Respiratory Resistance and the Endurance of Men Working under Thermal Stress.
Technical rept. Dec 73-Jul 74,
EDGEWOOD ARSENAL ABERDEEN PROVING GROUND MD
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The effect of the respiratory resistances of the M17A1 protective mask on endurance in hard work of five men wearing the two-layer permeable protective assembly was tested by comparing the standard mask with one whose inspiratory and expiratory resistances were 3 mm H2O at an airflow of 85 liters per minute. Four comparisons were made at 18C, nine at 41C, and three at 46C in walking at 3 mph or jogging at 4 mph, both up a 10 percent grade. The 3-mph walks represented a workload of from one-third to one-half the measured maximal oxygen uptake. The physiological state at exhaustion was examined in terms of the heart rate, rectal temperature, and the time devoted to the expiratory phase of the respiratory cycle. For men walking at 3 mph up a 10 percent grade, the heat load of the permeable protective assembly restricts endurance at environmental temperatures of 18C and above. The respiratory stress of the M17A1 protective mask does not add significantly to the restriction on endurance under these conditions.
- Stress Physiology
- Human Factors Engineering and Man Machine Systems
- Protective Equipment