Autonomic and cortical response of soldiers in different combat scenarios

Optimising Combat Readiness: Practical Strategies for Integrating Physiological and Psychological Resilience in Soldier Training

This narrative review examines the intricate psychophysiological interplay between cognitive functions and physical responses within military personnel engaged in combat. It elucidates the spectrum of responses elicited by symmetric and asymmetric warfare alongside specialised combat scenarios, including close-quarters and subterranean warfare. Central to this discourse is the emphasis on integrating training programs beyond physical conditioning to encompass psychological resilience and decision-making efficacy under duress. The exploration further ventures into applying advanced technologies such as virtual reality and wearable devices, highlighting their pivotal role in augmenting training outcomes and supporting soldier health. Through a detailed analysis of psychophysiological variations across different military branches of service, the narrative review advocates for bespoke training regimens and support frameworks tailored to address the unique exigencies of each service branch. Concluding observations stress the importance of evolving military training paradigms, advocating for adopting realistic, immersive training simulations that mirror the complexities of the contemporary battlefield. This synthesis aims to contribute to the ongoing discourse on optimising military training protocols and enhancing the operational readiness and well-being of armed forces personnel. This narrative review is essential for military psychologists, trainers, and policymakers, aiming to bridge the gap between theoretical knowledge and practical implementation in military training programs.

Physical fitness and anthropometrics in Finnish soldiers during their early career: prospective changes during a 3-year follow-up

INTRODUCTION

Physical fitness is a fundamental capability required of military personnel, but studies focusing on longitudinal changes in physical fitness and anthropometrics in soldiers are lacking. The aim was to evaluate physical fitness and anthropometrics in soldiers during their early career.

METHODS

A 3-year prospective study included 180 male soldiers (baseline age 26±2 years) with measures of a 12 min running test, standing long jump, sit-up and push-up tests, and body mass, height and waist circumference (WC). Baseline data were stratified into tertiles, and the changes within each tertile were analysed using dependent t-tests and analysis of variance.

RESULTS

12 min running test distance decreased on average by 2% (-54 m), sit-up performance 3% (-1.5 repetitions (reps)/min), push-up performance 4% (-1.9 reps/min) and standing long jump performance 1% (-2.1 cm) over the 3-year period (p<0.05). Both aerobic and muscular fitness decreased consistently among the highest baseline tertile (12 min running test: -70 m, sit-ups: -3.2 reps/min, push-ups: -7.5 reps/min, standing long jump: -5.5 cm; p<0.001), whereas both aerobic and muscular fitness levels were maintained and push-up performance was improved (p<0.05) in the lowest baseline tertiles. Body mass increased on average by 4% (+3.4 kg) and WC by 4% (+3.9 cm) (p<0.001), and these increases were observed for all baseline tertiles (p<0.05).

CONCLUSIONS

Small decrements in physical fitness and anthropometrics exist during the early career of soldiers. The changes in physical fitness differed according to baseline fitness levels. The results indicate that support for exercise training may be needed even in a soldier's early career.

Influence of Two Exercise Programs on Heart Rate Variability, Body Temperature, Central Nervous System Fatigue, and Cortical Arousal after a Heart Attack

Cardiovascular diseases (CVD) are the leading cause of death globally. Cardiac rehabilitation (CR) programs' benefits are overall consensual; however, during exercise, progressive physiological effects have not been studied yet in cardiac patients. Our study aims to analyze physiological parameters of thermography, heart rate variability (HRV), blood pressure, central nervous system (CNS) fatigue, and cortical arousal in heart attack patients (HAP) who belong to CR programs of High-Intensity Interval Training (HIIT) and Moderate-intensity Continuous Training (MICT) compared to healthy participants. In this case control study, two HAP patients (both male, age 35 and 48, respectively) and two healthy people (both male, age 38 and 46, respectively) were randomly assigned in a 1:1:1:1 allocation ratio to one of four groups: cardiac MICT, cardiac HIIT, control MICT, and control HIIT. The HIIT at ≈85-95% of peak heart rate (HR) was followed by a one-minute recovery interval at 40% peakHR, and MICT at ≈70-75% of peakHR. Outcome measurements included thermography, HRV, blood pressure, CNS fatigue, and cortical arousal; The HAP presents more than twice the CNS fatigue in MICT than control participants, but HIIT has almost the same CNS fatigue in HAP and control. In addition, both of the HAP groups presented higher temperatures in the chest. The HIIT protocol showed better physiological responses during exercise, compared to MICT in HAP.

The Effect of Expertise during Simulated Flight Emergencies on the Autonomic Response and Operative Performance in Military Pilots

Heart rate variability (HRV) and performance response during emergency flight maneuvers were analyzed. Two expert pilots (ages 35 and 33) and two rookie pilots (ages 25) from the Portuguese Air Force participated in this case-control report study. Participants had to complete the following emergency protocols in a flight simulator: (1) take-off engine failure, (2) flight engine failure close to the base, (3) flight engine failure far away from the base, and (4) alternator failure. The HRV was collected during all these maneuvers, as well as the performance data (the time it took to go through the emergency protocol and the subjective information from the flight simulator operator). Results regarding autonomic modulation showed a higher sympathetic response during the emergency maneuvers when compared to baseline. In some cases, there was also a higher sympathetic response during the emergency maneuvers when compared with the take-off protocol. Regarding performance data, the expert pilots accomplished the missions in less time than the rookie pilots. Autonomic modulation measured from HRV through portable devices can easily relay important information. This information is relevant since characterizing these maneuvers can provide helpful information to design training strategies to improve those psychophysiological responses.

Validity of Detrended Fluctuation Analysis of Heart Rate Variability to determine intensity thresholds in professional cyclists

BACKGROUND

The evaluation of performance in endurance athletes and the subsequent individualization of training is based on the determination of individual physiological thresholds during incremental tests. Gas exchange or blood lactate analysis are usually implemented for this purpose, but these methodologies are expensive and invasive. The short-term scaling exponent alpha 1 of detrended Fluctuation Analysis (DFA-α1) of the Heart Rate Variability (HRV) has been proposed as a non-invasive methodology to detect intensity thresholds.

PURPOSE

The aim of this study is to analyse the validity of DFA-α1 HRV analysis to determine the individual training thresholds in elite cyclists and to compare them against the lactate thresholds.

METHODOLOGY

38 male elite cyclists performed a graded exercise test to determine their individual thresholds. HRV and blood lactate were monitored during the test. The first (LT1 and DFA-α1-0.75, for lactate and HRV, respectively) and second (LT2 and DFA-α1-0.5, for lactate and HRV, respectively) training intensity thresholds were calculated. Then, these points were matched to their respective power output (PO) and heart rate (HR).

RESULTS

There were no significant differences (p > 0.05) between the DFA-α1-0.75 and LT1 with significant positive correlations in PO (r = 0.85) and HR (r = 0.66). The DFA-α1-0.5 was different against LT2 in PO (p = 0.04) and HR (p = 0.02), but it showed significant positive correlation in PO (r = 0.93) and HR (r = 0.71).

CONCLUSIONS

The DFA1-a-0.75 can be used to estimate LT1 non-invasively in elite cyclists. Further research should explore the validity of DFA-α1-0.5.

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.

Factors Influencing Preparedness for Bioterrorism among Koreans

Bioterrorism is destructive enough to cause a societal collapse, and preparation for bioterrorism is imperative. This study aims to identify the factors influencing preparedness for bioterrorism among Koreans. A total of 1050 subjects were included in the study, which were allocated according to region and age in proportion to population. An online survey was used to examine the following factors: participants' general characteristics; cognitive factors including perceived probability, perceived seriousness, perceived personal impact, perceived coping efficacy, and perceived resilience; social-contextual factors including perceived governmental preparedness and perceived front-line preparedness; affective responses including affective response to terrorism and anxiety; and bioterrorism preparedness. The factors influencing the level of preparedness for bioterrorism included age, marital status, experience of bioterrorism education, perceived personal impact, perceived coping efficacy, perceived resilience, and perceived front-line preparedness. The factors that most significantly affected the level of preparedness for bioterrorism were perceived coping efficacy and perceived front-line preparedness, with an R2 of 41.4%. Relevant education and public relations programs should be strengthened to help citizens minimize their exposure and known to inform relevant institutions in the event of suspected bioterrorism, and front-line responders should cultivate their ability to respond to bioterrorism quickly and accurately.

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.

Psychophysiological respond in a swimming ultra-endurance event

BACKGROUND

Ultra-endurance events under critical environmental conditions represent unique stress, resulting in acute marked adaptations to the cardiovascular, respiratory, metabolic and neuromuscular systems of the organism. In line with this, no studies in swimming events were found thus far.

METHODS

This research aimed to analyze the psychophysiological response of swimmers in an ultra-endurance swimming event. Changes in the rate of perceived exertion, blood lactate concentration, 1000m swimming time and cortical arousal were measured in 19 male volunteer swimmers (28.0±5.6 years; 175.0±7.9 cm; 70.1±7.8 kg) in 3 moments during a 24h swimming event.

RESULTS

We found a significant increase in lactate concentration after series 1, decreasing the values in series 2 and series 3. Cortical arousal decreased significantly in series 3 respect the basal sample. Rate of perceived exertion significantly increased in the swimming ultra-endurance event and 1000m swimming time was maintained during the series analyzed.

CONCLUSIONS

An ultra-endurance swimming event produced an increase in blood lactate concentration and rated of perceived exertion and a decrease in cortical arousal, not affecting average swimming velocity along the event.

Could academic experience modulate psychophysiological stress response of biomedical sciences students in laboratory?

The aim of the present research was to analyse the subjective and objective psychophysiological stress response of experienced and non-experienced Pharmacy and Biotechnology students in laboratory practices. We analysed in 82 Pharmacy and Biotechnology degree students divided into two groups (non-experienced: n: 53; experienced: n: 29) the autonomic stress response by the analysis of heart rate variability (HRV) before, during and after and distress perception before and after a laboratory practice. Results showed how students in both groups presented a large anticipatory anxiety response at the beginning of the practise (low HRV values). During the entire laboratory practice, non-experienced students showed a maintained sympathetic modulation while experienced students presented a higher parasympathetic modulation (high HRV values) consistent with a habituation process. Laboratory practise performed by Pharmacy and Biotechnology students produced an anticipatory anxiety response independently of their experience, but, non-experienced students showed a lower habituation response in both subjective and objective stress records than experienced students at the end of the laboratory practice.