Research Study Abstract

Accelerometer-based physical activity and sedentary behavior assessment in Brazilian military firefighters: the Brasilia Firefighters Study – BFS

  • Presented on Oct. 2017

Introduction: Firefighting is known to be a high cardiovascular risky activity, involving elevated physical and psychological demands. We hypothesized that during a routine 24-hour on-duty period firefighters combine physical activities of different intensities/durations with long periods of sedentary behavior.

Purpose: To evaluate the physical activity level (PAL) and sedentary behavior (SB) of military firefighters during a 24-hour on-duty period and the subsequent 72-hour off-duty period.

Methods: We conducted a cross-sectional study with a convenience sample of military firefighters from the Brasilia Fire Department (CBMDF). Twelve men with mean age of 37±6.7 years, BMI of 25.3±3.8 kg/m² and VO2max 43,52±4,52 mL(kg.min)-1 participated. The volunteers used an accelerometer (ActiGraph GT3X+) set in 60s epochs, positioned in the right side (waist) for a period of 4 days (24/72h), with a minimum of 10h/day of valid wear-time. The PAL and SB were compared between working day and the mean of the subsequent 3-day off-duty period considering: CS <100 counts per minute (cpm), light activity between 100 and 1951 cpm, moderate between 1952 and 5724 cpm, vigorous between 5725 and 9498 cpm and very vigorous >9499 cpm (Freedson 1998). VO2max was estimated by the formula proposed by Jackson et al. (1990). Median (extreme) absolute and relative values corresponding to the work day and the 3 off-duty days were calculated. Wilcoxon test at a significance level of 5% was used for comparisons.

Results: The mean time of daily use of the accelerometer was 18h:10min on the on-duty day and 17h:11min during the off-duty period (p > 0.05). The recommendation of 30 min of moderate to vigorous physical activity (MVPA) was achieved on 95,8% of the 48 monitored days. Length of stay in SB and in all physical activity intensity zones, in addition to daily steps are expressed in Table 1.

[Table omitted for compatibility reasons]

Conclusion: A high proportion of compliance with the 30 minutes of MVPA per day recommendation was observed in both on-duty and off-duty periods. It was also observed a high SB time (aprox. 50% of the day) either on the on-duty and the off-duty days as well as a longer time of vigorous activity during the working day as compared to the 3-day off-duty period. The data are in accordance with our hypothesis, however a larger sample is needed to confirm these findings.


  • Daniel Saint Martin 1
  • Leonardo Correa Segedi 1,2
  • Keila Elisabeth Fontana 1
  • Edgard M. K. Von Koenig Soares 1
  • Guilherme E. Molina 1
  • Rosenkranz Maciel Nogueira 1,2
  • Luiz Guilherme Grossi Porto 1


  • 1

    Faculdade de Educação Física da Universidade de Brasília - FEF - UnB e Grupo de Estudos em Fisiologia e Epidemiologia do Exercício e da Atividade Física (GEAFS)

  • 2

    Corpo de Bombeiros Militar do Distrito Federal - CBMDF

Presented at

CELAFISCS 2017 International Symposium of Sports Science


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