|| This study was undertaken to give scientific basis in introducing exercise into our daily lives. Fatigue scores, the Flicker value, the counter value, grip strength and counting steps were analyzed in 109 female high school students before and after physical education classes during the third school period. These female students were chosen because of their lower fatigue scores, particularly before lunch time. Fatigue scores were obtained in tumbling exercises, softball, badminton, team handball, basketball and a 2.2-km distance run during 50-min classes. Step-counting activities were the lowest in tumbling with 640 steps, and the highest in the 2.2-km distance run with 2,580 steps. In all activities except the distance run, fatigue scores decreased, and the Flicker value and the counter value increased after exercise. Grip strength decreased only in softball and the distance run. In the distance run, all measurements of the tests showed tendencies toward fatigue. However, with lighter exercises, the fatigue scores decreased by 1,760 steps; also, the Flicker value and the counter value showed improvement of physical function. Therefore, it is suggested that exercise having around 1,760 steps, corresponding to approximately 35 steps/min, might be the upper limit of physical load at which fatigue symptoms increase in a physical education class. Physical activities in the physical education classes showed two types of effects: recreational effects and training effects.