Loss of performance while wearing a respirator does not increase during a 22.5-hour wearing period

To measure loss of performance while wearing a military respirator with and without chemical warfare (CW) clothing for an extended time, a field experiment was carried out with 24 military subjects. With only few short breaks the respirator was worn for 22 h and 30 min, including sleep. Several tests were repeated at different intervals: a 3-km field track run, an obstacle course, and a memory and concentration task. At the field track run the respirator caused 18-20% loss of performance. On the average there was 9% loss of performance at the obstacle course. The memory and concentration task showed 12% loss of performance, however, this only concerned non-mental aspects, such as constriction of visual field. The CW-garment itself led to less loss of performance than the respirator and if both were worn simultaneously, hindrance by the garment was not at all apparent. None of the tests showed an increase in loss of performance with the accumulation of wearing time.