Endocannabinoid and Mood Responses to Exercise in Adults with Varying Activity Levels

Acute aerobic exercise improves mood and activates the endocannabinoid (eCB) system in physically active individuals; however, both mood and eCB responses to exercise may vary based on habitual levels of physical activity. Purpose: This study aimed to examine eCB and mood responses to prescribed and preferred exercises among individuals with low, moderate, and high levels of physical activity. Methods: Thirty-six healthy adults (21 +/- 4 yr) were recruited from low (<= 60 min moderate-vigorous physical activity [MVPA] per week), moderate (150-299 min MVPA per week), and high (>= 300 MVPA per week) physical activity groups. Participants performed both prescribed (approximately 70%-75% max) and preferred (i. e., self-selected) aerobic exercise on separate days. Mood states and eCB concentrations were assessed before and after exercise conditions. Results: Both preferred and prescribed exercise resulted in significant increases (P < 0.01) in circulating eCB (N-arachidonoylethanolamine [AEA] and 2-arachidonoylglycerol); however, increases in AEA (P < 0.05) were larger in the prescribed condition. Likewise, both preferred and prescribed exercise elicited positive mood improvements compared with preexercise values, but changes in state anxiety, total mood disturbance, and confusion were greater in the preferred condition (P < 0.05). Changes in 2-arachidonoylglycerol concentrations were found to negatively correlate with changes in depression, tension, and total mood disturbance in the preferred condition (P < 0.05), and changes in AEA were positively associated with changes in vigor in the prescribed condition (P < 0.05). There were no significant group differences for mood or eCB outcomes. Conclusion: These results indicate that eCB and mood responses to exercise do not differ significantly between samples with varying physical activity levels. This study also demonstrates that in addition to prescribed exercise, preferred exercise activates the eCB system, and this activation may contribute to positive mood outcomes with exercise.