The effect of physical exertion in chemical and biological personal protective equipment on physiological function and reaction time.

摘要

OBJECTIVES: The primary objective of this study was to describe and compare changes in heart rate, venous pH, venous partial pressure of carbon dioxide (pCO(2)), venous bicarbonate level, lactate level, oxygen saturation (SpO(2)), and tympanic membrane (TM) temperature occurring in a group of healthy volunteers during 20 minutes of physical exertion, both with and without chemical and biological personal protective equipment (PPE). A further aim was to establish whether any significant prolongation of reaction time occurred after physical exertion in chemical and biological PPE, compared to baseline values without the protective equipment. METHODS: Nineteen highly fit volunteers were subjected to a baseline reaction time test and measurement of physiological variables. They were then subjected to physical exertion on a treadmill: once while wearing a short-sleeved t-shirt, shorts, and running shoes and once while wearing chemical and biological PPE. Repeat measurements of the physiological variables were made after 10 and 20 minutes of physical exertion in both groups, after which repeat reaction time tests were conducted. RESULTS: Results showed that physical exertion of 20 minutes undertaken by highly fit volunteers wearing PPE resulted in a higher heart rate response and TM temperature compared with control measurements. Decreased venous pH and increased venous pCO(2) were also observed during exertion in the PPE group. Although differences in these variables between the control and PPE groups were statistically significant, they were not of clinical relevance in the sample of volunteers studied. No significant difference in reaction time before and after exertion in PPE was identified. CONCLUSIONS: This study did not identify any effect of 20 minutes of heavy exercise in highly fit volunteers wearing level C chemical and biological PPE on reaction time. Heart rate response and TM temperature were higher during exertion in PPE. These differences, along with other physiological alterations observed, were not of clinical relevance. Further studies using arterial blood gas analysis and a more accurate measure of core body temperature are needed to better assess the physiological effect of this level and duration of exercise on subjects wearing similar PPE. Other aspects of cognition also require investigation under these conditions, in order to assess their effect on patient and rescuer safety.