Physiologic Effects of Simulated Firefighting Tasks Compared with Continuous Exercise, in Heat and PPE

Details

• Personal Author:
  Armstrong L ; Bogucki, Sandy ; Burns KJ ; Pranger LA ; Van Gelder CM ; Wiesmann WP ; Armstrong L ; Bogucki, Sandy ; Burns KJ ; Pranger LA ; Van Gelder CM ; Wiesmann WP
• Description:
  Objectives: This study compared the physiologic responses of firefighters (FFs) performing simulated fireground tasks with those of FFs performing continuous exercise to volitional fatigue. Previous studies by our group established the validity of both experimental models of uncompensable heat stress in FFs, but did not directly compare them. Methods: 13 FFs (12 male, 1 female) wearing standard firefighting personal protective ensemble (PPE) and Self-contained breathing apparatus (SCBA) in a heated environment (40 degrees C) completed both protocols. In the first phase, subjects completed tasks simulating fire suppression, including treadmill walking while carrying a hose, ladder climbing, simulated search and rescue, and a pike pole breach-and-pull exercise. The second phase consisted of walking on a treadmill while wearing a weighted vest at a 4-mph rate and a 2% grade. In both phases, subjects exercised to volitional fatigue. Physiologic markers measured or calculated included hemoglobin, hematocrit, glucose, lactate, urine and plasma osmolality, plasma volume, body weight, body mass index (BMI), core temperature, heat storage, and maximum volume of oxygen consumption (VO2max). Duration of exercise was recorded and FFs gave serial ratings of perceived exertion. Results: Durations of exercise ranged from 4 to 22 minutes, were not significantly different between the two phases, and positively correlated with heat storage and lactate levels. Simulated fire tasks caused greater increases in lactate (mean 8.8mmol/L), plasma osmolality levels (mean 296mOsm/kg), plasma volume loss (mean 12%), core temperature (>39 degrees C), and higher heat storage levels (mean 339 kJ) than did weighted treadmill testing. Subjects in phase two did not have significant changes in these variables, despite working to volitional fatigue. Those with a lower BMI tended to have a higher VO2max, but BMI had no correlation with duration of exercise. Conclusions: We have demonstrated that firefighters in a hot environment and wearing PPE are significantly more physiologically stressed by simulated fireground tasks than by continuous aerobic exercise, despite similar durations of exercise and ratings of perceived exertion. This physiologic stress and its lack of correlation with volitional fatigue may contribute to line-of-duty illness and injury to FFs, and may have implications for management of fireground illness and injuries. [Description provided by NIOSH]
• Subjects:
  Energy Metabolism Fatigue Firefighters Fires Heat Stress Disorders Hot Temperature Occupational Health Personal Protective Equipment Safety
• Keywords:
  Fire Fighters Fire Safety Heat Exposure Heat Stress Hot Environments Metabolic Effects Personal Protective Equipment Physiological Stress PPE Weight Factors
• ISSN:
  1090-3127
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Abstract or Summary ; Abstract or Summary
• Place as Subject:
  Connecticut ; Maryland ; OSHA Region 1 ; OSHA Region 3
• CIO:
  National Institute for Occupational Safety and Health (NIOSH) ; National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health ; Workplace Safety & Health
• Location:
  North America ; North America
• Pages in Document:
  108-109
• Volume:
  10
• Issue:
  1
• NIOSHTIC Number:
  nn:20052267
• Citation:
  Prehosp Emerg Care 2006 Jan-Mar; 10(1):108-109
• Federal Fiscal Year:
  2006
• Performing Organization:
  Sekos, Inc., Germantown, Maryland
• Peer Reviewed:
  True
• Start Date:
  20000930
• Source Full Name:
  Prehospital Emergency Care
• End Date:
  20070930
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:787cb369b9a21ecfb8f24bc3b8827d4e38eb3d91019b5e84cb05ae1923568d0deb3fddd00907f2b0551fe91926314a1242d1bb986b9298caf2313c4b26aaadfc
• Download URL:
  https://stacks.cdc.gov/view/cdc/211821/cdc_211821_DS1.pdf
• File Type:
  [PDF - 111.21 KB ]