Aerobic Capacity and Maximal Work Performance in Firefighters: The Role of Age and Body Composition in Occupational Health Risk

Authors

Payton E. Miller, Texas Tech UniversityFollow
Michael Conner, Bond UniversityFollow
Grant M. Tinsley, Texas Tech UniversityFollow
Drew E. Gonzalez, Sam Houston State UniversityFollow
Christine M. Florez, Texas Tech UniversityFollow
Carina M. Velasquez, Texas Tech UniversityFollow
Kelly HinesFollow
Jacob A. Mota, Texas Tech UniversityFollow

Abstract

Firefighting requires repeated bouts of high-intensity physical work performed under extreme environmental conditions, placing substantial strain on the cardiovascular and musculoskeletal systems. Cardiovascular disease (CVD) remains the leading cause of on-duty firefighter fatalities, with the majority of deaths occurring among firefighters aged 40 years and older. Physiological characteristics such as age and body composition influence aerobic capacity and maximal work performance, both of which are critical and essential while performing strenuous operations. PURPOSE: The purpose of this study was to examine how age, sex, and body composition affect aerobic capacity (VO_2peak) and maximal work capacity (W_max) in career firefighters. METHODS: Retrospective data from of 3,840 career firefighters (3,630 males; age 39 ± 11 years, BMI = 29.7 ± 4.5 kg·m^-2; 210 females; age 35 ± 11 years, BMI = 26.3 ± 4.0 kg·m^-2) were analyzed. Body composition, including body fat percentage (BF%) and fat-free mass index (FFMI), was assessed using bioelectrical impedance. VO_2peak and W_max were measured during a graded cycle ergometry test. Associations of age, sex, BF%, and FFMI with VO_2peak and W_max were evaluated using ordinary least squares, with significance set at p < 0.05. RESULTS: Male firefighters demonstrated greater FFMI (22.2 ± 2.0 vs. 18.3 ± 1.6 5 kg·m^-2) and higher W_max (261.0 ± 43.8 vs. 197.8 ± 39.0 W), whereas female firefighters exhibited higher BF% (29.5 ± 7.9 vs. 24.2 ± 7.9%). VO_2peak expressed relative to body mass and VO_2FFM relative to fat-free mass was comparable between sexes (32.8 ± 6.6 vs. 31.5 ± 6.3 ml/kg/min; 44.5 ± 6.4 vs. 43.1 ± 6.4 ml/kg FFM/min, respectively). Regression analyses indicated that increasing age and BF% were associated with lower VO_2peak (-0.17 ml/kg/min per year; -0.50 ml/kg/min per 1% BF), with an adjusted R² of 0.53. VO_2FFM was also negatively associated with age and BF% and slightly lower in males, with an adjusted R² of 0.17. Both age and BF% were inversely associated with W_max, whereas higher FFMI predicted greater maximal work output, with an adjusted R² of 0.42. CONCLUSION: These findings emphasize the importance of maintaining optimal body composition to support cardiovascular health and reduce occupational injury risk; highlight modifiable physiological factors that could mitigate on-duty CVD related fatalities. Understanding these physiological relationships can guide training and conditioning strategies to enhance readiness, mitigate CVD risk, and improve long-term health outcomes in the fire service.

Recommended Citation

Miller, Payton E.; Conner, Michael; Tinsley, Grant M.; Gonzalez, Drew E.; Florez, Christine M.; Velasquez, Carina M.; Hines, Kelly; and Mota, Jacob A. (2026) "Aerobic Capacity and Maximal Work Performance in Firefighters: The Role of Age and Body Composition in Occupational Health Risk," International Journal of Exercise Science: Conference Proceedings: Vol. 2: Iss. 18, Article 209.
Available at: https://digitalcommons.wku.edu/ijesab/vol2/iss18/209