The Effect of Unstructured Versus Structured Cardio Exercise on Mood and Physiological Reactivity to Stress

Purpose: Physical activity (PA) reduces stress-related physiological responses and anxious behavior. However, only ~40% of college-aged students meet physical activity recommendations. Unstructured PA provides increased social interaction and support. The purpose of this study was to examine the effect unstructured physical activity has on mood and physiological responses to an acute stress compared to structured aerobic activity in college students. Methods: Twelve participants (age 18-22 years, 4 males & 8 females) were recruited. Baseline heart rate (HR), blood pressure (BP), and mood were recorded. Participants were then randomized to either unstructured (Ultimate Frisbee) or structured (treadmill) PA groups. HR was recorded throughout the 15-minute PA session. HR and BP reactivity to the Stroop task was measured following a 15-minute recovery period post-exercise. Results: Heart rate was significantly elevated throughout both the structured and unstructured PA sessions (ave. 169±21 & 169±10 bpm, respectively). The Stroop task significantly increased HR and BP in both groups, with no significant difference between groups. Mood ratings improved significantly following unstructured PA but not structured PA. Conclusion: Our results suggest that no significant physiological difference in stress response occurs between acute bouts of structured and unstructured PA, but there is an additional decrease in mood disturbance following unstructured PA