Abstract
Protective vests worn by global security personnel, and weighted vests worn by athletes, may increase physiological strain due to added load, increased clothing insulation and vapor resistance. The impact of protective vest clothing properties on physiological strain, and the potential of a spacer garment to reduce physiological strain, was examined. Eleven men performed 3 trials of intermittent treadmill walking over 4 h in a hot, dry environment (35°C, 30% rh). Volunteers wore the US Army battledress uniform (trial B), B + protective vest (trial P), and B + P + spacer garment (trial S). Biophysical clothing properties were determined and found similar to many law enforcement, industry, and sports ensembles. Physiological measurements included core (T c), mean skin (T sk) and chest (T chest) temperatures, heart rate (HR), and sweating rate (SR). The independent impact of clothing was determined by equating metabolic rate in all trials. In trial P, HR was +7 b/min higher after 1 h of exercise and +19 b/min by the fourth hour compared to B (P < 0.05). T c (+0.30°C), T sk (+1.0°C) and Physiological Strain Index were all higher in P than B (P < 0.05). S did not abate these effects except to reduce T sk (P > S) via a lower T chest (−0.40°C) (P < 0.05). SR was higher (P < 0.05) in P and S versus B, but the magnitude of differences was small. A protective vest increases physiological strain independent of added load, while a spacer garment does not alter this outcome.
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Acknowledgments
The authors wish to thank Rob Coleman and Rick Gallimore for providing the Interceptor Body Armor and spacer vests used in this study, respectively. We also thank the Biophysics and Modeling Division for manikin clothing data, Josh Bulotsky (Doriot Chamber facility), the entire Thermal and Mountain Medicine Division technical support staff, and most importantly the soldiers who volunteered their time to take part in this study. The view, opinions, and/or findings contained in this report are those of the authors and should not be construed as an official Department of the Army position, or decision, unless so designated by other official documentation. Approved for public release; distribution unlimited.
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Cheuvront, S.N., Goodman, D.A., Kenefick, R.W. et al. Impact of a protective vest and spacer garment on exercise-heat strain. Eur J Appl Physiol 102, 577–583 (2008). https://doi.org/10.1007/s00421-007-0632-3
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DOI: https://doi.org/10.1007/s00421-007-0632-3