Journal of health research in community

Introduction
Introduction: Firefighting is recognized as one of the most difficult and stressful service professions worldwide. Firefighters are constantly exposed to numerous physical and psychological hazards due to their rescue and firefighting missions. High workload, irregular working hours, and shift work are among the factors that can lead to occupational fatigue and ultimately work–family conflict. Considering the critical role of firefighters in ensuring safety and providing emergency relief, and considering the physical, psychological, and social pressures arising from the nature of their occupation, it is essential to identify factors affecting work–family conflict in this population. The present study aimed to investigate the relationship between workload and occupational fatigue with work–family conflict among firefighters in Sabzevar and Esfarayen cities.

Methods
 This descriptive-analytical cross-sectional study was conducted in 2025. Based on the study by Bolghanabadi et al. [7] with a correlation coefficient of -0.246 between mental workload and quality of work life, a significance level of 5%, and a test power of 80%, the sample size was calculated as 128 participants. Considering a 10% attrition rate, the final sample size was determined as 142 participants. The statistical population included all firefighters working in Sabzevar and Esfarayen cities. Multi-stage sampling was employed; first, fire stations were classified based on city and type of mission, and then a number of stations were randomly selected. In the next stage, participants were selected from the personnel list of each selected station using a random number table and simple random sampling. The inclusion criteria were at least one year of work experience as a firefighter; no history of psychiatric disorders or Alzheimer’s disease; no physical or mental disabilities; and provision of informed consent to participate. The measurement instruments included three questionnaires: the NASA-TLX Workload Questionnaire (score range: 0–100), the Swedish Occupational Fatigue Inventory (score range: 0–200), and the Carlson et al.’s Work–Family Conflict Questionnaire (score range: 18–90). After approval was obtained from the university ethics committee and written informed consent was obtained from all participants, the questionnaires were distributed at the end of their work shifts. The Pearson correlation coefficient and multiple linear regression (Enter method) were used to examine relationships between variables. Data were analyzed using SPSS software, version 22.

Results
A total of 142 firefighters from Sabzevar and Esfarayen participated in the study. Their mean age was 36.84±6.71 years, and their mean work experience was 9.53±6.74 years. The majority held a bachelor’s degree (62.67%) and were married (82.39%). The mean scores were 63.12±10.07 for workload (high level), 71.12±18.17 for occupational fatigue (moderate level), and 43.60±7.43 for work–family conflict (moderate level). Among the workload components, physical demand had the highest mean score (73.90±20.41) and frustration had the lowest (49.57±20.20). For occupational fatigue, lack of energy had the highest mean score (22.58±8.83), and lack of motivation had the lowest (8.98±6.47). For work–family conflict, time-based work–family conflict had the highest mean score (10.26±2.79), and behavior-based family–work conflict had the lowest (4.58±2.12). The frequency distribution showed that 23.9% of participants had low, 52.8% had moderate, 19.0% had high, and 4.2% had very high levels of work–family conflict. Pearson correlation analysis revealed significant positive correlations between work–family conflict and workload (r(140):0.44, P<0.001) and occupational fatigue (r=(140):0.51, P<0.001), but no significant correlations with age (P=0.432), work experience (P=0.602), or education (P=0.081). Multiple linear regression showed that the final model was significant and explained 43% of the variance in work–family conflict (R²=0.430, P<0.001). Workload (β=0.34, B= 0.253) and occupational fatigue (β=0.481, B=0.199) were significant positive predictors (P<0.001), while age (P=0.557), work experience (P=0.698), and education (P=0.297) were not significant. Based on squared semi-partial correlations, workload and occupational fatigue uniquely explained 10.9% and 21.5% of the variance in work–family conflict, respectively. 

Conclusion
Workload and occupational fatigue are positively and significantly associated with work–family conflict among firefighters. High workload in this group was primarily driven by physical demands, consistent with the operational field nature of firefighting [4]. The moderate level of occupational fatigue, with predominance of the lack of energy component, reflects cumulative pressure from irregular shift work patterns and the physical and psychological demands of missions, aligning with previous studies [7, 12]. The predominance of time-based and strain-based work–family conflict components over family–work conflict components indicates that occupational demands and pressures play a greater role than family responsibilities in creating role conflict [30, 31]. The lack of significant relationships between demographic variables (age, work experience, and education) and work–family conflict highlights the dominant role of structural occupational factors over individual characteristics in this profession [7, 33]. According to the job demands-resources model, high workload, as a chronic job demand, depletes an individual’s cognitive, emotional, and temporal resources, and when these resources are insufficient for simultaneously managing work and family duties, work–family conflict emerges [13]. These findings emphasize the importance of addressing workload management and occupational fatigue in occupational health promotion programs and implementing organizational interventions, such as revising shift schedules, limiting overtime hours, and providing psychological support programs.

Ethical Considerations
Compliance with ethical guidelines
This study received ethics approval from Esfarayen Faculty of Medical Sciences (Code: IR.ESFARAYENUMS.REC.1403.026). Written informed consent was obtained from all participants, and confidentiality of their data was guaranteed. 

Funding
This research was funded by Esfarayen Faculty of Medical Sciences (Grant No.: 1403/29P/106).

Authors contributions
Conceptualization, methodology, validation: Seyed Hojat Mousavi Kordmiri, Khadijeh Gheysar Koushki, and Ali Ansari Moghadam; Investigation, resources, writing: Khadijeh Gheysar Koushki and Fatemeh Kargar Ardizi; Data analysis and interpretation: Seyed Hojat Mousavi Kordmiri and Marzieh Mahmudimanesh; Editing & review: Khadijeh Gheysar Koushki. All authors read and approved the final version of the manuscript.

Conflicts of interest
The authors reported no conflicts of interest.

Acknowledgments
The authors sincerely thank the firefighters from Sabzevar and Esfarayen counties who participated in this study for their cooperation.

References

1. Zahari ASM, Mahmud YH, Baniamin RMR. Factors affecting job satisfaction: A case study at Fire and Rescue Department of Malaysia Terengganu (FRDMT) fire fighters. Int J Econ Manag. 2019; 1(3):24-39. [Link]
2. Darvishi E, Sadeghi F, Saed Panah K. [Evaluation of effective factors on occupational stress in firefighting personnel (Persian)]. J Health Syst Res. 2015; 11(1):184-92. [Link]
3. Mohammadi M, Mazloumi A, Nasl Seraji J, Zeraati H. Designing questionnaire of assessing mental workload and determine its validity and reliability among ICUs nurses in one of the TUMS’s hospitals. J Sch Public Health Inst Public Health Res. 2013; 11(2):87-96. [Link]
4. Smith TD, Hughes K, DeJoy DM and Dyal M-A. Assessment of relationships between work stress, work-family conflict, burnout and firefighter safety behavior outcomes. Saf Sci. 2018; 103:287-92. [DOI:10.1016/j.ssci.2017.12.005]
5. Nasrul RN, Zainal VR, Hakim A. Workload, Work Stress, and Employee Performance: A Literature Review. Dinasti Int J Educ Manag Soc Sci. 2023; 4(3):415-22. [Link]
6. García-Heras F, Gutiérrez-Arroyo J, Rodríguez-Medina J, Carballo-Leyenda B, Sánchez-Collado P, Villa-Vicente G,  et al. Determinants of Health and Performance in Wildland Firefighters: A Narrative Review. J Funct Morphol Kinesiol. 2025; 10(1):80. [DOI:10.3390/jfmk10010080] [PMID]
7. Bolghanabadi S, Mousavi Kordmiri SH, Mahmodi A, Mehdiabadi S. [The effect of mental workload on stress and quality of work life of firefighters (Persian)]. J Sabzevar Univ Med Sci. 2019; 26(5):547-53. [Link]
8. Askari A, Feyzi V, Farhadi A, Dashti A, Poursadeqiyan M, Salehi Sahl Abadi A. Examining the impact of occupational stress and shift work schedules on the cognitive functions among firefighters in normal condition. Work. 2025; 81(2):2662-9.[DOI:10.1177/10519815251320268] [PMID]
9. Paramita NKS, Suwandana IGM. Effect of job stress, work conflict, and workload on employees’ performance. Eur J Bus Manag Res. 2022; 7:125-8. [DOI:10.24018/ejbmr.2022.7.4.1508]
10. Mehrifar Y, Pirami H, Nikooyan F, Samimi K, Avarseji A, Ramezanifar S. The correlation between job stress, burnout, and cognitive performance in Iranian firefighters: A cross-sectional study. Work. 2025; 80(1):407-15. [DOI:10.3233/WOR-240056] [PMID]
11. Shamsi V, Hemmati M, Enayat H. [A systematic review of work-family conflict studies in Iran (Persian)]. Sociol Soc Inst. 2022; 9(19):59-84. [DOI: 10.22080/ssi.2022.23099.1978]
12. Smith TD, DeJoy DM, Dyal MA, Huang G. Impact of work pressure, work stress and work-family conflict on firefighter burnout. Arch Environ Occup Health. 2019; 74(4):215-22. [DOI:10.1080/19338244.2017.1395789] [PMID]
13. Bakker AB, Demerouti E. Job demands-resources theory: Taking stock and looking forward. J Occup Health Psychol. 2017; 22(3):273-85. [DOI:10.1037/ocp0000056] [PMID]
14. Hart SG, Staveland LE. Development of NASA-TLX (Task Load Index): Results of Empirical and Theoretical Research. In: Hancock PA, Meshkati N, editors. Human mental workload. Amsterdam: North-Holland; 1988. [DOI:10.1016/S0166-4115(08)62386-9]
15. Javadpour F, Keshavarzi S, Choobineh A, Aghabaigi M. [Validity and reliability of the Swedish Occupational Fatigue Inventory (SOFI-20) among Iranian working population (Persian)]. Iran J Ergon. 2015; 3(1):50-8. [Link]
16. Motesharrei MH, Neisi AK, Arshadi N. [The test of validity and reliability of Carlson, Kacmar & Williams work-family conflict questionnaire (2000) (Persian)]. J Anal Cogn Psychol. 2013; 4(14):65-73. [Link]
17. Rajabi G, Makki E and Aslani K. [Reliability and validity of the Persian version of Work-Family Conflict Scale (Persian)]. Payesh. 2020; 19(4):435-44.  [DOI:10.29252/payesh.19.4.435]
18. Reyes JEA, Bernados JNP, Cawaling J, Cruz DEU, De Leon JK, Taguiam AN. Assessing the Influence of Mental Workload and Stress on Firefighters in Manila Using the NASA TLX: Implications for Performance and Well-Being. In: In: Jin S, Kim JH, Kong YK, Park J, Yun MH, editors. Proceedings of the 22nd Congress of the International Ergonomics Association, Volume 3. IEA 2024. Springer Series in Design and Innovation, vol 41. Singapore: Springer; 2025. [DOI:10.1007/978-981-96-9330-6_56]
19. Roja Z, Kalkis V, Kalkis H, Pencis I. Assessment of firefighters-rescuers’ work severity in relation with interaction between physical and mental load. Proc Latv Acad Sci B Nat Exact Appl Sci. 2009; 63(6):264-70. [DOI:10.2478/v10046-010-0002-0]
20. Zeraat Herfeh F, Shamsi Nezhad M, Rahmati A. Psychological consequences of firefighters' working conditions: A qualitative study. Occup Med Q J. 2021; 13(3):77-91. [DOI:10.18502/tkj.v13i3.8201]
21. Maulana NA, Prasetyo TB, Susanto B, Hermawan A. Analysis of the relationship between workload and firefighters’performance in the firefighting and rescue service of cirebon district using Structural Equation Modeling (Sem): Case Study Of The Weru Sector. J Scientech Res Dev. 2025; 7:524-39. [DOI:10.56670/jsrd.v7i1.922]
22. Lee KS. [Association between job stress and fatigue symptoms among fire-fighting officials (Korean)]. J Korea Acad Ind Coop Soc. 2021; 22(2):496-506. [DOI:10.5762/KAIS.2021.22.2.496]
23. Takeyama H, Itani T, Tachi N, Sakamura O, Murata K, Inoue T, et al. Effects of shift schedules on fatigue and physiological functions among firefighters during night duty. Ergonomics. 2005; 48(1):1-11. [DOI:10.1080/00140130412331303920] [PMID]
24. Schmitz AN, Giuliani-Dewig HK, Laffan MR, Trivisonno AJ, Gerstner GR, Mota JA, et al. Work-related Fatigue: Relationship between Perceived and Performance Fatigability in Career Firefighters. J Occup Environ Med. 2025; 67(2):110-4. [DOI:10.1097/jom.0000000000003282]
25. Marvin G, Schram B, Orr R, Canetti EF. Occupation-induced fatigue and impacts on emergency first responders: A systematic review. Int J Environ Res Public Health. 2023; 20(22):7055. [DOI:10.3390/ijerph20227055] [PMID]
26. Giuliani HK, Gerstner GR, Mota JA, Ryan ED. Influence of demographic characteristics and muscle strength on the occupational fatigue exhaustion recovery scale in career firefighters. J Occup Environ Med. 2020; 62(3):223-6. [DOI:10.1097/JOM.0000000000001806] [PMID]
27. Dennison KJ, Mullineaux DR, Yates JW, Abel MG. The effect of fatigue and training status on firefighter performance. The J Strength Cond Res. 2012; 26(4):1101-9.  [DOI:10.1519/JSC.0b013e31822dd027] [PMID]
28. Basińska BA, Wiciak I. Fatigue and professional burnout in police officers and firefighters. Intern Secur. 2012; 4(2):265-74.[Link]
29. Halbesleben JR. The influence of shift work on emotional exhaustion in firefighters: The role of work-family conflict and social support. Int J Workplace Health Manag. 2009; 2(2):115-30. [DOI:10.1108/17538350910970200]
30. Simmons JS. The Impact of Household Preparedness and Work-Family Conflict on Medic-Firefighter Ability and Willingness to Respond for Duty in a Disaster. [PhD dissertation]. Jacksonville (AL): Jacksonville State University; 2024. [Link]
31. Lee N, Lee HJ. Home Difficulties Experienced by Male Firefighters in South Korea: A Qualitative Study on Work-Family Conflict. Healthcare (Basel). 2025; 13(18):2300.  [DOI:10.3390/healthcare13182300] [PMID] [PMCID]
32. Shreffler KM, Meadows MP, Davis KD. Firefighting and fathering: Work-family conflict, parenting stress, and satisfaction with parenting and child behavior. Fathering. 2011; 9(2):169-88. [DOI:10.3149/fth.0902.169]
33. Vinnikov D, Tulekov Z, Akylzhanov A, Romanova Z, Dushpanova A, Kalmatayeva Z. Age and work duration do not predict burnout in firefighters. BMC Public Health. 2019; 19(1):308. [DOI:10.1186/s12889-019-6643-2] [PMID] [PMCID]
34. Wu TJ, Yuan KS, Yen DC, Xu T. Building up resources in the relationship between work-family conflict and burnout among firefighters: Moderators of guanxi and emotion regulation strategies. Eur J Work Organ Psychol. 2019; 28(3):430-41. [DOI:10.1080/1359432X.2019.1596081]
35. Dawson D, Mayger K, Thomas MJ, Thompson K. Fatigue risk management by volunteer fire-fighters: Use of informal strategies to augment formal policy. Accid Anal Prev. 2015; 84:92-8. [DOI:10.1016/j.aap.2015.06.008] [PMID]