Abstract

In order to find out activation level change on a day, 100 college students(50 males and 50 females) were asked to complete short form of the Activation-Deactivation Adjective Check List(AD ACL: Thayer, 1978 b) twice a day(morning and afternoon). Dimension A activation which varies with circadian rhythm is the energetic arousal dimension and Dimension B activation which underlies emotional and stress reactions is tense arousal dimension. Results were found that the level of dimension A activation reduced in the afternoon more than in the morning significantly and the degree of this reduction made a significant difference between sex. The level of Dimension B activation also reduced in the afternoon more than in the morning but not significantly. From these results it would be concluded that the subjects' activation levels varied from energy-calmness to tiredness-calmness under the situation of moderate levels of energy expenditure.