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FL vs. SC comparisons for: A) cortisol; B) DHEAS; and C) DHEAS-Cortisol ratio. All values are mean 6 SD. P-values are provided for post hoc comparisons across conditions at each time point: * P , 0.01; ** P , 0.001.
Source publication
We examined the responsiveness of both cortisol and dehydroepiandrosterone sulfate (DHEAS) to the stress of survival training in military men and evaluated relationships to performance, peritraumatic dissociation, and the subsequent impact of stressful events.
Baseline salivary cortisol samples were self-collected by 19 men at 0900 and 1930 in a fr...
Contexts in source publication
Context 1
... repeated-measures ANOVA yielded a signifi cant inter- action (F [1,18] 5 42.9, P , 0.001, observed power 5 1.0), such that cortisol concentrations were higher in the morning than in the evening during FL (indicative of the normal diurnal pattern), but increased substantially from morning to evening during SC. Mean cortisol val- ues increased signifi cantly in response to SC at both time points [0900: t 5 4.1, P , 0.001, mean percent D 5 1 113% (SD 5 120); 1930: t 5 10.2, P , 0.001, mean percent D 5 1 1388% (SD 5 1335)] ( Fig. 1A ). ...
Context 2
... FL were 1.7 ng z ml 2 1 (SD 5 1.3) at 0900 and 1.5 ng z ml 2 1 (SD 5 0.8) at 1930; during SC, DHEAS values were 6.7 ng z ml 2 1 (SD 5 3.5) at 0900 and 4.5 ng z ml 2 1 (SD 5 3.0) at 1930. A repeated-measures ANOVA revealed a signifi cant overall effect of SC on DHEAS concentrations [F(1,11) 5 18.3, P , 0.001; ob- served power 5 0.97]. As shown in Fig. 1B , mean DHEAS values increased signifi cantly in response to SC at both time points [0900: t 5 5.4, P , 0.001, mean percent D 5 1 381% (SD 5 284); 1930: t 5 4.1, P , 0.01, mean per- cent D 5 1 207% (SD 5 138)]. DHEAS values were sig- nifi cantly higher in the morning compared with evening hours during SC, but this downward shift was not ...
Context 3
... signifi cant interaction was observed [F(1,11) 5 18.1, P , 0.001, observed power 5 0.97]. Mean DHEAS-cortisol ratios increased signifi cantly from FL to SC at 0900 [t 5 2 3.0, P , 0.01, mean percent D 5 1 130 (SD 5 159)]; conversely, DHEAS-cortisol ratio scores decreased signi fi cantly from FL to SC at 1930 [t 5 3.2, P , 0.01, mean percent D 5 2 69 (SD 5 20)] ( Fig. 1C ). ...
Context 4
... inverse relationships were also observed be- tween OP-High and percent change (FL to SC) in DHEAS (r 5 2 0.65, P , 0.05) and DHEAS-cortisol ratio (r 5 2 0.61, P , 0.05) measured at the 1930 time point ( N 5 12). An objectively measured score of resilience during the same challenge was positively associated with corti- sol concentrations (r 5 0.56, P , 0.01) and inversely re- lated to DHEAS-cortisol ratios at 0900 during SC (r 5 2 0.70, P , 0.01) ( N 5 12). Overall performance during a low-intensity, captivity-related challenge (OP-Low) was positively associated with DHEAS during SC at the 0900 time point (r 5 0.59, P , 0.05) and a signifi cant trend emerged between OP-Low and the DHEAS-cortisol ratio at the same time point (r 5 0.55, P 5 0.06) ( N 5 12). ...
Context 5
... objectively measured score of resilience during the same challenge was positively associated with corti- sol concentrations (r 5 0.56, P , 0.01) and inversely re- lated to DHEAS-cortisol ratios at 0900 during SC (r 5 2 0.70, P , 0.01) ( N 5 12). Overall performance during a low-intensity, captivity-related challenge (OP-Low) was positively associated with DHEAS during SC at the 0900 time point (r 5 0.59, P , 0.05) and a signifi cant trend emerged between OP-Low and the DHEAS-cortisol ratio at the same time point (r 5 0.55, P 5 0.06) ( N 5 12). ...
Citations
... Associations between HRV and cortisol and DHEA-S (and their ratio to each other) have also been highlighted as promising approaches in the understanding of stress responses and changes in cognitive the performance within military operators. Hansen et al., 2003;Haufler et al., 2018;Johnsen et al., 2012;Martin, McLeod et al., 2019;Morgan III et al., 2004Rensberger, 2018;Taylor et al., 2007). Data from the current investigation supports this notion, with a considerable decrease in RMSSD, (31, 36 and 41%) compared with baseline values after each Light grey, white, and dark grey areas denote the 5.1 kmÁh À1 , 6.5 kmÁh À1 , and simulated fire and manoeuvre portions of the protocol, respectively. ...
Background
Dismounted military operations require soldiers to complete cognitive tasks whilst undertaking demanding and repeated physical taskings.
Objective
To assess the effects of repeated fast load carriage bouts on cognitive performance, perceptual responses, and psychophysiological markers.
Methods
Twelve civilian males (age, 28 ± 8 y; stature, 186 ± 6 cm; body mass 84.3 ± 11.1 kg; V̇O 2max , 51.5 ± 6.4 mL·kg ⁻¹ ·min ⁻¹ ) completed three ∼65-min bouts of a Fast Load Carriage Protocol (FLCP), each interspersed with a 65-min recovery period, carrying a representative combat load of 25 kg. During each FLCP, cognitive function was assessed using a Shoot/Don’t-Shoot Task (SDST) and a Military-Specific Auditory N-Back Task (MSANT), along with subjective ratings. Additional psychophysiological markers (heart rate variability, salivary cortisol, and dehydroepiandrosterone-sulfate concentrations) were also measured.
Results
A main effect of bout on MSANT combined score metric ( p < .001, Kendall’s W = 69.084) and for time on the accuracy-speed trade-off parameter of the SDST ( p = .025, Ѡ ² = .024) was evident. These likely changes in cognitive performance were coupled with subjective data indicating that participants perceived that they increased their mental effort to maintain cognitive performance (bout: p < .001, Ѡ ² = .045; time: p < .001, Ѡ ² = .232). Changes in HRV and salivary markers were also evident, likely tracking increased stress.
Conclusion
Despite the increase in physiological and psychological stress, cognitive performance was largely maintained; purportedly a result of increased mental effort.
Application
Given the likely increase in dual-task interference in the field environment compared with the laboratory, military commanders should seek approaches to manage cognitive load where possible, to maintain soldier performance.
... Employment of these types of studies, along with monitoring of operationally relevant measures, may help advance the development of treatment for stress-related diseases and disorders specific to this population in the long-term [15]. In the short-term, stress monitoring may help identify acute decreases in key performance indicators allowing individuals to better prepare for the environments they may find themselves in [16]. ...
... Additionally, in firefighters, multiple live-fire training scenarios were investigated both with and without personal protective equipment (PPE) and self-contained breathing apparatus (SCBA) masks [29,30,34,36,42,43,[55][56][57]. Military personnel were examined during combat simulations [24,26,46,47,49,50,62,63], cargo flights and parachute jumps [21,25,31,45], underwater evacuation training [54], selection courses [27,28,35,39], and longer term (5+ days in length) military field training [15,16,23,38,40,41,[51][52][53]64]. Every operational task and training environment reported resulted in an increased level of stress, observed through both objective and subjective measures. ...
... These include cortisol, testosterone, IGF-1, SHBG, DHEA, IL-6, NPY, STfR, hepcidin, TNF-alpha, BDNF, epinephrine, norepinephrine, dopamine, C-reactive protein, TSH, leptin, T3 and T4. Significant increases were observed in serum cortisol [15,27,39,41,52,53,64], SHBG [27,41,51,52], epinephrine [15,64], norepinephrine [15,64], dopamine [64], DHEA [16,53], sTfR [15], IL-6 [38], C-reactive protein [27] and hepcidin [38] during operational tasks, all indicating in increase in stress. Furthermore, significant decreases were observed in serum testosterone [15,27,39,41,52,53,64], IGF-1 [39][40][41]52], TNF-alpha [40], leptin [40], T3 and T4 [27]. ...
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.
... Associations between HRV and cortisol and DHEA-S (and their ratio to each other) have also been highlighted as promising approaches in the understanding of stress responses and changes in cognitive the performance within military operators. Hansen et al., 2003;Haufler et al., 2018;Johnsen et al., 2012;Martin, McLeod et al., 2019;Morgan III et al., 2004Rensberger, 2018;Taylor et al., 2007). Data from the current investigation supports this notion, with a considerable decrease in RMSSD, (31, 36 and 41%) compared with baseline values after each Light grey, white, and dark grey areas denote the 5.1 kmÁh À1 , 6.5 kmÁh À1 , and simulated fire and manoeuvre portions of the protocol, respectively. ...
Background: Dismounted military operations require soldiers to simultaneously complete cognitive tasks whilst undertaking demanding and repeated physical taskings.Objective: To assess the effects of repeated fast load carriage bouts on cognitive performance, perceptual responses, and psychophysiological markers.Methods: Twelve civilian males (age, 28 ± 8 y; stature, 186 ± 6 cm; body mass 84.3 ± 11.1 kg; V̇O2max, 51.5 ± 6.4 mL·kg-1·min-1) completed three ~65-minute bouts of a Fast Load Carriage Protocol (FLCP), each interspersed with a 65-minute recovery period, carrying a representative combat load of 25 kg. During each FLCP, cognitive function was assessed using a Shoot-/Don’t-Shoot Task (SDST) and a Military-Specific Auditory N-Back Task (MSANT), along with subjective ratings. Additional psychophysiological markers (heart rate variability, salivary cortisol, and dehydroepiandrosterone-sulfate concentrations) were also measured.Results: A main effect of bout on MSANT combined score metric (p<0.001, Kendall’s W=69.084) and for time on the accuracy-speed trade-off parameter of the SDST (p=0.025, Ѡ2=0.024) was evident. These likely changes in cognitive performance were coupled with subjective data indicating that participants perceived that they increased their mental effort to maintain cognitive performance (bout: p<0.001, Ѡ2=0.045; time: p<0.001, Ѡ2=0.232). Changes in HRV and salivary markers were also evident, tracking increased physical exertion. Conclusion: Despite the increase in physiological and psychological stress, cognitive performance was largely maintained; purportedly a result of increased mental effort.Application: Given the likely differences in dual-task interferences between laboratory and field-based investigations, military commanders should seek approaches to manage cognitive load where possible, to maintain soldier performance.
... Five studies measured biological markers of psychological resilience during captivity-type tasks. Markers included saliva cortisol and DHEA-S [68]. Overall performance during the high-intensity challenge was inversely related to the cortisol-DHEA-S ratio, whereas, performance during the low-intensity challenge was related to DHEA-S measured during the captivity phase. ...
A narrative systematic literature review was conducted to explore resilient performance in defence and security settings. A search strategy was employed across a total of five databases, searching published articles from 2001 onwards that assessed performance and optimal function in relation to resilience, in defence and security personnel. Following narrative synthesis, studies were assessed for quality. Thirty-two articles met inclusion criteria across a range of performance domains, including, but not limited to, course selection, marksmanship, land navigation, and simulated captivity. Some of the key findings included measures of mental toughness, confidence, and a stress-is-enhancing mindset being positively associated with performance outcomes. There was mixed evidence for the predictive value of biomarkers, although there was some support for cortisol, dehydroepiandrosterone sulfate (DHEA-S) and neuropeptide-y (NPY), and vagal reactivity. Interventions to improve resilient performance were focused on mindfulness or general psychological skills, with effects generally clearer on cognitive tasks rather than direct performance outcomes in the field. In sum, no single measure, nor intervention was consistently associated with performance over a range of domains. To inform future work, findings from the present review have been used to develop a framework of resilient performance, with the aim to promote theoretically informed work.
... Data suggests that changes in CORT and OCN are related to change in extremity temperature and that baseline values of these analytes may be indicative of thermoregulatory capacity in the extremities. There is ample data on acute stress response in military personnel undergoing rigorous physical training and mental/ psychological stress (Morgan et al., 2000b;Taylor, et al., 2007b;Castellani et al., 2017;Taylor et al., 2021). Different types of stressors led to varying effects on neuroendocrine responses; however, collectively, stress from interrogation, skydiving, and intense physical training resulted in elevated cortisol and DHEA and depressed testosterone (Morgan, et al., 2000a;Morgan et al., 2001;Morgan et al., 2004;Taylor MK. et al., 2007;Taylor, et al., 2007b;Morgan et al., 2009). ...
... There is ample data on acute stress response in military personnel undergoing rigorous physical training and mental/ psychological stress (Morgan et al., 2000b;Taylor, et al., 2007b;Castellani et al., 2017;Taylor et al., 2021). Different types of stressors led to varying effects on neuroendocrine responses; however, collectively, stress from interrogation, skydiving, and intense physical training resulted in elevated cortisol and DHEA and depressed testosterone (Morgan, et al., 2000a;Morgan et al., 2001;Morgan et al., 2004;Taylor MK. et al., 2007;Taylor, et al., 2007b;Morgan et al., 2009). Yet, to our knowledge there is no data on stress response to prolonged cold water exposure. ...
Introduction: Cold water exposure poses a unique physiological challenge to the human body. Normally, water submersion increases activation of parasympathetic tone to induce bradycardia in order to compensate for hemodynamic shifts and reduce oxygen consumption by peripheral tissues. However, elevated stress, such as that which may occur due to prolonged cold exposure, may shift the sympatho-vagal balance towards sympathetic activation which may potentially negate the dive reflex and impact thermoregulation.
Objective: To quantify the acute stress response during prolonged extreme cold water diving and to determine the influence of acute stress on thermoregulation.
Materials and Methods: Twenty-one ( n = 21) subjects tasked with cold water dive training participated. Divers donned standard diving equipment and fully submerged to a depth of ≈20 feet, in a pool chilled to 4°C, for a 9-h training exercise. Pre- and post-training measures included: core and skin temperature; salivary alpha amylase (AA), cortisol (CORT), osteocalcin (OCN), testosterone (TEST) and dehydroepiandosterone (DHEA); body weight; blood glucose, lactate, and ketones.
Results: Core, skin, and extremity temperature decreased ( p < 0.001) over the 9-h dive; however, core temperature was maintained above the clinical threshold for hypothermia and was not correlated to body size ( p = 0.595). There was a significant increase in AA ( p < 0.001) and OCN ( p = 0.021) and a significant decrease in TEST ( p = 0.003) over the duration of the dive. An indirect correlation between changes in cortisol concentrations and changes in foot temperature ( ρ = -0.5, p = 0.042) were observed. There was a significant positive correlation between baseline OCN and change in hand temperature ( ρ = 0.66, p = 0.044) and significant indirect correlation between changes in OCN concentrations and changes in hand temperature ( ρ = -0.59, p = 0.043).
Conclusion: These data suggest that long-duration, cold water diving initiates a stress response—as measurable by salivary stress biomarkers—and that peripheral skin temperature decreases over the course of these dives. Cumulatively, these data suggest that there is a relationship between the acute stress response and peripheral thermoregulation.
... Increased hair cortisol levels were found in various contexts (e.g., endurance athletes [42][43][44], shift work [21], sleep and mental disorders [45], unemployment [46], chronic pain [47], or major life events [48]). Long-term elevations in serum [49] and hair cortisol [50] have been also reported during stressful military captivity training. Meanwhile, longitudinal research on basic military training at the beginning of military service reports controversial findings: in Boesh et al. [26], research on Swiss conscripts reports that basic military training has no effect on cortisol concentration, while Gifford et al. [50] conducted research on UK cadets and indicated an increase in the cortisol concentration during basic military training. ...
This study aimed to analyse the association between endogenous hair steroid hormones as reliable biological indicators of an individual’s stress level and the social environmental factors experienced during military training that are manifested at the beginning of compulsory military service. Hair steroid hormone concentrations—cortisol, cortisone, dehydroepiandrosterone (DHEA), and testosterone—in a group of 185 conscripts were measured using the ultra-high performance liquid chromatography-tandem mass spectrometry method. Six subjective social environmental factors in the military—attitude towards the military and military service, adaptation to the military environment, team, task, and norm cohesion, as well as psychological (un)safety in the group—were evaluated using military-specific research questionnaires. Weak but significant negative correlations were identified between cortisol and adaptation (r = −0.176, p < 0.05), attitude (r = −0.147, p < 0.05) as well as between testosterone and task cohesion (r = −0.230, p < 0.01) levels. Additionally, a multiple forward stepwise regression analysis highlighted that cortisone variation might be partially explained by task cohesion; the DHEA—determined by psychological (un)safety in the group, attitude towards the military and military service, and norm cohesion; and the testosterone—determined by task cohesion and adaptation to the new military environment. The results of this study suggest that subjective measures of social factors can be used to predict hair steroid hormone levels as objective measures of the chronic stress perceived by conscripts during their basic military training.
... In addition, Forsblad-d' Elia et al. prescribed 50 mg oral DHEA daily for women with sjogren syndrome; they reported dry mouth symptom improvement [12]. Taylor et al. concluded that acute stress can elevate the serum levels of DHEA-S as cortisol does [17]. Anete Rejane et al. in an evaluation reported no significant difference in the salivary level of DHEA-S between patients with RAS and healthy controls [18]. ...
Background
In this study, we aimed to evaluate the sex hormonal serum level in patients with recurrent aphthous stomatitis and compare them with healthy participants.
Methods
This cross-sectional study was done on patients with recurrent aphthous stomatitis who had referred to Shiraz Dental Faculty, Oral and Maxillofacial Medicine Department during 2018–2019. The non -menopause women with recurrence of at least 3 lesions per year were enrolled in this study. The mean serum level of FSH, LH, PRL (prolactin), testosterone, DHT (Dihydrotestosterone), DHEA-S (Dehydroepiandrosterone sulfate), estradiol and progesterone of 30 participants in each group of case and control were measured and compared. The data were analyzed by SPSS version 18 and independent T-test, Mann–Whitney U test, Spearman’s correlation coefficient test, Chi-square test and Fisher’s test.
Results
The mean serum level of DHEA-S in patients with recurrent aphthous stomatitis (RAS) was significantly lower than the control group ( p value = 0.02). In addition to DHEA-S, the mean serum level of testosterone was lower in the evaluation group although this difference was not significant ( p value = 0.057). Considering the effect of age on the mean serum level of sex hormones, our results revealed that only DHEA-S mean serum level was decreased by increasing the age of participants in patients with RAS ( p value = 0.018). The number of participants with abnormal range of testosterone ( p value < 0.0001) and progesterone ( p value = 0.037) serum level was significantly more in patients with RAS. The frequency of RAS in a year did not show a significant relationship with the serum level of the evaluated hormones.
Conclusion
The patients with RAS had a lower serum level of DHEA-S. The mean serum level of testosterone and progesterone was significantly abnormal in RAS patients.
... Special Forces Assessment and Selection (SFAS), Basic Underwater Demolition/SEALs (BUD/S)) (Farina et al., 2019;Henning et al., 2014;Ledford et al., 2020), and survival training (i.e. Survival, Evasion, Resistance, and Escape [SERE]) (Lieberman et al., 2016;Morgan et al., 2001;Morgan et al., 2002;Suurd Ralph, Vartanian, Lieberman, Morgan, & Cheung, 2017;Szivak et al., 2018;Taylor et al., 2007) that examine biomarker profiles with respect to physical, cognitive, and psychological performance. In the subsequent sections, we will detail biomarkers across neuroendocrine, inflammatory, anabolic, and growth factor domains that have been associated with various aspects of military performance to better elucidate the biological basis of a resilient soldier. ...
... Dehydroepiandrosterone (DHEA) is an endogenous hormone and precursor to testosterone that modulates the negative consequences of elevated cortisol, providing beneficial behavioural and neurotrophic effects (Morgan et al., 2004;Morgan et al., 2009;Taylor et al., 2007). DHEA is secreted by the adrenal cortex and can be further converted to dehydroepiandrosterone sulfate (DHEA-S) by sulfotransferase in the adrenals, liver, and small intestine, which accounts for the majority of DHEA in circulation due to a longer biological half-life (15-30 mins vs. 7-10 h, respectively) (Morgan et al., 2009). ...
... DHEA has also been studied extensively in military survival trainings (Morgan et al., 2004;Morgan et al., 2009;Taylor et al., 2007;Taylor et al., 2012). Morgan et al. (2004) reported a significant increase in DHEA(S) concentrations from baseline in response to survival training, which remained elevated at 24-h post training. ...
Adaptation to military operational stress is a complex physiological response that calls upon the sympathetic nervous system (SNS), hypothalamic pituitary adrenal (HPA) axis and immune system, to create a delicate balance between anabolism and catabolism and meet the demands of an ever-changing environment. As such, resilience, the ability to withstand and overcome the negative impact of stress on military performance, is likely grounded in an appropriate biological adaptation to encountered stressors. Neuroendocrine [i.e. cortisol, epinephrine (EPI), norepinephrine (NE), neuropeptide-Y (NPY), and brain derived neurotropic factor (BDNF)], inflammatory [i.e. interleukin 6 (IL-6), IL-1β, IL-4, IL-10 and tumor necrosis factor (TNF)-α], as well as growth and anabolic [i.e. insulin-like growth factor-I (IGF-I), testosterone, and dehydroepiandrosterone (DHEA)] biomarkers independently and interactively function in stress adaptations that are associated with a soldier’s physical and psychological performance. In this narrative review, we detail biomarkers across neuroendocrine, inflammatory, and growth stimulating domains to better elucidate the biological basis of a resilient soldier. The findings from the reviewed studies indicate that military readiness and resiliency may be enhanced through better homeostatic control, better regulated inflammatory responses, and balanced anabolic/catabolic processes. It is unlikely that one class of biomarkers is better for assessing physiological resilience. Therefore, a biomarker panel that can account for appropriate balance across these domains may be superior in developing monitoring frameworks. Real-time physiological monitoring to assess biomarkers associated with resilience will be possible pending more sophisticated technologies and provide a field-expedient application for early identification and intervention of at-risk soldiers to improve military resiliency.
... Although we could not exclude the possibilities of unmeasured confounding factors, such as psychological stress (41), our findings imply the need of implementing blood pressure intervention for recruits during their academy training. In fact, despite a lack of direct evidence from fire academy training, previous research on military training found increased levels of cortisol and other stress hormones after the participants completed the training (42), which could lead to elevated blood pressure (43). Moreover, our study confirms that the occupational hazard of career firefighting includes an environment that paradoxically promotes reduced fitness and obesity (3,8,44). ...
Purpose:
To investigate changes in firefighter recruits' select health and fitness measurements, from academy training through the early probationary firefighter period.
Methods:
Firefighter recruits from two New England fire academies were followed prospectively from enrollment at the academy, to graduation after 15-16 week training programs, and then for an average of eight months as probationary firefighters. The participants' demographic, lifestyle, and mental health information were collected using a questionnaire. Body mass index (BMI), percent body fat, blood pressure, and push-ups were also measured at each time point. Furthermore, the academies tested the recruits on selected fitness measures (push-ups, pull-ups, and 1.5-mile running time) at academy entry, mid-training, and at graduation.
Results:
Ninety-two recruits consented and were included in the analyses. The recruits' percent body fat significantly decreased (median: 21.0% to 18.2%) from baseline to graduation and push-up capacity significantly improved (median: 34 to 53/minute) in the same period, along with pull-ups and 1.5-mile running time. However, the recruits' blood pressure, both systolic and diastolic, increased significantly by an average of 3 mmHg during the training. Those completing probationary follow-up (45 out of 92 recruits) showed that most health/fitness improvements declined after graduation. From academy graduation through probationary follow-up, recruits' physical activity decreased and TV screen time increased significantly, leading to a lower healthy lifestyle score (median: 4 to 3). After multivariate adjustments, the recruits' diastolic blood pressure increased by 2 mmHg per measuring time throughout the study period.
Conclusion:
Fire academy training improved recruits' select health and fitness measurements, but the benefits dissipated as probationary firefighters, and blood pressures increased throughout the study period. Further interventions are warranted regarding blood pressure and to maintain training benefits after joining fire departments.
... In a series of studies of Norwegian men and women undergoing an intensive 5-day military training course, the combination of physical and mental strain under sleep restriction led to marked suppression of the HPG axis, as well as the HPA and thyroid axes (Opstad, 2001). Four-week survival, evasion, resistance and extraction (SERE) training is associated with elevated cortisol levels compared with non-psychologically stressed controls (Taylor et al., 2007b); cortisol was elevated in response to a variety of simulated interrogation techniques encountered during SERE training (Lieberman et al., 2016a). Adaptations like these are transient and resolve over days to weeks with resumption of normal eating, sleeping and rest . ...
... Sustained elevations in serum cortisol have been reported following stressful military captivity training(Taylor et al., 2007b). Low concentrations of hair and saliva cortisol in response to social stress predict subsequent development of post-traumatic stress disorder during military deployments(Steudte-Schmiedgen et al., 2015).Variations in cortisol concentrations have complex and multidimensionalassociations with a variety of biological and psychological disorders. ...
