Performance, Heart Rate, and Respiration Rate on the Day-Night Continuum

Abstract

Each of 15 female college students was tested at 4 P.M., 10 P.M., 4 A.M., and 10 A.M. Pulse rate and respiration rate were gauged directly before task performance. An RT task was followed by time estimation. Pulse and respiration rates were slowest at 4 A.M. and increased significantly by the 10 A.M. testing, followed by a gradual decline. Both RT and time estimation were poorest at 4 A.M., reached a peak at 10 A.M. and gradually declined. These findings agree with previous data which show that, as activation level increases up to a certain point, performance improves. No Ss showed over-activation previously observed to lead to disintegration of performance. A major criticism of the procedure was discussed.