Cognitive performance was studied in six male and three female subjects exposed to two randomly administered 10-hour measurement periods, a control condition without a respirator and a respirator wear trial requiring continuous wear, under nonexercise conditions. Reaction time and decision-making speed were assessed using a series of simple and choice reaction time tasks at the start of each test iteration and after hours 2, 4, 6, 8, and 10 of testing. Subject anxiety levels were assessed along with reaction time measures. Visual tracking ability was measured after each hour of testing. Reaction time and decision-making speed did not differ significantly between control and respirator conditions at any time throughout the 10 hours of testing. Female volunteers exhibited significantly faster reaction times and decision-making speeds than males independent of respirator wear conditions and time of measurement. Subject anxiety increased significantly from initial measurements after 8 hours of testing for each condition, but no differences were observed between conditions at any time. Respirator wear did not detrimentally influence visual tracking ability. These findings suggest that respirator wear over a relatively long time period under nonexercise conditions should not significantly inhibit cognitive function.