More active, more nature-connected? The carry-over effect of physical activity in pro-environmental behavior.

Carry-over effects describe how one behavior, such as physical activity (PA), can influence another, like pro-environmental behavior (PEB), through psychological mechanisms and the transfer of resources. Three studies have examined the potential carry-over effect and its mechanism between PA and PEB, testing whether psychological mechanisms link the two behaviors and enable the transfer of resources. Study 1 used the China General Social Survey (n = 9,960) and found a significant positive correlation between PAB and PEB, providing preliminary evidence for their interrelation. In pre-registered Study 2, n = 228 college students were examined twice, one month apart, to test the longitudinal carry-over effect from PA to PEB. The results showed that the carry-over effect occurred through a mediating chain of PA intention - PA plans - pro-environmental intention - PEB. In Study 3, a 2 (group: planning intervention group vs. active control group) × 3 (time: baseline vs. post-test vs. follow-up) pre-registered randomized controlled trial was conducted among n = 70 college students. Results showed a time effect with an increase in all dependent variables from baseline to post-test but no interaction effect between time and group. However, we found a significant mediating effect of change in pro-environmental intention between changes in physical activity planning and change in PEB (B = 0.17, 95 % CI [0.05, 0.30]). Overall, the results of these studies demonstrate that planning PA can promote PEB, supporting the hypothesized psychological mechanisms. However, the experimental results from Study 3 require further exploration owing to the absence of a significant interaction effect.