Citation

Smith G, Bishop P, Beaird J, Ray P, Smith JL. Int. J. Ind. Ergonomics 1994; 13(2): 147-155.

Copyright

(Copyright © 1994, Elsevier Publishing)

DOI

unavailable

PMID

unavailable

Abstract

Work tolerance in protective clothing (PC) is greatly limited compared to normal clothing. The purpose of this study was to determine if this limitation is attributable to any readily identifiable aspect of physiology. Male volunteers (N = 15) completed an average of 263 min of endurance exercise at a metabolic cost of 40-44% of maximal oxygen uptake (VO2 max) which consisted of repeated bouts of 15 min treadmill walking followed by 5 min of arm curls. Subjects continued to walk-arm curls to exhaustion. For safety reasons, they were also stopped if their rectal temperature (Tre) exceeded 39[deg]C. The termination of work by either of these criteria ended a work "cycle". On completion of a cycle, subjects rested 48 min then resumed exercise. The exercise day ended when the subject refused to continue or experiment time equaled 8 h. All 15 subjects completed two work cycles and 8 completed three cycles. Work ended on 28 work cycles due to fatigue and on 10 cycles due to Tre. Heart rate (HR), rating of perceived exertion, maximal voluntary ventilation, thermal comfort, oxygen uptake (VO2), blood lactic acid levels, and 3 measures of breathing comfort were measured throughout testing. Significant changes across time were seen only in HR and the subject's perceptions of the stressors but, HR increases were insufficient to explain the termination of work. Work tolerance in this situation apparently cannot be extended by resolving any simple physiological limitations.