Psychological resilience and high-intensity functional training to strengthen mental health among northern Arizona career firefighters

Santos, Anthony Charles (2023) Psychological resilience and high-intensity functional training to strengthen mental health among northern Arizona career firefighters. Doctoral thesis, Northern Arizona University.

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Abstract

Almost one in three firefighters develop mental health disorders at some point during their careers, a rate double that in the general population. Frequent exposures to potentially traumatic situations can contribute to symptoms of these disorders, two of the most common being depression and post-traumatic stress disorder (PTSD). While various psychological interventions have been implemented among this group, reports of their effectiveness include mixed results. To this end, the current study endeavored to test the effectiveness of a 12-week intervention combining occupationally-tailored high-intensity functional training (HIFT) and psychological resilience training (RES) at reducing depressive and post-traumatic stress symptoms (PTSS), as well as increasing psychological resilience and mental wellbeing, in career firefighters. The primary aim of this study was to observe change over time for each mental health outcome, while secondary aims investigated (1) potential mechanisms of changes across mental health outcomes; (2) the impact of adherence to intervention components, combined and individually, on changes to mental health outcomes; and (3) the impact of intervention adherence on anthropometrics and simulated job-task performance. Thirty career firefighters completed four mental health measurements over 17 weeks while anthropometrics (i.e., bodyweight, BMI, lean body mass, and percent body fat) and physical performance (i.e., number of stations completed in 20 minutes during an 8-station simulated job-task circuit workout [T-CAC]) were measured pre- and post-intervention. Weekly intervention practices consisted of three HIFT workouts and four RES practices provided by The First Twenty®. Pre to post comparisons were made via repeated-measures t-tests while multilevel modeling (MLM) assessed longitudinal changes across all outcomes. Results indicated that, on average, larger increases to psychological resilience over the intervention period correlated with decreased PTSS at post-intervention, and higher PTSS and depressive symptom scores at baseline related to higher scores at post-intervention as well. Significant mean differences were also observed for T-CAC stations completed, PTSS, and psychological resilience between pre- and post-intervention. MLM results indicated significant effects of fire department rank and years of service on mental wellbeing, as well as significant effects of intervention adherence on depressive symptoms, body weight, and lean body mass. A wildfire (i.e., Tunnel Fire) also ignited in the area during the intervention period, which produced significant effects on mental health and T-CAC performance as well. Overall, future interventions should actively and frequently engage firefighters, integrate with daily operations as much as possible, and employ culturally-relevant communications and practices to explore the links between physical and mental health.

Item Type:	Thesis (Doctoral)
Publisher’s Statement:	© Copyright is held by the author. Digital access to this material is made possible by the Cline Library, Northern Arizona University. Further transmission, reproduction or presentation of protected items is prohibited except with permission of the author.
Keywords:	Exercise; Firefighters; Intervention; Mental health; Psychological resilience; PTSD
Subjects:	B Philosophy. Psychology. Religion > BF Psychology
MeSH Subjects:	F Psychiatry and Psychology > F03 Mental Disorders
NAU Depositing Author Academic Status:	Student
Department/Unit:	Graduate College > Theses and Dissertations College of Social and Behavioral Science > Institute for Human Development
Date Deposited:	28 Jul 2026 17:49
Last Modified:	28 Jul 2026 17:53
URI:	https://openknowledge.nau.edu/id/eprint/6324

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