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Work patterns dictate energy demands and thermal strain during wildland firefighting.
Wilderness Environ Med 2015; 26(2):221-6WE

Abstract

OBJECTIVE

The purpose of this investigation was to characterize the effects of self-selected work activity on energy expenditure, water turnover, and thermal strain during wildland fire suppression. A secondary aim was to contrast current data with data collected 15 years ago using similar methods to determine whether job demands have changed.

METHODS

Participants (n=15, 26±3 years, 179±6 cm, 78.3±8.6 kg) were monitored for 3 days for total energy expenditure, water turnover, core and chest skin temperature, physical activity, and heart rate. Participants arrived to the mobile laboratory each morning, submitted a nude weight, ingested a temperature transmitter, provided a urine sample, and were equipped with a physiological and activity monitor. Participants completed live wildland fire suppression during their work shifts.

RESULTS

Mean core temperature was 37.6°±0.2°C, mean chest skin temperature was 34.1°±1.0°C, mean heart rate was 112±13 beats/min, and the mean physiological strain index score was 3.3±1.0. Wildland firefighters spent 49±8%, 39±6%, and 12±2% in the sedentary, light, and moderate-vigorous intensity categories, respectively. The mean total energy expenditure was 19.1±3.9 MJ/d, similar to 1997 (17.5±6.9 MJ/d). The mean water turnover in 2012 was 9.5±1.7 L/d, which was higher (P<.05) compared with 1997-98 (7.0±1.7 L/d).

CONCLUSIONS

Wildland firefighters do not induce consistently high cardiovascular and thermal strain while completing arduous work in a hot environment despite fairly high chest skin temperatures. The total energy expenditure in the current study suggests job demands are similar to those of 15 years ago, while the increased water turnover may reflect a change in drinking habits.

Authors+Show Affiliations

Montana Center for Work Physiology and Exercise Metabolism, The University of Montana, Missoula, MT.Montana Center for Work Physiology and Exercise Metabolism, The University of Montana, Missoula, MT.Montana Center for Work Physiology and Exercise Metabolism, The University of Montana, Missoula, MT.Montana Center for Work Physiology and Exercise Metabolism, The University of Montana, Missoula, MT. Electronic address: brent.ruby@mso.umt.edu.

Pub Type(s)

Journal Article
Research Support, U.S. Gov't, Non-P.H.S.

Language

eng

PubMed ID

25772825

Citation

Cuddy, John S., et al. "Work Patterns Dictate Energy Demands and Thermal Strain During Wildland Firefighting." Wilderness & Environmental Medicine, vol. 26, no. 2, 2015, pp. 221-6.
Cuddy JS, Sol JA, Hailes WS, et al. Work patterns dictate energy demands and thermal strain during wildland firefighting. Wilderness Environ Med. 2015;26(2):221-6.
Cuddy, J. S., Sol, J. A., Hailes, W. S., & Ruby, B. C. (2015). Work patterns dictate energy demands and thermal strain during wildland firefighting. Wilderness & Environmental Medicine, 26(2), pp. 221-6. doi:10.1016/j.wem.2014.12.010.
Cuddy JS, et al. Work Patterns Dictate Energy Demands and Thermal Strain During Wildland Firefighting. Wilderness Environ Med. 2015;26(2):221-6. PubMed PMID: 25772825.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Work patterns dictate energy demands and thermal strain during wildland firefighting. AU - Cuddy,John S, AU - Sol,Joseph A, AU - Hailes,Walter S, AU - Ruby,Brent C, Y1 - 2015/03/12/ PY - 2014/02/18/received PY - 2014/12/05/revised PY - 2014/12/13/accepted PY - 2015/3/17/entrez PY - 2015/3/17/pubmed PY - 2015/12/22/medline KW - core temperature KW - field study KW - occupational physiology KW - skin temperature SP - 221 EP - 6 JF - Wilderness & environmental medicine JO - Wilderness Environ Med VL - 26 IS - 2 N2 - OBJECTIVE: The purpose of this investigation was to characterize the effects of self-selected work activity on energy expenditure, water turnover, and thermal strain during wildland fire suppression. A secondary aim was to contrast current data with data collected 15 years ago using similar methods to determine whether job demands have changed. METHODS: Participants (n=15, 26±3 years, 179±6 cm, 78.3±8.6 kg) were monitored for 3 days for total energy expenditure, water turnover, core and chest skin temperature, physical activity, and heart rate. Participants arrived to the mobile laboratory each morning, submitted a nude weight, ingested a temperature transmitter, provided a urine sample, and were equipped with a physiological and activity monitor. Participants completed live wildland fire suppression during their work shifts. RESULTS: Mean core temperature was 37.6°±0.2°C, mean chest skin temperature was 34.1°±1.0°C, mean heart rate was 112±13 beats/min, and the mean physiological strain index score was 3.3±1.0. Wildland firefighters spent 49±8%, 39±6%, and 12±2% in the sedentary, light, and moderate-vigorous intensity categories, respectively. The mean total energy expenditure was 19.1±3.9 MJ/d, similar to 1997 (17.5±6.9 MJ/d). The mean water turnover in 2012 was 9.5±1.7 L/d, which was higher (P<.05) compared with 1997-98 (7.0±1.7 L/d). CONCLUSIONS: Wildland firefighters do not induce consistently high cardiovascular and thermal strain while completing arduous work in a hot environment despite fairly high chest skin temperatures. The total energy expenditure in the current study suggests job demands are similar to those of 15 years ago, while the increased water turnover may reflect a change in drinking habits. SN - 1545-1534 UR - https://www.unboundmedicine.com/medline/citation/25772825/Work_patterns_dictate_energy_demands_and_thermal_strain_during_wildland_firefighting_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S1080-6032(14)00429-3 DB - PRIME DP - Unbound Medicine ER -