|Original Article, Biomed Biopharm Res., 2023; 20(1):37-50
doi: 10.19277/bbr.20.1.308; PDF version [+]; Portuguese html [PT]
Relationship between weight status with sleep health, physical activity and perception of food consumption under stress among firefighters: a pilot study
Leandro Oliveira 1 ✉️, Carolina Oliveira 2, Madalena Martins 2, Madalena Silva 2, Sofia Martins 2, and Carina Rossoni 2,3
1 - CBIOS - Center for Biosciences & Health Technologies, Universidade Lusófona de Humanidades e Tecnologias, Campo Grande 376, 1749-024 Lisboa, Portugal
2 - Escola de Ciências e Tecnologias da Saúde da Universidade Lusófona, Av Campo Grande, 376, 1749-024, Lisboa, Portugal
3 - Universidade de Lisboa – Instituto de Saúde Ambiental da Faculdade de Medicina, Avenida Professor Egas Moniz, 1649-028 Lisboa - Portugal
Firefighters are a population group that is subject to stress and poorer sleep quality due to their professional activity. The aim of this cross-sectional pilot study was to explore the relationship between weight status and sleep health, physical activity, perception of dietary consumption, and stress among firefighters. The study was conducted in May 2022. An online questionnaire was developed using Google Forms® and shared through social media for data collection. A total of 30 firefighters participated in the study, with the majority being male (60.0%), over 40 years of age (56.7%), and residing in Lisbon (90.0%). The majority of participants were overweight (63.3%), walked for 4 days per week for about 30 minutes, and spent approximately 4 hours in sedentary activities. The median score for sleep health was 18 out of 30 points. Weight status was only positively correlated with age. These results suggest a possible need for the development of health programs targeting firefighters to improve their lifestyles and occupational health, with further studies needed with a larger sample size.
Keywords: weight status; sleep health; physical activity; consumption; firefighters
To Cite: Oliveira, L., Oliveria, C., Martins, M., Silva, M., Martins, S., Rossoni, C. (2023) Relationship between weight status with sleep health, physical activity and perception of food consumption under stress among firefighters: a pilot study. Biomedical and Biopharmaceutical Research, 20(1), 37-50.
Received 12/04/2023; Accepted 07/06/2023
Firefighters are exposed to several activities that pose significant short-term, medium-term, and long-term health risks. Among these risks inherent to the firefighter activity, we can highlight the development of cardiovascular diseases, respiratory diseases, musculoskeletal diseases, and cancer. Equally important is the higher likelihood of work-related accidents compared to the general population (1).
In Portugal, the latest data from the National Institute of Statistics shows that in 2021, there were 26,123 firefighters, of which 21,137 (80.9%) were male and 10,392 (60.2%) were volunteers (2). According to Decree-Law 247/2007, of June 27th, to professional firefighting bodies, among other activities, it is their responsibility to perform the following functions: firefighting; providing assistance to the population in case of fires, floods, collapses, and collisions, as well as in all accidents, disasters, or calamities; providing assistance to shipwrecked individuals; and performing first aid and health-related activities in the field of healthcare (3).
In order to perform their duties, firefighters must maintain good health and proper nutritional status. Firefighters with a high body mass index (BMI), body fat percentage (%), or waist circumference are at increased risk of injuries during service, (4), more days with reduced health (5) as well as a higher mortality rate while performing their duties due to cardiovascular diseases (6). In fact, many firefighters experience a significant weight gain due to an increase in body fat throughout their careers. (7). For example, a study that followed firefighters from Massachusetts between 1996 and 2001 found an increase in body mass index (BMI) from 29 kg/m2 to 30 kg/m2, with the prevalence of obesity increasing from 35% to 40% during that period (7). Another study reported that obese firefighters had a higher prevalence of hypertension, higher levels of total cholesterol, and lower levels of high-density lipoprotein concentration compared to non-obese firefighters (both volunteer and career) (8).
In addition, the fact that firefighters deal directly with people's lives requires them to be focused and alert for quick decision-making, which can have life or death consequences for the individuals they rescue (9). These situations can lead to post-traumatic stress disorder (PTSD) and chronic occupational stress (10). It is known that occupational stress affects not only employees but also organizations due to its implications: psychological (anxiety, depression, irritability, impaired decision-making, lack of concentration); physical (headaches, hypertension, cardiovascular, pulmonary, renal, musculoskeletal, and immune system disorders); and organizational (absenteeism, turnover, low productivity, job dissatisfaction, reduced performance) (9).
These consequences caused by occupational stress also have implications on firefighters' weight management. In a study of metropolitan Australian firefighters, food intake was largely determined by shift schedules, attitudes of colleagues, time, accessibility, and health considerations (11).
Several studies have pointed out a bidirectional relationship between dietary habits and sleep quality. Poor sleep quality can negatively affect dietary habits, resulting in low-nutrient quality food intake and increased appetite and energy intake (12). On the other hand, dietary choices can also influence sleep quality (13).
The aim of this study is to study the relationships between weight status, sleep health, physical activity, and perceived stress-related eating in a sample of Portuguese firefighters. Understanding these interactions can allow the development of tailored health-promoting interventions for this population. To date, no studies have been found in Portugal that outline and relate these lifestyle variables comprehensively in firefighters, making this research relevant to contribute to knowledge about the health and well-being of this specific population.
Materials and Methods
Study Design and Data Collection
This is a pilot cross-sectional study that included firefighters in Portugal who were 18 years of age or older, and excluded those who had been firefighters for less than 6 months.
Data collection was conducted using an online questionnaire, through the GoogleForms® platform, and all data were self-reported. The data collection questionnaire included the following sections: sociodemographic characteristics (gender, age, education level, marital status, anthropometric data); sleep quality; food consumption under stress; and physical activity.
The questionnaire was available during the month of May 2022 and was shared through Facebook® directly to firefighters, requesting their participation in the study as well as asking them to share it with their colleagues in the profession. Thus, a non-probabilistic snowball sampling method was used. Body mass index (BMI) was calculated using the formula weight (kg) / height2 (m) (14), and classified according to the World Health Organization criteria for adults (15).
Sleep health was assessed using the Satisfaction Alertness Timing Efficiency Duration (SATED) scale, validated for the Portuguese population (16). The scale assesses five core dimensions of sleep that have been consistently associated with various health outcomes, including sleep regularity, subjective satisfaction with sleep, alertness during waking hours, timing, efficiency, and sleep duration. In the original scale, each question is assigned a value of 0, 1, or 2 points, and the final score is calculated by summing the individual item scores, resulting in a total score that can range from 0 (poor sleep health) to 10 (good sleep health) (17). However, as mentioned by Buysse (17), other response options can be given using Likert scales. In this study, we chose to use the version validated in a sample of the Portuguese population (16), where a 6-point Likert scale was used (0 - never; 5 - always), resulting in a maximum final score of 30 points. The higher the score, the better the sleep health.
To assess the participants' perception of food consumption, smoking habits, and physical exercise under conditions of stress, they were asked to report their level of agreement (on a Likert-type scale ranging from 1 - strongly disagree to 5 - strongly agree) with the following statements: "When I feel stressed, I tend to consume more sweets"; "When I feel stressed, I tend to engage in more physical exercise"; "When I feel stressed, I tend to consume more fast food"; "When I feel stressed, I tend to smoke"; "When I feel stressed, I tend to eat more"; and "When I feel stressed, I tend to consume fewer fruits and vegetables."
Physical activity was assessed using the Portuguese version of the International Physical Activity Questionnaire (IPAQ) proposed by the World Health Organization, which provides information on the time spent walking, engaging in moderate and vigorous-intensity activities, and sedentary behavior over the past seven days (18). An open-ended question was also included to inquire about the reasons that hindered participation in physical exercise.
This study was conducted in accordance with the ethical guidelines established in the Declaration of Helsinki of 1964 and its subsequent amendments, or comparable ethical standards (19). Information about the study was provided to all volunteers, and informed consent was obtained, explaining in detail the study's objectives and protocol. Confidentiality and exclusive use of the collected data for the present study were assured, and the data were treated in a way that ensured anonymity.
The IBM SPSS Statistics software, version 26 for Windows, was used for the statistical analysis of this study. Descriptive statistics included calculating medians and percentiles (P25; P75), as well as absolute frequencies (n) and relative frequencies (%). Fisher's exact test was used to assess the independence between pairs of variables, while the Mann-Whitney test was used to compare mean ranks between independent samples. Spearman's correlation coefficient (r) was applied to evaluate the degree of association between pairs of continuous variables. The null hypothesis was rejected for a p-value < 0.05.
Results and Discussion
This study employed a pilot approach to investigate the relationship between body weight status, sleep health, physical activity, and perceived stress-related consumption in a sample of active Portuguese firefighters. The main findings of our study were: a high prevalence of overweight/obesity, low physical activity, poor sleep quality, and increased consumption of sweets associated with stress.
In Table 1, the sociodemographic characterization, weight status, and physical activity of the study participants are presented. Our sample consisted of 30 firefighters, with the majority being male (60.0%), over 40 years of age (56.7%), married (60.0%), residing in the Lisbon metropolitan area (90.0%), having completed secondary education (53.3%), and having another profession in addition to being firefighters (53.3%).
|Table 1 - Sociodemographic characterization, weight status and physical activity.|
Regarding weight status, the majority were classified as overweight - pre-obesity and obesity (63.3%). The high prevalence of overweight/obesity found in this study is consistent with that found in the Portuguese population (20), as well as a study conducted on Portuguese firefighters (21) which reported a prevalence of overweight of 62%. Furthermore, our results are also in line with other international studies in firefighters, such as those conducted in the United States (22), Brazil (23), and France (24), which report a high prevalence of overweight/obesity among firefighters.
Regarding physical activity, it was found that the participants engaged in walking four times a week for 35 minutes and engaged in vigorous activities one day a week for 60 minutes. In addition, they engaged in sedentary activities for 120 minutes daily. When asked about the reasons that hindered physical activity, the majority of firefighters reported work-related issues (excessive working hours, rotating shifts, among others) (36.7%), lack of time (36.7%), and dislike of physical activity or laziness (27.6%). Similar results to those reported in our study have been found in other studies with firefighters (22,25), and are also consistent with findings in the Portuguese population (26), where 73% of Portuguese individuals report never engaging in exercise or sports, with an additional 5% doing so only "rarely". In the case of Portuguese firefighters, it has also been reported that 49% do not engage in any physical activity (21).
These results deviate from the recommendations of the World Health Organization, which states that adults should engage in at least 150 to 300 minutes of moderate-intensity aerobic physical activity, or at least 75 to 150 minutes of vigorous-intensity aerobic physical activity, or an equivalent combination of moderate and vigorous-intensity physical activity throughout the week for substantial health benefits (27). In our study, low physical activity was observed among firefighters, including engaging in walks four days per week for approximately 35 minutes, and engaging in sedentary activities for about 270 minutes per day.
Physical activity in firefighters has been studied and identified as an important determinant of health (28,29). A study with firefighters from Cyprus (30) showed that physical activity is inversely associated with occupational stress and serves as an important mitigating factor for occupational stress in firefighters. According to a study with South Korean firefighters (31), a high perception of excessive workload, higher engagement in physically demanding tasks, higher frequency of occupational activities, and engagement in high-intensity physical activity were significantly correlated with an increased risk of insomnia.
Table 2 presents the assessment of sleep health according to the SATED scale. The majority of participants adopt an intermediate position on the SATED scale for most of its items. However, about 40% of participants mentioned "always" for the items "Can you stay awake all day without taking a nap?" and "Do you find yourself already asleep (or in bed) between two and four in the morning?". The median (25th percentile; 75th percentile) score on the SATED scale was 18 (8.0; 23.0), with a maximum score of 30 points. Indeed, the literature reports poor sleep quality among firefighters (32,33), which is consistent with our study and even more prevalent among firefighters who work night shifts (34). Poor sleep quality can affect cognitive functioning (e.g., processing speed, visomotor coordination, and reaction time), increasing the likelihood of poor job performance or injury (35).
|Table 2 - Sleep health assessment according to the SATED scale.|
Finally, in Table 3, the perception of consumption and practice of physical exercise under stress conditions is assessed. Approximately 50% of participants strongly disagree/disagree that they tend to engage in more physical exercise and consume more fast food when they feel stressed. Participants also mentioned strongly disagreeing/disagreeing that when they feel stressed, they tend to smoke (63.3%), eat more (46.6%), and consume fewer fruits and vegetables (40.0%). On the other hand, they mentioned agreeing/agreeing strongly that when they feel stressed, they tend to consume more sweets (43.4%). Correlation tests were also conducted between variables (age, BMI, SATED scale, and perception of consumption under stress conditions). It was found that higher age is positively correlated with higher BMI (r: 0.290; p: 0.041) and negatively correlated with the tendency to consume fast food (r: -0.427; p: 0.002) and eat more (r: -0.361; p: 0.010) when feeling stressed. Higher scores on the SATED scale are negatively correlated with the tendency to smoke when feeling stressed (r: -0.333; p: 0.018). Higher tendency to consume more sweets is positively correlated with the tendency to eat more (r: 0.783; p: <0.001), consume more fast food (r: 0.589; p: <0.001), and consume fewer fruits and vegetables (r: 0.516; p: <0.001) when feeling stressed. Higher tendency to smoke is positively correlated with the tendency to consume fewer fruits and vegetables (r: 0.342; p: 0.015) when feeling stressed. Higher tendency to eat more is positively correlated with the tendency to consume fewer fruits and vegetables (r: 0.466; p: <0.001) when feeling stressed.
|Table 3 - Perception of consumption and practice of physical exercise under stress conditions.|
Stress has also been associated with poor sleep quality (36) and increased consumption of calorie-dense foods, including fast food and sweets, and a reduction in healthy foods such as fruits and vegetables. In fact, according to a study, individuals under stress tend to consume foods that they normally avoid due to weight loss or health concerns (i.e., high-energy, high-fat snacks), reporting that consuming these foods makes them feel better (37). Another study found that individuals with higher stress levels tend to consume more sweets and fast food (38). This may provide a possible explanation for the correlations found in our study, where it was observed that a higher tendency to consume sweets was associated with a higher tendency to eat more, consume more fast food, and eat fewer fruits and vegetables when feeling stressed. Considering that firefighting is a profession associated with high levels of stress (39), and our sample showed a tendency towards consumption of unhealthy foods (such as sweets, high in sugars and energy) and low physical activity, the high prevalence of overweight found in our study is justified.
In order to perform their duties effectively, firefighters must maintain good health (1). However, in terms of occupational health for firefighters, only the "Health+" program was found, which aims to address physical activity, nutrition, and stress management. Additionally, a manual developed by the Directorate-General of Health and the National Authority for Civil Protection was also founded (1) to raise awareness among firefighters and fire departments about the importance of adopting a healthy lifestyle, no intervention programs specifically targeted at this population were found. Therefore, the results of this study highlight the need for the development and, above all, the implementation of health promotion programs tailored to this population.
Limitations and Future Directions
As any study, our work has some limitations. Firstly, its cross-sectional design does not allow for extrapolation of results. The small sample size (only 30 participants) is another limitation, although efforts were made to increase the sample size by sharing the questionnaire at different times on social media. Additionally, the self-reported nature of the anthropometric data is a limitation, and results should be interpreted with caution. For example, a study conducted in firefighters (men and women) in the USA (40) found that women tended to underestimate weight more than men, and men tended to overestimate height more than women. Furthermore, the use of snowball sampling for participant recruitment did not allow for control over sample composition or representativeness.
However, it is important to highlight that this is a pilot study that will serve as a foundation for larger-scale studies. Additionally, validated tools for the Portuguese population were used in this study. To our knowledge, this is the first study to investigate the relationship between weight status, sleep health, physical activity, and stress-related consumption in firefighters in Portugal.
Our study found that body weight status was only positively correlated with age. Moreover, a high prevalence of overweight (pre-obesity and obesity) and low physical activity was observed. Work-related issues were cited as the most common barrier to physical activity. Median scores were obtained for sleep health based on the scale used. It was also observed that firefighters who reported a tendency to eat more in stressful situations also had a tendency to consume more sweets, fast food, and fewer fruits and vegetables.
The results of our study highlight the need for larger-scale studies, emphasizing the possible need for the development of prevention and intervention programs targeted at firefighters, with the goal of improving their sleep health, preventing overweight and obesity, increasing levels of physical activity, and managing eating habits in stressful situations. These programs may be important in promoting the health and well-being of firefighters and contributing to the improvement of their quality of life.
Authors Contributions Statement
CO, MM, MS, SM and LO, conceptualization and study design; LO, data analysis; CO, MM, MS, SM, LO and CR, interpretation of results; CO, MM, MS, SM and LO, drafting, editing and reviewing; CO, MM, MS, SM and LO tables; LO, CR supervision and final writing.
This study was supported by the Fundação para a Ciência e a Tecnologia (FCT) through the CBIOS projects UIDB/04567/2020 and UIDP/04567/2020.
The authors would like to express their thanks to all participants.
Conflict of Interests
The authors declare there are no financial and/or personal relationships that could present a potential conflict of interests.
1. DGS. (2018). Promoção de um Estilo de Vida Saudável nos Bombeiros Portugueses. Lisboa: Ministério da Administração Interna., Autoridade Nacional de Proteção Civil., Direção Geral da Saúde.
2. Instituto Nacional de Estatística. (2022). Bombeiros (N.º) por Localização geográfica (NUTS - 2013), Sexo, Grupo etário e Tipo de vínculo; Anual. Disponível em: https://www.ine.pt/xportal/xmain?xpid=INE&xpgid=ine_indicadores&indOcorrCod=0007233&xlang=pt&contexto=bd&selTab=tab2
3. Ministério da Administração Interna. (2007). Decreto-Lei n.º 247/2007, de 27 de Junho. Diário da República n.º 122/2007, Série I de 2007-06-27.
4. Kaipust, C. M., Jahnke, S. A., Poston, W. S. C., Jitnarin, N., Haddock, C. K., Delclos, G. L., & Day, R. S. (2019). Sleep, Obesity, and Injury Among US Male Career Firefighters. Journal of Occupational and Environmental Medicine, 61(4), e150-e154. doi:10.1097/jom.0000000000001559
5. Brown, A. L., Wilkinson, M. L., Poston, W. S., Haddock, C. K., Jahnke, S. A., & Day, R. S. (2014). Adiposity predicts self-reported frequency of poor health days among male firefighters. Journal of Occupational and Environmental Medicine, 56(6), 667-672. doi:10.1097/jom.0000000000000163
6. Soteriades, E. S., Hauser, R., Kawachi, I., Christiani, D. C., & Kales, S. N. (2008). Obesity and risk of job disability in male firefighters. Occupational Medicine, 58(4), 245-250. doi:10.1093/occmed/kqm153
7. Soteriades, E. S., Hauser, R., Kawachi, I., Liarokapis, D., Christiani, D. C., & Kales, S. N. (2005). Obesity and cardiovascular disease risk factors in firefighters: a prospective cohort study. Obesity Research, 13(10), 1756-1763. doi:10.1038/oby.2005.214
8. Poston, W. S., Haddock, C. K., Jahnke, S. A., Jitnarin, N., Tuley, B. C., & Kales, S. N. (2011). The prevalence of overweight, obesity, and substandard fitness in a population-based firefighter cohort. Journal of Occupational and Environmental Medicine, 53(3), 266-273. doi:10.1097/JOM.0b013e31820af362
9. Rajabi, F., Molaeifar, H., Jahangiri, M., Taheri, S., Banaee, S., & Farhadi, P. (2020). Occupational stressors among firefighters: application of multi-criteria decision making (MCDM)Techniques. Heliyon, 6(4), e03820. doi:10.1016/j.heliyon.2020.e03820
10. Katsavouni, F., Bebetsos, E., Malliou, P., & Beneka, A. (2016). The relationship between burnout, PTSD symptoms and injuries in firefighters. Occupational Medicine, 66(1), 32-37. doi:10.1093/occmed/kqv144
11. Bonnell, E. K., Huggins, C. E., Huggins, C. T., McCaffrey, T. A., Palermo, C., & Bonham, M. P. (2017). Influences on Dietary Choices during Day versus Night Shift in Shift Workers: A Mixed Methods Study. Nutrients, 9(3). doi:10.3390/nu9030193
12. St-Onge, M. P., Crawford, A., & Aggarwal, B. (2018). Plant-based diets: Reducing cardiovascular risk by improving sleep quality? Current Sleep Medicine Reports, 4(1), 74-78.
13. St-Onge, M. P., Roberts, A., Shechter, A., & Choudhury, A. R. (2016). Fiber and Saturated Fat Are Associated with Sleep Arousals and Slow Wave Sleep. Journal of Clinical Sleep Medicine, 12(1), 19-24. doi:10.5664/jcsm.5384
14. Khosla, T., & Lowe, C. R. (1967). Indices of obesity derived from body weight and height. British Journal of Preventive and Social Medicine, 21(3), 122-128. doi:10.1136/jech.21.3.122
15. Weir, C. B., & Jan, A. (2022). BMI Classification Percentile And Cut Off Points. In StatPearls. Treasure Island (FL): StatPearls Publishing. Copyright © 2022, StatPearls Publishing LLC.
16. Martins, R. (2017). Validação da Escala de Saúde do Sono (SATED) para a população adulta portuguesa. (Mestre em Psicologia Clínica e da Saúde). Universidade do Algarve, Algarve, Portugal.
17. Buysse, D. J. (2014). Sleep health: can we define it? Does it matter? Sleep, 37(1), 9-17. doi:10.5665/sleep.3298
18. Craig, C. L., Marshall, A. L., Sjöström, M., Bauman, A. E., Booth, M. L., Ainsworth, B. E., Pratt, M., Ekelund, U., Yngve, A., Sallis, J. F., & Oja, P. (2003). International physical activity questionnaire: 12-country reliability and validity. Medicine & Science in Sports & Exercise, 35(8), 1381-1395. doi:10.1249/01.Mss.0000078924.61453.Fb
19. Association, W. M. (2013). World Medical Association Declaration of Helsinki: Ethical Principles for Medical Research Involving Human Subjects. JAMA, 310(20), 2191-2194. doi:10.1001/jama.2013.281053
20. Lopes, C., Torres, D., Oliveira, A., Severo, M., Alarcão, V., Guiomar, S., Mota, J., Teixeira, P., Rodrigues, S., Lobato, L., Magalhães, V., Correia, D., Carvalho, C., Pizarro, A., Marques, A., Vilela, S., Oliveira, L., Nicola, P., Soares, S. & Ramos, E. (2017). Inquérito Alimentar Nacional e de Atividade Física, IAN-AF 2015-2016: Relatório de resultados. Porto: Universidade do Porto.
21. Direção Nacional dos Bombeiros. (2021). Saúde e Seguranças dos Bombeiros - Relatório Final. Disponível em: https://prociv.gov.pt/media/eowhtbei/relat%C3%B3rio-sa%C3%BAde-e-seguran%C3%A7a-dos-bombeiros_29122021.pdf
22. Kling, H., Santiago, K., Benitez, L., Schaefer Solle, N., & Caban-Martinez, A. J. (2020). Characterizing Objective and Self-Reported Levels of Physical Activity Among Florida Firefighters Across Weight Status Category: A Cross-Sectional Pilot Study. Workplace Health & Safety, 68(11), 513-518. doi:10.1177/2165079920925505
23. Damacena, F. C., Batista, T. J., Ayres, L. R., Zandonade, E., & Sampaio, K. N. (2020). Obesity prevalence in Brazilian firefighters and the association of central obesity with personal, occupational and cardiovascular risk factors: a cross-sectional study. BMJ Open, 10(3), e032933. doi:10.1136/bmjopen-2019-032933
24. Savall, A., Charles, R., Trombert, B., Fontana, L., Roche, F., & Pelissier, C. (2021). Prevalence of cardiovascular risk factors in a population of French firefighters. Archives of Environmental & Occupational Health, 76(1), 45-51. doi:10.1080/19338244.2020.1779017
25. Chappel, S. E., Aisbett, B., Vincent, G. E., & Ridgers, N. D. (2016). Firefighters' Physical Activity across Multiple Shifts of Planned Burn Work. International Journal of Environmental Research and Public Health, 13(10). doi:10.3390/ijerph13100973
26. European Commission. (2022). Desporto e atividade física. Disponível em: https://www.portugalactivo.pt/sites/default/files/documentos_publicos/eurobarometro_portugal_-_desporto_e_atividade_fisica_2022.pdf
27. World Health Organization. (2020). WHO guidelines on physical activity and sedentary behaviour: at a glance. Geneva: World Health Organization.
28. Ras, J., Smith, D. L., Kengne, A. P., Soteriades, E. E., & Leach, L. (2022). Cardiovascular Disease Risk Factors, Musculoskeletal Health, Physical Fitness, and Occupational Performance in Firefighters: A Narrative Review. Journal of Environmental and Public Health, 2022, 7346408. doi:10.1155/2022/7346408
29. Sokoloski, M. L., Rigby, B. R., Bachik, C. R., Gordon, R. A., Rowland, I. F., Zumbro, E. L., & Duplanty, A. A. (2020). Changes in Health and Physical Fitness Parameters After Six Months of Group Exercise Training in Firefighters. Sports (Basel), 8(11). doi:10.3390/sports8110143
30. Soteriades, E. S., Vogazianos, P., Tozzi, F., Antoniades, A., Economidou, E. C., Psalta, L., & Spanoudis, G. (2022). Exercise and Occupational Stress among Firefighters. International Journal of Environmental Research and Public Health, 19(9). doi:10.3390/ijerph19094986
31. Lim, M., Jeong, K. S., Oh, S. S., Koh, S. B., Chang, S. J., & Ahn, Y. S. (2020). Effects of Occupational and Leisure-Time Physical Activities on Insomnia in Korean Firefighters. International Journal of Environmental Research and Public Health, 17(15). doi:10.3390/ijerph17155397
32. McGillis, Z., Dorman, S. C., Robertson, A., Larivière, M., Leduc, C., Eger, T., Oddson, B. E., & Larivière, C. (2017). Sleep Quantity and Quality of Ontario Wildland Firefighters Across a Low-Hazard Fire Season. Journal of Occupational and Environmental Medicine, 59(12), 1188-1196. doi:10.1097/jom.0000000000001175
33. Lim, M., Lee, S., Seo, K., Oh, H. J., Shin, J. S., Kim, S. K., Kang, H. T., Jeong, K. S., Oh, S. S., Koh, S. B. & Ahn, Y. S. (2020). Psychosocial factors affecting sleep quality of pre-employed firefighters: a cross-sectional study. Annals of Occupational and Environmental Medicine, 32, e12. doi:10.35371/aoem.2020.32.e12
34. Jeong, K. S., Ahn, Y. S., Jang, T. W., Lim, G., Kim, H. D., Cho, S. W., & Sim, C. S. (2019). Sleep Assessment During Shift Work in Korean Firefighters: A Cross-Sectional Study. Safety and Health at Work, 10(3), 254-259. doi:10.1016/j.shaw.2019.05.003
35. Stout, J. W., Beidel, D. C., Brush, D., & Bowers, C. (2021). Sleep disturbance and cognitive functioning among firefighters. Journal of Health Psychology, 26(12), 2248-2259. doi:10.1177/1359105320909861
36. Khumtong, C., & Taneepanichskul, N. (2019). Posttraumatic stress disorder and sleep quality among urban firefighters in Thailand. Nature and Science of Sleep, 11, 123-130. doi:10.2147/nss.S207764
37. Zellner, D. A., Loaiza, S., Gonzalez, Z., Pita, J., Morales, J., Pecora, D., & Wolf, A. (2006). Food selection changes under stress. Physiology & Behavior, 87(4), 789-793. doi:10.1016/j.physbeh.2006.01.014
38. Leow, S., Beer, N. J., Guelfi, K. J., Rebar, A. L., Alderson, J. A., Jackson, B., & Dimmock, J. A. (2021). Perceived daily tension and food cravings and consumption: A within- and between-person investigation. Eating Behaviors, 40, 101473. doi:10.1016/j.eatbeh.2020.101473
39. Rodrigues, S., Paiva, J. S., Dias, D., & Cunha, J. P. S. (2018). Stress among on-duty firefighters: an ambulatory assessment study. PeerJ, 6, e5967. doi:10.7717/peerj.5967
40. Hsiao, H., Weaver, D., Hsiao, J., Whitestone, J., Kau, T. Y., Whisler, R., & Ferri, R. (2014). Comparison of measured and self-reported anthropometric information among firefighters: implications and applications. Ergonomics, 57(12), 1886-1897. doi:10.1080/00140139.2014.952351.