Today we're discussing the impact of urban green spaces on mental health. A recent study followed 500 residents over two years, measuring their stress levels through cortisol samples. Interestingly, participants who visited parks at least three times a week reported a 20% reduction in stress compared to those who rarely went outside. However, the quality of the green space mattered more than the quantity. For instance, areas with diverse tree species and water features had stronger positive effects than simple grass lawns. The researchers also noted that even brief visits of 10 minutes could lower heart rate, but the effect lasted longer when people engaged in activities like walking or gardening.
❓ According to the lecture, what factor had the greatest influence on reducing stress in urban green spaces?
A. A. Visiting parks at least three times a week
B. B. The variety of trees and presence of water
C. C. The total size of the green area
D. D. Engaging in vigorous exercise for over 30 minutes