title: Physiological work demands of Spanish wildland firefighters during wildfire suppression.
abstract: OBJECTIVE
  The aim of this study was to analyze the physiological demands and thermal strain of wildland firefighters during real wildfire suppression.
  
  
  METHODS
  The response of core temperature and heart rate (HR) were analyzed in 200 wildland firefighters during wildfire suppression activities of different duration: <1 h (n = 52), 1-3 h (n = 70), 3-5 h (n = 44), and >5 h (n = 34). The exercise workload (TRIMP), the physiological strain index (PSI), and cumulative heat strain index (CHSI) were calculated using the time spent in different intensity zones, the HR, and core temperature.
  
  
  RESULTS
  Mean HR was significantly higher (P < 0.05) in wildfires <1 h (133 ± 2 bpm) and 1-3 h (128 ± 1 bpm) versus 3-5 h (120 ± 3 bpm) and >5 h (116 ± 32 bpm). The time spent in higher intensity zones increased (P < 0.05) when wildfire duration increased. TRIMP accumulation increased with wildfire duration (54.9 ± 3.2, 167.4 ± 5.9, 296.0 ± 8.3, 511.7 ± 12.8 in <1, 1-3, 3-5, and >5 h, respectively). Neither core temperature (37.4 ± 0.1°C) nor PSI (4.5 ± 0.2) were influenced by wildfire duration. The CHSI increased (p < 0.05) in the following order: <1 h (104 ± 23), 1-3 h (1,396 ± 275), 3-5 h (4,586 ± 387), and >5 h (10,703 ± 710).
  
  
  CONCLUSIONS
  The results demonstrate the high work strain sustained by Spanish wildland firefighters during wildfire suppression. Both workload and CHSI increased with the wildfires duration although the pace of work was faster in wildfires of a shorter duration.
authors.affiliation: Department of Physical Education and Sports, Institute of Biomedicine (IBIOMED), University of León, 24071, León, Spain. j.marroyo@unileon.es
authors.forename: Jose A
authors.initials: JA
authors.lastname: Rodríguez-Marroyo
authors.forename: Jorge
authors.initials: J
authors.lastname: López-Satue
authors.forename: Raul
authors.initials: R
authors.lastname: Pernía
authors.forename: Belén
authors.initials: B
authors.lastname: Carballo
authors.forename: Juan
authors.initials: J
authors.lastname: García-López
authors.forename: Carl
authors.initials: C
authors.lastname: Foster
authors.forename: José G
authors.initials: JG
authors.lastname: Villa
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001831:Body Temperature; D005390:Fires; D006339:Heart Rate; D006358:Hot Temperature; D006801:Humans; D016273:Occupational Exposure; D005082:Physical Exertion; D013030:Spain; D018709:Statistics, Nonparametric; D013312:Stress, Physiological / Q000502:physiology*; D013997:Time Factors; D016526:Workload