Effect of Exercise Intensity and Thermal Strain on Wildland Firefighters' Central Nervous System Fatigue

  1. A Rodríguez-Marroyo, Jose 1
  2. Carballo Leyenda, Belén 1
  3. Sánchez Collado, Pilar 1
  4. Suárez Iglesias, David 1
  5. G Villa, José 1
  1. 1 Universidad de León
    info
    Universidad de León

    León, España

    ROR https://ror.org/02tzt0b78

    Geographic location of the organization Universidad de León
Proceedings:
Cognitive Computing and Internet of Things

ISSN: 2771-0718

Year of publication: 2022

Pages: 58-63

Type: Conference paper

DOI: 10.54941/AHFE1001839 SCOPUS: 2-s2.0-105036367625 GOOGLE SCHOLAR

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Abstract

The arduous conditions (i.e., harsh environmental conditions, high physical and mental demands) in which wildland firefighters (WFFs) have to perform their work during wildfire suppression can lead to physical and mental fatigue. Although several studies have delved into the first type of fatigue, there is a paucity of research on decreased WFFs’ cognitive performance. A decreased cognitive performance has been observed throughout multiday suppression tasks, leading to poor decision-making and uninten-ded deployment consequences. To our knowledge, the acute effect of tasks performed by WFFs on cognitive fatigue has not been studied. Therefore, the aim of this study was to analyze the effect of performing a specific circuit, which simulated the tasks performed by WFFs in their deployments, on central nervous system fatigue. Ten WFFs (34.4 ± 5.6 yr, 182.9 ± 6.1 cm, and 92.8 ± 14.9 kg) participated in the study, who performed a field test composed of 4 specific tasks commonly used in their deployments. Each task was executed for 5 min interspersed by 90 s of recovery. This interval bout was repeated twice with 10 min of recovery in between. Heart rate (HR) and core temperature (CT) response were monitored during the test. Both variables were used to calculate the physiological strain index (PSI). In addition, before and at the end of the field test, subjects’ critical flicker fusion (CFF) threshold was measured. The results showed that the WFFs performed a high-exercise demand (mean HR, 85.3 ± 2.5% of maximal HR; CT, 38.3 ± 0.4 °C and PSI, 6.0 ± 0.7). Despite this, CFF threshold measure-ments showed an increase (6.0 ± 6.0%, p < 0.05) in the sensory sensitivity threshold, suggesting an exercise-induced increase in cortical arousal. Significant (p < 0.05) relationships between sensory sensitivity and time spent at high percentage of maximal HR (>90%), TC and PSI were found (r = −0.71, −0.74 and-0.69, respectively). In conclusion, the specific field test enhanced sensory sensitivity and cortical arousal. However, the correlations found seem to indicate the potential negative effect of high-intensity exercise and thermal strain on central nervous system fatigue.

Bibliographic References

  • Carballo-Leyenda, B., Gutiérrez-Arroyo, J., García-Heras, F., Sánchez-Collado, P., Villa-Vicente, J.G. and Rodríguez-Marroyo, J.A. (2021) “Inf luence of Personal Protective Equipment on Wildland Firefighters’ Physiological Response and Performance during the Pack Test”, International Journal of Environmental Research and Public Health, 18(10), 5050.
  • Carballo-Leyenda, B., Villa, J.G., López-Satué, J., Collado, P.S. and Rodríguez-Marroyo, J.A. (2018) “Fractional contribution of wildland firefighters’ personal protective equipment on physiological strain”, Frontiers in Physiology, 9, 1139.
  • Davranche, K. and Audiffren, M. (2004) “Facilitating effects of exercise on information processing”, Journal of Sports Sciences, 22(5), 419–428.
  • Edwards, S. (1993) “High performance training and racing”, in Edwards, S. (ed.) The Heart Rate Monitor Book. Sacramento: Feet Fleet Press, pp. 113–123.
  • Jacklitsch, B., Williams, W.J., Musolin, K., Coca, A., Kim, J-H. and Turner, N. (2016) “NIOSH criteria for a recommended standard: occupational exposure to heat and hot environments” Cincinnati, OH: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication 2016–106.
  • Jeklin, A.T., Davies, H.W., Bredin, S.S.D, Hives, B.A, Meanwell, L.E, Perrotta, A.S. and Warburton, D.E.R. (2020) “Fatigue and sleep patterns among Canadian wild-land firefighters during a 17-day fire line deployment”, Journal of Occupational and Environmental Hygiene, 17(7-8), 364–371.
  • Morley, J., Beauchamp, G., Suyama, J., Guyette, F.X., Reis, S.E., Callaway, C.W., et al. (2012) “Cognitive function following treadmill exercise in thermal protective clothing”, European Journal of Applied Physiology, 112(5), 1733–1740.
  • Rodríguez-Marroyo, J.A., López-Satue, J., Pernía, R., Carballo, B., García-López, J., Foster, C. and Villa, J.G. (2012) “Physiological work demands of Spanish wildland firefighters during wildfire suppression”, International Archives of Occupational and Environmental Health, 85(2), 221–228.
  • Ruby, B.C., Shriver, T.C., Zderic, T.W., Sharkey, B.J., Burks, C. and Tysk, S. (2002) “Total energy expenditure during arduous wildfire suppression”, Medicine and Science in Sports and Exercise, 34(6), 1048–1054.
  • Tanaka, H., Monahan, K.D. and Seals, D.R. (2001). “Age-predicted maximal heart rate revisited”, Journal of American College of Cardiology, 37(1), 153–156.
  • Tomporowski, P.D. (2003) “Effects of acute bouts of exercise on cognition”, Acta Psychologica, 112(3), 297–324.
  • Vincent, G.E., Aisbett, B., Hall, S.J and Ferguson, S.A. (2016) “Fighting fire and fatigue: sleep quantity and quality during multi-day wildfire suppression”, Ergonomics, 59(7), 932–940.
  • Wen, S., Petersen, S., McQueen, R. and Batcheller, J. (2015) “Modelling the physiological strain and physical burden of chemical protective coveralls”, Ergonomics, 58(12), 2016–2031.
  • Williams-Bell, F.M., Aisbett, B., Murphy, B.A. and Larsen, B. (2017) “The Effects of Simulated Wildland Firefighting Tasks on Core Temperature and Cognitive Function under Very Hot Conditions”, Frontiers in Physiology, 8, 815.
  • Williamson, A., Lombardi, D.A., Folkard, S., Stutts, J., Courtney, T.K. and Con-nor, J.L. (2011) “The link between fatigue and safety”, Accident Analysis and Prevention, 43(2), 498–515.