardized psychophysiological and psychosocial measures. Results of this study suggest that patients attending drug addiction centers differ from general population in several different psychophysiological and psychosocial factors. Patients reported significantly lower levels of physical activity and increased sympathetic responsiveness, and significantly higher levels in loneliness, psychologically inflexibility and neuroticism. The results of this study highlight the importance of address healthy lifestyle behaviors such as sport practice and psychological variables such as loneliness, psychological (in)flexibility and neuroticism to improve current programs aim to prevent or reduce problematic drug consumptions.

Monitoring stress and allostatic load in first responders and tactical operators using heart rate variability: a systematic review

BACKGROUND

Awareness of the cumulative stress placed on first responders and tactical operators is required to manage acute fatigue, which can impair occupational performance, and may precipitate negative chronic health outcomes. The aim of this review was to investigate the utility of heart rate variability (HRV) to monitor stress and allostatic load among these populations.

METHODS

A systematic search of Academic Search Complete, MEDLINE complete, PsycINFO, SPORTDiscus and Scopus databases was conducted. Eligibility criteria: original peer reviewed research articles, written in English, published between 1985 and 2020, using human participants employed as a first responder or tactical operator, free from any psychological disorder.

RESULTS

Of the 360 articles screened, 60 met the inclusion criteria and were included for full text assessment. Articles were classified based on single or repeated stressor exposure and the time of HRV assessment (baseline, during stressor, post stressor). Singular stressful events elicited a reduction in HRV from baseline to during the event. Stressors of greater magnitude reduced HRV for extended durations post stressor. Lower resting HRV was associated with lower situational awareness and impaired decision-making performance in marksmanship and navigation tasks. There were insufficient studies to evaluate the utility of HRV to assess allostatic load in repeated stressor contexts.

CONCLUSION

A reduction in HRV occurred in response to acute physical and cognitive occupational stressors. A slower rate of recovery of HRV after the completion of acute occupational stressors appears to occur in response to stressors of greater magnitude. The association between lower HRV and lower decision-making performance poses as a useful tool but further investigations on within subject changes between these factors and their relationship is required. More research is required to investigate the suitability of HRV as a measure of allostatic load in repeated stress exposures for fatigue management in first responder and tactical operators.

Psychophysiological response of military pilots in different combat flight maneuvers in a flight simulator

OBJECTIVE

To analyze the psychophysiological response during takeoff, landing, air-air attack and air-ground attack maneuvers.

METHODS

A total of 11 expert pilots (age=33.36 (5.37)) from the Spanish Air Force participated in this cross-sectional study. Participants had to complete in a flight simulator the following missions: 1) takeoff; 2) Air-air attack; 3) Air-Ground attack, and 4) Landing. The electroencephalographic activity (EEG) and heart rate variability (HRV) were collected during all these maneuvers.

RESULTS

Significant higher values of theta (during takeoff, air-air attack and air-ground attack) EEG power spectrum were obtained when compared to baseline. Significant difference in the P3 scalp location was observed between landing and takeoff maneuvers in the beta EEG power spectrum. Furthermore, significant lower values of HRV were obtained during takeoff, landing, air-air attack and air-ground attack when compared to baseline values. Also, landing showed a higher sympathetic response when compared to takeoff maneuver.

CONCLUSION

Takeoff, landing, air-air attack or air-ground attack maneuvers performed in a flight simulator produced significant changes in the electroencephalographic activity and autonomic modulation of professional pilots. Beta EEG power spectrum modifications suggest that landing maneuvers induced more attentional resources than takeoff. In the same line, a reduced HRV during landing was obtained when compared to takeoff. These results should be considered to training purposes.

Effect of Psychophysiological Stress and Socio-Emotional Competencies on the Clinical Performance of Nursing Students during a Simulation Practice

Psychophysiological stress can affect the cognitive response and effective learning of students during medical simulation practices. This study aimed to explore the effect of psychophysiological stress and socio-emotional competencies on clinical performance during a simulation experience. A pre-test/post-test design was used to assess physiological (blood pressure, heart rate and blood oxygen saturation) and psychological parameters (stress and anxiety) as well as socio-emotional skills (cognitive load, self-efficacy and motivation) in nursing students (n = 40) before and after the simulation of a cardiopulmonary resuscitation practice. Physiological responses showed statistically significant differences between pre-test and post-test conditions for blood pressure and heart rate (p < 0.0001). Moderate and significant correlations were also observed when comparing self-efficacy with stress (r = −0.445, p = 0.004), anxiety (r = −0.467, p = 0.002) and motivation (r = −0.406, p = 0.009) measures. Similarly, cognitive-load dimensions were significantly associated with either physiological (r = −0.335, p = 0.034) or psychological (r = −0.448, p = 0.004) indicators. The analysis of multiple regression models revealed a relationship between the effectiveness of the simulated experience, post-test blood oxygen saturation, heart rate, workload and self-efficacy (R² = 0.490; F (3, 39) = 8.305; p < 0.0001; d = 1.663). Therefore, the evaluation of psychophysiological parameters and socio-emotional skills seems to provide a promising framework for predicting the quality of simulated clinical practices.

Resilience of the Hellenic navy seals assessed by heart rate variability during cognitive tasks

OBJECTIVES

The interaction between high physical performance under extreme conditions in military 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 valuable clinical tools for the assessment of cerebral and autonomic/ cardiovascular stress responses respectively.

METHODS

Thirty-four subjects were enrolled in this study. Of them, 18 were candidates under intense preparation for their enlistment in the Hellenic Navy SEALs (HN-SEALs) and 16 were healthy controls (HC). All subjects underwent stroop tasks, along with mental state and personality examination. HRV variables in time and frequency domains recordings were acquired, during each aforementioned cognitive testing procedure.

RESULTS

Our results showed that HNS's performance on both cognitive and emotion stroop tasks were equivalent to controls (p≥.054); however, HNS exhibited statistically significant lower levels of HRV in different time and frequency domain variables, compared to HC (ranged from p<.01 to p<.05). Finally, in a between group comparison of the psychometric tools, HNS had significantly higher somatization, anxiety and neuroticism than HC.

CONCLUSION

In conclusion, these findings indicate that HNS display flexibility in their autonomic regulation during cognitive and emotional tasks. This characteristic is closely related to problem solving or adaptability skills. Therefore, we support that HRV measurement turns out to be an invaluable tool for both scientific and clinical insights, promising to be an index regarding the psychophysiological resilience especially in the neurovisceral integration (NVI) model.

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 Impact of Nationality on the Psychophysiological Stress Response and Academic Fulfilment in the Final Degree Dissertation

The aims of this study were: i. to analyze the effect of nationality on the psychophysiological stress response of physiotherapy last year students in their final degree dissertations; and ii. to analyze the relationship between the stress response and academic results according to nationality. We evaluated the autonomic stress response, cortical arousal, distress subjective perception, and objective and subjective academic fulfilment in Spanish, Italian, and French physiotherapy students during their final degree dissertation. Results showed a large anticipatory anxiety response before the dissertation in the three student groups. Only the Spanish group showed an increased tendency in the habituation process, reducing the psychophysiological stress response during the dissertation, while the Italian and French groups maintained a large sympathetic activation until the end of the dissertation. Cortical arousal and subjective perception of distress were similar in the three nationalities. In addition, no correlation between academic fulfilment and autonomic modulation was found. We concluded that there was no nationality effect in the psychophysiological stress response of physiotherapy last year students in their final degree dissertation, all of them showing a large anticipatory anxiety response.

Monitorization of Autonomic Stress Response of Nurse Students in Hospital Clinical Simulation

The aims of this study were to analyze the autonomic stress response of nurse degree students during a hospital clinical simulation and to analyze differences in the autonomic stress response of nurse degree students during a hospital clinical simulation depending on their psychological profile. We analyzed in 45 nurse students their psychological profile (purpose in life, coping flexibility, perceived stress, Framingham Type A Behavior, and personality) and the autonomic modulation by the heart rate variability in a hospital clinical simulation. Students presented decreased heart rate variability and different autonomic stress responses depending on the different psychological parameters evaluated. We concluded that a hospital clinical simulation produced a large sympathetic modulation of nurse students that was maintained during the entire clinical simulation. The autonomic response was modulated by the psychological profile of students, showing higher purpose in life, perceived stress, and neuroticism, presenting higher parasympathetic modulation.

Impact of Real and Simulated Flights on Psychophysiological Response of Military Pilots

Objective: The present research aimed to analyse the autonomic, anxiety, perceived exertion, and self-confidence response during real and simulated flights. Methods: This cross-sectional study participated 12 experienced male pilots (age = 33.08 (5.21)) from the Spanish Air Force. Participants had to complete a real and a simulated flight mission randomly. The heart rate variability (HRV), anxiety, self-confidence, and rating of perceived exertion were collected before and after both manoeuvres, and HRV was also collected during both simulated and real flights. Results: When studying the acute effects of real and simulated flights, the mean heart rate, the R-to-R interval, the cognitive anxiety and the perceived exertion were significantly impacted only by real flights. Furthermore, significant differences in the mean heart rate and RR interval were found when compared to the acute effects of real and simulated flights (with higher acute effects observed in real flights). Additionally, when compared the HRV values during simulated and real flights, significant differences were observed in the RR and heart rate mean (with lower RR interval and higher heart rate mean observed during real flights). Conclusion: Real flights significantly reduced the RR interval and cognitive anxiety while increased the heart rate mean and the rating of perceived exertion, whereas simulated flights did not induce any significant change in the autonomic modulation.

Relationships Between Heart Rate Variability, Occupational Performance, and Fitness for Tactical Personnel: A Systematic Review

Objectives: Heart Rate Variability has gained substantial interest in both clinical and athletic settings as a measurement tool for quantifying autonomic nervous system activity and psychophysiological stress. However, its uses in tactical work settings, such as military, police, and firefighting environments, remain controversial. Given the physical, mental, and emotional stress public safety personnel face both operationally and in training, heart rate variability measurement may be key in promoting their health, safety and operational effectiveness.

Methods: This study identified, critically appraised, and summarized primary studies investigating relationships between heart rate variability and outcomes of interest to tactical personnel. Key literature databases were searched, and quality assessment checklists were applied to analyze retained literature. The results of the screening and assessment processes, along with key data extracted from each study were summarized and tabulated. Research gaps were also identified to facilitate improvements to how tactical personnel and health or performance providers may best utilize heart rate variability to monitor or promote personnel health and performance, and thereby facilitate public safety.

Results: Twenty studies were included and were all of generally high quality. Cohort size, length of follow-up, measurement objectives, data acquisition, and data analysis all varied considerably across studies, precluding meta-analysis. However, study results correlating heart rate variability and relevant outcomes indicated that overall, heart rate variability is an effective indicator of key fitness and performance elements in the tactical work setting.

Conclusions: Heart rate variability can be an effective health and performance tool in tactical work environments. However, measurement methods must be carefully selected and applied. Further research is required to understand causal relationships. Specifically, larger cohort inclusion and the isolation and study of specific variables unique to public safety work and training may improve the effectiveness of heart rate variability measurement to provide meaningful information to end users and providers.

Effect of Stress on Autonomic and Cardiovascular Systems in Military Population: A Systematic Review

Stress is regulated by the autonomous nervous system, increasing the sympathetic modulation when a threat is perceived. A multifactorial response usually leads to significant behavioural modifications and alterations on homeostasis and physical and psychological status. Moreover, stress is an emotional response that can lead to psychosocial and psychophysiological adversity. Regarding military population, military operations and combat exposure are important stressors that influence acute and chronic stress response in soldiers, affecting their performance and health. A bibliographic search was carried out between April and May 2019, focusing on recent studies (2013–2019) that analysed psychophysiological response, stress, stress regulation, heart rate, heart rate variability, and posttraumatic stress disorder in military population. Autonomic and cardiovascular chronic stress seems to be modulated by experience and previous specific training of each military unit. Physical exercise, music embedded with binaural beat technology, bidirectional sensory motor rhythm training, heart rate variability biofeedback, and transcutaneous vagal nerve stimulation are the main techniques applied to balance stress and to recover body homeostasis. Since military population are usually exposed to multiple stressors, knowing previous training and experience, together with developing techniques to balance stress, is the main practical application in this field of study to balance autonomic and cardiovascular systems.

Psychophysiological response in night and instrument helicopter flights

Instrument and night flights are sources of mishaps: they produce stressful contexts to aircrews in which operability can be affected. This study aimed to analyse the effect of night and instrument flights in cortical arousal, autonomic modulation, muscle strength, and stress perception. 23 people were analysed (8 helicopter pilots, 4 helicopter mechanics - Spanish Air Forces - and 11 controls) before and after instrument and night flight exposition. Lactate and perceived exertion rose after flights. Anxiety was higher in instrument than in night flights. Pilots had a higher sense of anxiety before a flight compared to mechanics, although mechanics experienced a higher raise of heart rate during flight, with lower heart rate variability. Breath capacity was affected in pilots. Cortical arousal was more affected in unexperienced than in experienced aircrew during flights. These data suggest differences in their previous training. Practitioner summary: Night and instrument helicopter flights produced a different psychophysiological response of aircrew. These results could help to design specific training for aircrew that usually face instrument and night manoeuvres. Specific training based on high-intensity interval training integrated with reverse periodisation could improve their preparation. Abbreviations: BMI: body mass index; BOS: blood oxygen saturation; BT: body temperature; CA: cognitive anxiety; CFFT: critical flicker fusion threshold; ES: effect size; FEV1: forced expiratory volume in 1 second; FVC: forced vital capacity; HF: high frequency; HR: heart rate; HRV: heart rate variability; HIS: isometric handgrip strength; LF: low frequency; NVG: night vision googles; PEF: peak expiratory flow; pNN50: proportion of differences between R-R intervals higher than 50 ms; RMSSD: square root of the mean of the sum of the squared differences between adjacent normal R-R intervals; RPE: rated of perceived exertion; SA: somatic anxiety; SC: self confidence; STAI: state trait anxiety inventory.

Psychophysiological Stress Response in an Underwater Evacuation Training

Background: This research aimed to analyze the psychophysiological stress response of air crews in an underwater evacuation training. Materials and Methods: We analyzed in 36 participants (39.06 ± 9.01 years) modifications in the rating of perceived exertion (RPE), subjective stress perception (SSP), heart rate (HR), blood oxygen saturation (BOS), cortical arousal (critical flicker fusion threshold, CFFT), heart rate variability (HRV), spirometry, isometric hand strength (IHS), and short-term memory (ST-M) before and after an underwater evacuation training. Results: The maneuver produced a significant (p ≤ 0.05) increase in the SSP, RPE, Mean HR and maximum HR (Max HR), and a decrease in minimum HR (Min HR) and HRV. Conclusion: An underwater evacuation training produced an increase in the sympathetic nervous system modulation, elevating the psychophysiological stress response of the air crews, not negatively affecting their cortical arousal.

Psychophysiological anxiety response of a rescue helicopter crew in a crane rescue manoeuvre

Background

This research aimed to analyse the psychophysiological modifications of a rescuer helicopter crew in a crane rescue manoeuvre.

Methods

We analysed in eight participants (32.5±6.6 years) divided in four categories (pilot, mechanic, rescuer and control) with variables of anxiety, rating of perceived exertion (RPE), stress subjective perception (SSP), heart rate, blood oxygen saturation (BOS), skin temperature, blood lactate, cortical arousal, autonomic modulation, legs and hands strength, legs flexibility, spirometry, urine, and short-term memory before and after a helicopter crane rescue manoeuvre.

Results

The manoeuvre produced a significant (p≤0.05) increment in the RPE, SSP, anxiety, blood lactate and sympathetic modulation, and a decrease in BOS and pulmonary capacity.

Conclusion

A helicopter rescue crane manoeuvre produced an increase in the sympathetic nervous system modulation, increasing the psychophysiological response of the crew independently of their experience or role. This information allowed us to improve actual specific operative training in this population.

Autonomic and cortical response of soldiers in different combat scenarios

INTRODUCTION

The study of chronic and acute responses when exposed to extreme, aggressive and stressful environments, such as in combat environments, is becoming increasingly popular as such information leads to better optimisation of soldiers' physical and psychological performance, as well as mission effectiveness and efficiency. Due to internal complexity, uncertainty and variability of real combat scenarios, a specific approach to all possible types of military combat scenarios is necessary.

METHODS

Modifications in the autonomic modulation and cortical arousal before and after asymmetrical, symmetrical and close quarter combat simulations were analysed in 31 male professional veteran soldiers (age: 34.5±4.2 years) with between seven and 18 years of experience in their respective units, as well as experience in international missions in current conflict areas such as Lebanon, Afghanistan, Bosnia, Kosovo and Iraq.

RESULTS

The three combat situations produced a non-significant decrease in cortical arousal after combat simulations, presenting a trivial effect size in symmetrical and close quarter combat situations and a small effect size in asymmetrical situations. HR increased significantly in the three combat situations, and close quarter combat produced the highest sympathetic modulation of the three situations analysed.

CONCLUSION

Symmetrical, asymmetrical and close quarter combat situations produced an increase in sympathetic modulation, being highest in the close quarter combat situation, where actions are performed at a close distance and in closed spaces.

Multidisciplinary intervention in the treatment of mixed anxiety and depression disorder

Depression and anxiety disorders are one of the main limiting psychopathologies in the world today. This pathology is linked to an inflammatory state and a dysregulation of both neurotransmitters and autonomic nervous system. Various treatments from psychiatric and psychological areas have shown different degrees of efficacy in their treatment, being Cognitive Behavioral Therapy one of the most successful. In addition, various interventions from other areas of knowledge are showing significant improvements in this pathology. This research aimed to analyze the psychological and physiological modifications of a multidisciplinary intervention that combines psychological treatment (Cognitive Behavioral Therapy), physical activity and nutritional intervention in a mixed anxiety and depression disorder (DSM-V). We analyzed modifications in the HAM-D depression, STAI anxiety questionnaire, subjective perceptions of anxiety, happiness, sleep and motivation and the autonomous modulation before and after a 6 multidisciplinary sessions of cognitive behavioral therapy, aerobic physical activity and nutritional intervention in a subject with a mixed anxiety and depression disorder. The results showed a reduction in the values of depression in HAM-D until the classification of non-depression, a reduction in both state and trait anxiety, an increase in the subjective perceptions of sleep, happiness and motivation and a greater parasympathetic modulation after the six intervention sessions. The combination of psychological therapy with aerobic physical activity and nutritional recommendations to treat mixed anxiety and depression disorder produced an increased parasympathetic tone and a decreased anxiety and depression symptoms in six sessions. This is a novel research that allows us to open the study of a new multidisciplinary field in the treatment of this disease that is highly present today.

Autonomic Adaption to Clinical Simulation in Psychology Students: Teaching Applications

Simulation is used to facilitate new learning in a variety of situations. One application of simulation could be to help therapists gain therapeutic skills prior to seeing clients. This particular study was interested in measuring changes in stress response by looking at subjective and objective measures of distress (as measured by SUDS, HR, and HRV) over three sessions of simulated therapy. 16 second year psychology students participated in three sessions, and had their HR and HRV measured by Polar watches. Over the three sessions, there was a decrease in perceived distress, as measured by SUDS ratings. During and between sessions, there was inconclusive change in physiological parameters.

Psychophysiological Patterns Related to Success in a Special Operation Selection Course

Actual theaters of operations require fast actions from special operations units with a high level of readiness and survival. Mission accomplishment depends on their psychological and physiological performance. The aim of the present study was to analyze: (1) the physical parameters related with success in a special operation selection course; and (2) the modifications of the psychological profile of recruits before and after a special operation selection course. Fifty-five male soldiers of the Spanish Army (25.1 ± 5.0 years, 1.8 ± 0.1 cm, 76.8 ± 7.9 kg, 24.4 ± 2.5 kg/m²) undertaking a 10-week special operation selection course performed a battery of physiological and psychological tests. Results showed how successful soldiers presented higher leg strength, anaerobic running performance, and cardiovascular response than non-successful soldiers. The psychological values of life engagement test, acceptance and action questionnaire, coping flexibility scale, and perceived stress scale did not present significant differences after the selection course. We can conclude that success in a special operation selection course was related to higher anaerobic and cardiovascular fitness. This special operation selection course did not modify the psychological profile of successful soldiers.

Psychophysiological modifications in an assault infantry manoeuvre using a chemical, biological, radiological and nuclear personal protective equipment

Introduction

The study of the psychophysiological response during combat actions has been poorly researched despite its importance for warfighter training and specific instruction. The aim of the present investigation was to analyse the effect of chemical, biological, radiological and nuclear personal protective equipment (PPE) on the psychophysiological response, mechanical and physical load and fine motor skills of professional soldiers in an endurance infantry manoeuvre.

Methods

16 soldiers conducted an assault manoeuvre with and without the PEE in separate days. We analysed before and after the manoeuvre the psychophysiological response, fine motor skills, shooting test accuracy and anxiety state.

Results

The use of PPE produced significantly higher (p<0.05) stress, fatigue, temperature, HR, somatic anxiety and time in middle and high HR zones and significantly lower values in speed average and maximum speed. These findings can be used to improve the training and specific instruction for professionals who require the use of PPE equipment.

Conclusion

The use of the PPE suit in an assault manoeuvre produces a decrease in the speed of movement, an increase in HR, body temperature, somatic anxiety and subjective perception of effort.

Effect of different combat jet manoeuvres in the psychophysiological response of professional pilots

Extreme limits of the human body could be reached in air combat. We analysed 29 fighter pilots before and after offensive and defensive manoeuvres on heart rate (HR), heart rate variability, leg and hand strength, spirometry, temperature, blood oxygen saturation (BOS), lactate, hydration (USG), cortical activation, memory and psychological variables. The defensive manoeuvre produced a significative decrease in forced vital capacity from spirometry and USG post flight, a moderate effect in the decrease in cognitive anxiety and an increase in leg strength. A significant increase in mean HR and an increase with a large effect size was reported for Stress Subjective Perception and Rating of Perceived Exertion in both manoeuvres. With this data we can conclude that high level of physical fitness and specific training programs should be applied to fighter pilots.

Influence of psychological profile in autonomic response of nursing students in their first hospital clinical stays

BACKGROUND

This research aimed to analyse the psychological profile of nursing students and its relationship with the physiological anticipatory anxiety response at the earliest clinical practices; and to analyse the habituation response at the psychophysiological level of nursing students throughout their first clinical practices.

METHODS

18 students of the first year of Nursing degree were studied in their first clinical stays. Their psychophysiological stress response was evaluated throughout the analysis of the autonomic modulation and their subjective perception to stress at the beginning and at the end of the stays. In addition, an inventory of psychological test was carried out to observe its association with the psychophysiological stress response.

RESULTS

The results showed that the students presented a large anticipatory anxiety response at the beginning of the stays, as well as an absence of a habituation process during the stay. It was also observed a positive relation between the loneliness perceived and the autonomic stress response.

CONCLUSION

The clinical stays in the hospital performed by first year students of the nursing degree, did not produce the expected habituation response at psychophysiological level. Also, a higher perception of social isolation was significantly related with a higher objective (sympathetic modulation) and subjective (perceived stress) stress responses.

Analysis of Psychophysiological Stress Response in Higher Education Students Undergoing Clinical Practice Evaluation

The aim of this study was to analyze the psychophysiological response of Physiotherapy degree students during a complete clinical practice as well as their psychological profile in relation to coping style in stressful situations, and its impact on academic performance. We analysed in 15 students heart rate variability (HRV) to analyse autonomic modulation in three moments during the entire clinical practices of 3 months (4 h per day, 3 days per week), first session, middle session and last session; perceived stress, personality, life engagement, cognitive flexibility before starting the clinical practice the academic performance after the clinical practice. Results based on HRV and related indexes parameters fail to indicate the expected autonomic adaptation during the practice. A complete clinical practice of Physiotherapy degree students did not produce an habituation process since a high sympathetic autonomic nervous system modulation was measured in the beginning, at the middle and at the final of the clinical practice. Below-average scores are presented in a personality factor associated with traditional and non-adaptive coping styles that could explain the non-habituation of the students. Finally, none of the analyzed indexes has been able to relate to academic performance.

Evaluation of Central Fatigue by the Critical Flicker Fusion Threshold in Cyclists

Central fatigue related in sport stimuli was studied by Critical Flicker Fusion Threshold (CFFT) to know the influence of exercise on the central nervous system (CNS), but there is a lack of knowledge about the central or peripheral fatigue in endurance events. This study aimed to analyze changes in CFFT before and after the incremental cycle ergometer test as a means to assess the fatigue of the CNS. CFFT ascending and descending, the subjective criterion and sensory sensitivity were analysed in 8 professional male cyclists (72.1 ± 5.59 kg, 180.3 ± 6.43 cm, 17.4 ± 0.7 years) before and after a maximum incremental cycle ergometer test (start 50w increases 50w each 5 min). In this incremental test, the induced fatigue was probably more a peripheral phenomenon than one due to central nervous system fatigue, because sensory sensitivity did not significantly decrease. In conclusion, an incremental cycle ergometer test increased the cortical arousal and does not affect negatively the CNS of professional cyclists.

Psychophysiological response of different aircrew in normobaric hypoxia training

Hypoxia remains the most important hazard in high altitude flights, but there is still a need for deeper analysis of the effect of hypoxia exposition in the psychophysiological and cognitive functions. The aim of this study was to study the effect of hypoxia training in cortical arousal, autonomic modulation, muscle strength and cognitive function. We analysed 23 male aircrew personnel of the Spanish Army and Air Force (10 Helicopter Pilots, 7 Transport Aircrew, 3 Transport Pilots and 3 F-18 Fighter Pilots) before, during and after a normobaric hypoxia exposition. Hypoxia produced an increase in perceived stress and effort, a higher Heart Rate and a decreased function of breath muscles. Working memory and pattern recognition were impaired after hypoxia exposition. Significant differences were found in cognitive tests performance among aircrew groups, suggesting differences on their previous training. These results can improve specific training for better preparation of pilots and aircrews for hypoxic threats. Practitioner summary: Distinct aircrew preparation produces a different hypoxia exposition effect on psychophysiological response and cognitive functions. Hypoxia produced an increase in Heart Rate, a decreased function of breath muscles, being more negatively affected in Transport Pilots. Cognition abilities were impaired after hypoxia exposition, independently of the aircrew group.

Psychophysiological Monitorization in a Special Operation Selection Course

The present research aimed: i. to analyse the psychophysiological response of soldiers undertaking a special operation selection course; ii. to study the relationship between fat and muscle loss and the psychophysiological response of soldiers undertaking a special operation selection course. We analysed 46 professional soldiers from a special operations unit (25.1 ± 5.0 years, 1.8 ± 0.1 cm, 76.8 ± 7.9 kg, 24.4 ± 2.5 kg/m²) undertaking the last phase of their 10 weeks special operation selection course. Before and immediately after the exercise the following variables were assessed: Stress subjective perception, fatigue subjective perception, rating of perceived perception, cortical arousal, body temperature, blood oxygen saturation, spirometry, isometric hand strength, lower body muscular strength, urine, body composition, life engagement test, coping flexibility scale, acceptance and action questionnaire, perceived stress scale, anxiety state, visual analogue scale and differential aptitude test. A special operation selection course induced an intense stress and physical response as suggested by the psychophysiological changes with a significant (p < 0.05) increase in fatigue and stress subjective perception, blood oxygen saturation, Ph, cognitive impairment and motivation-loss. Moreover, decreased leg strength, peak expiratory flow, cortical arousal, body composition, body weight, fat and muscle mass, anxiety stress, alertness, sadness and tension decreased after the exercise. Regarding body composition, higher muscle mass loss participants were related to a higher cognitive impairment and similar psychophysiological response than lower fat mass loss participants.

Higher use of techniques studied and performance in melee combat produce a higher psychophysiological stress response

We aimed to analyse the effectiveness of an operative training in soldiers' psychophysiological and melee combat performance. Nineteen soldiers performed a 50-hr training for 10 weeks. After training, they were divided into two groups: higher performance group (HPG) and lower performance group (LPG), then they conducted a realistic melee simulation where psychophysiological response, task performance, and the utilization of techniques learned were measured. HPG presented a significantly (p < 0.05) higher heart rate, blood lactate, and jump height; a lower blood oxygen saturation, task performance mark, use of studied techniques than LPG after the simulation; and a higher low frequency/high frequency ratio of heart rate variability previous the simulation than LPG. Independent of performance and the use of studied techniques by the participants, the melee simulation produced an increase in fight or flight response, increasing rated of stress and perceived exertion, sympathetic modulation, and physiological response. A specific melee combat training program induced different modifications in psychophysiological and task performance depending on the level of studied technique used. HPG presented a significantly higher cardiovascular response than LPG and time perception, and memory presented no differences between groups; also HPG presented a significantly higher use of studied techniques.

Psychophysiological response of air mobile protection teams in an air accident manoeuvre

Different extreme contexts elicit a stress response on human body, specifically on combat produces an increase of sympathetic nervous system and a direct effect on the organic response. This research aimed to study the psychophysiological response of an air security force in a simulated air accident in a hostile area and its subsequent subterfuge to a safe area. We analyzed 13 soldiers (32.4 ± 8.0 years) from an air security force unit of the Spanish Air Force who were divided into three teams to conduct the manoeuvre. We analyzed before and after the manoeuvre psychological well-being scale, personal views survey, recovery-stress questionnaire (REST-52 Sport); heart rate variability, visual analogue scale, rated of perceived exertion, spirometry, hydration and hand strength were analyzed during the four days of the manoeuvre: This produced a significantly (p < .05) increase in sympathetic modulation, hand strength, dehydration status, general and specific stress from RESTQ-52. With this data we can conclude that an air accident manoeuvre of three nights and four days causes in the air mobile protection team a high sympathetic nervous system modulation, increases on muscle strength manifestations and stress and a dehydration status.

Nutrition, hydration and ergogenic aids strategies in ultraendurance mountain events

BACKGROUND

The purpose of the present research was to analyze nutrition, hydration and ergogenic aids strategies in ultraendurance mountain events.

METHODS

A total of 386 ultraendurance mountain races finishers were analyzed. They were divided into three groups according to their race distance: G1, distance less than 45 km (N.=250); G2, distances between 45 and 90 km (N.=71); G3, distances longer than 90 km (N.=65). The ergogenic, nutritional and hydration strategies were quantified after each race by a questionnaire.

RESULTS

We found a higher ingestion of (0.56±0.95), caffeine (G3 203.8±211.5 mg), water (G3 7.1±3.7 l) and portion of sandwich (nutrition 5.3±7.4) nonsteroidal anti-inflammatory drug (NSAID) in longer distance probes. Higher performance runners in low and medium distances consumed a significantly (P>0.05) lower quantity of gels (higher 0.76±0.98 vs. lower 1.38±1.38), and muesli bar (higher 1.09±1.13 vs. lower 2.04±1.94), and in long distances higher performance consumed more water (M±SD; higher 8.23±3.92 vs. lower 6.12±3.28) than lower performance ones. They also could maintain a higher rated of perceived exertion than lower performance (G3 M±SD; higher 16.7±2.28 vs. lower 18.2±1.71).

CONCLUSIONS

Higher distance presented higher nutritional, caffeine and NSAIDs ingestion than lower distances, also, higher performance athletes of higher distance presenter higher water and nutritional ingestion than lower performance ones. In lower distance probes, higher performance athletes presented lower hydration and nutritional ingestion than lower performance athletes.

State of the Art on the Use of Portable Digital Devices to Assess Stress in Humans

The aim of this study is to review the current tools for the assessment of stress response in humans, ranging from the use of psychological questionnaires to the latest tools involving portable digital devices. Practical implications in educational context are further discussed.

Effect of experience, equipment and fire actions in psychophysiological response and memory of soldiers in actual underground operations

The present study aimed to analyze the effect of underground operations on the psychophysiological and memory response of soldiers taking into consideration experience, the use of nocturne vision systems and previous combat actions on the psychophysiological response. Seventy participants were recruited and divided in four groups, three experimental groups with different experimental conditions, SNFV (Soldiers No-Fire Night-Vision), SFV (Soldiers Fire Night-Vision), SNFNV (Soldiers No-Fire No Night-Vision), and one control group, CNFV (Control No-Fire Night-Vision). We analyzed modifications in psychophysiological and memory response pre and post an underground operation. The underground operation produced a significant increase (p < 0.05) in blood lactate, blood oxygen saturation, rated perceived exertion, heart rate, cognitive and somatic anxiety and sympathetic modulation in all groups. Groups with higher stress values scored higher incorrect items in the memory post mission questionnaire. The higher psychophysiological activation correlated positively with cognitive impairment and lower memory. We concluded that an underground operation produced an increase in psychophysiological activation and a negative effect on memory, being modulated by previous training and experience. The lack of special equipment as night vision systems in underground operations induced similar stress response than prior combat actions, decreasing conciseness of time.

Use of Psychophysiological Portable Devices to Analyse Stress Response in Different Experienced Soldiers

Previous studies have shown that actuate stress have a negative effect on working memory, visio-spatial ability and symptoms of disassociation. We conducted the present research with the aim of to analyse the effect of experience and training in psychophysiological response, attention and memory of soldiers in combat. Variables of blood lactate, blood glucose, blood oxygen saturation, body temperature, heart rate, lower body muscular strength manifestation, autonomic modulation, cortical arousal, cognitive and somatic anxiety, and memory by a post mission questionnaire were analysed before and after a combat simulation in 49 soldiers of Spanish Army. Combat simulation produced a significant increase (p < 0.05) in blood lactate, blood glucose, blood oxygen saturation, rated perceived exertion, heart rate, cognitive and somatic anxiety. Significant increase in low frequency domain and significant decrease in high frequency domain of the heart rate variability was found in experienced and highly trained soldiers. The percentage of correct response in the post mission questionnaire indicated that elements better remembered were those related with soldier integrity and considered as a possible life threat, Significant differences in the post mission questionnaire by experience and training was also found. Correlation analysis showed that higher psychophysiological activation correlated positively with cognitive impairment and lower memory. As a conclusion, higher experienced soldiers presented higher physiological activation as well as cognitive and memory impairment than lower experienced soldier after a combat simulation and memory function was modulated by the stimulus nature.