Work duration does not affect cortisol output in experienced firefighters performing live burn drills

Physiological Stress Responses to a Live-Fire Training Evolution in Career Structural Firefighters

OBJECTIVE

This study assessed firefighters' physiological stress response to a live fire training evolution (LFTE).

METHODS

Seventy-six ( n = 76) firefighters completed an LFTE. Salivary samples were collected pre-, immediately post, and 30-min post-LFTE and analyzed for α-amylase (AA), cortisol (CORT), and secretory immunoglobulin-A (SIgA).

RESULTS

Concentrations of AA, CORT, and SIgA were elevated immediately post LFTE versus pre (P<0.001) and 30-min post (P<0.001). Cohen's d effect size comparing pre and immediately-post means were 0.83, 0.77, and 0.61 for AA, CORT, and SIgA and were 0.54, 0.44, and 0.69 for AA, CORT, and SIgA, comparing immediately-post and 30-min post, respectively.

CONCLUSIONS

These data demonstrate the stress response and activation of the hypothalamic-pituitary-adrenal/sympathetic-adreno-medullar axis and immune system immediately after real-world firefighting operations. Future work is needed to understand the impact of elevated stress biomarkers on firefighter performance and disease risk.

Firefighters' occupational exposure: Contribution from biomarkers of effect to assess health risks

Firefighting is physically and physiologically exhausting besides encompassing exposure to toxic fire emissions. Biomonitoring studies from the past five years have been significantly contributing to characterize the occupational-related health effects in this group of professionals and to improve risk assessment. Therefore, this study gathers and critically discusses the most characterized biomarkers of effect (oxidative stress, DNA and protein damage, stress hormones, inflammation, and vascular, lung, and liver injury), including those potentially more promising to be explored in future studies, and their relation with health outcomes. Various studies proved an association between exposures to fire emissions and/or heat and significantly altered values of biomarkers of inflammation (soluble adhesion molecules, tumor necrosis factor, interleukins, and leucocyte count), vascular damage and tissue injury (pentraxin-3, vascular endothelial growth factor, and cardiac troponin T) in firefighting forces. Moreover, preliminary data of DNA damage in blood, urinary mutagenicity and 8-isoprostaglandin in exhaled breath condensate suggest that these biomarkers of oxidative stress should be further explored. However, most of the reported studies are based on cross-sectional designs, which limit full identification and characterization of the risk factors and their association with development of work-related diseases. Broader studies based on longitudinal designs and strongly supported by the analysis of several types of biomarkers in different biological fluids are further required to gain deeper insights into the firefighters occupational related health hazards and contribute to implementation of new or improved surveillance programs.

Wayfinding of Firefighters in Dark and Complex Environments

Firefighters searching in dark and complex environments might lose their orientation and endanger themselves at the fireground. This study conducted experiments in the Training Facility of the New Taipei City Fire Department (NTFD), Taiwan. The objective of the experiments was to analyze the profile of each firefighter by a 13-factor self-report survey and their wayfinding time in dark and complex environments (DCEs). The results showed that age might be a marginally significant factor, and fear of confinement might be a significant factor that could affect firefighters' wayfinding time in the DCEs. The findings could provide strategies for improving the safety of firefighters working in such environments.

Paediatric dentists' stress during dental care for children under sedation: a cross-sectional study

PURPOSE

The knowledge of the stress related to the practice of paediatric dentistry is scarce. The aim of this study was to verify the stress perceived by paediatric dentists related to young children's dental treatment under sedation and their association with child's behaviour and other independent variables.

METHODS

A cross-sectional repeated measures study was performed with four paediatric dentists who treated 81 sedated preschoolers. Paediatric dentists reported their stress at the end of the session using the visual analog scale (VAS 0-100 mm). Samples of saliva were collected to measure the dentists' salivary cortisol level throughout the dental session. The sessions of dental treatment were video recorded for evaluation of the child's behaviour. Children's behaviour was assessed using the Ohio State University Behavioral Rating Scale (OSUBRS). The association between the VAS scores and the other variables was verified using bivariate tests and generalised estimating equation (alpha 0.05).

RESULTS

Paediatric dentists felt slightly stressed in most of the sessions (VAS median 7 points; minimum 0, maximum 97 points). VAS associated with the struggling behaviour of the child (B 0.53; 95%CI 0.32-0.74; p ≤ 0.001) and the time since dentist's graduation (B - 1.41, 95% CI - 1.87 to - 0.94; p ≤ 0.001) but not with dentist's salivary cortisol (rho - 0.053, p = 0.639).

CONCLUSION

The more frequent the child's struggling behaviour during dental treatment and the shorter the time elapsed since the professional's graduation, the higher the level of objectively and subjectively measured stress of the paediatric dentist during the dental procedure.

Effect of Combat Stress in the Psychophysiological Response of Elite and Non-Elite Soldiers

We aimed to analyse the effect of combat stress in the psychophysiological responses of elite and non-elite soldiers. We analysed heart rate, cortical arousal, skin temperature, blood lactate concentration and lower body muscular strength before and after a tactical combat simulation in 40 warfighters divided in two groups: elite (n: 20; 28.5 ± 6.38 years) and non-elite (n:20; 31.94 ± 6.24 years) group. Elite presented a significantly higher lactate concentration after combat than non elite soldiers (3.8 ± 1.5 vs 6.6 ± 1.3 mmol/L). Non-elite soldiers had a higher heart rate pre and post the simulation than elite (82.9 ± 12.3 vs 64.4 ± 11. pre non elite and elite respectively; 93.0 ± 12.8 vs 88 ± 13.8 bpm post non elite and elite respectively). Elite soldiers presented higher lower muscular strength than elite in all test and before and after the combat simulation. Cortical arousal was not modified significantly in both groups. We conclude elite soldiers presented in combat a higher anaerobic metabolism activation and muscular strength than non-elite soldiers, but cardiovascular, cortical, and muscular strength manifestation presented the same response in both elite and non-elite soldiers.