This study examined how activity type influenced heart rates and time spent in target heart rate zones of high school students participating in physical education classes. Significantly higher average heart rates existed for fitness (142 plus or minus 24 beats per minute [bpm]) compared to team (118 plus or minus 24 bpm) or individual (114 plus or minus 18) activities. Similar results occurred for the percentage of activity time spent within a target heart rate zone (fitness 81.7 plus or minus 15.9%, individual 68.4 plus or minus 30.5%, and team 60.6 plus or minus 30.5%). Boys attained higher heart rates during team activities, while female students had higher rates during individual activities indicating male and female adolescents respond differently to activity types. The highest mean heart rates were observed during fitness activities. (Contains 2 tables and 4 figures.)