Effects Of Acute Exercise, Stretching, And Meditation On Salivary Endocannabinoids In Youth: Preliminary Findings From A Pilot Study

BACKGROUND: The endocannabinoid system (eCB) plays an important role in many physiological processes, including stress response. Desai (2021) reports that exercise in adults may promote elevations in key eCB markers and may contribute to stress reduction. A main limitation of studies exploring the eCB system, especially in youth samples, is the need for blood samples. However, recent research in adults detected eCBs in saliva. Ney et al. (2021) report adult baseline levels for two key eCB markers as around ~2.0 pmol/ml for AEA and ~ 200 pmol/ml for 2-AG. PURPOSE: Given the promise of salivary eCB as a less invasive option, this study explores how salivary eCBs are expressed in youth as well as how they may change, under stress. METHODS: Youth ages 9-17 (M = 13.2 years) from the Metro Detroit (N = 68) were randomly assigned to 30 minutes of treadmill walking (exercise, n = 8), stretching (n = 8), or meditation (n = 5) groups. Pre- and post-intervention saliva was collected in a subsample (n = 32) of participants. Descriptive statistics were used to compare youth baseline salivary eCB levels to adult levels. Repeated measures ANOVA was used to assess changes in salivary eCB levels by stress condition and time. RESULTS: Baseline salivary means were AEA = 0.42 pmol/ml ± 1.2 and 2-AG = 88.4 pmol/ml ± 22.5. A significant main effect of time for AEA (p = 0.003), indicated a decrease across all groups from pre- to post; however, no main effect of group or time × group interaction was found. Salivary PEA and SEA also showed significant main effects of time (p = 0.001 and p = 0.005, respectively) but no effects of group or time × group interaction, with no significant effects of age or gender on outcomes. OEA and LEA revealed no significant main effects. CONCLUSIONS: To the best of our knowledge, this is the first study to assess eCB levels in youth. These preliminary findings suggest that exercise and meditation may influence stress-related biomarkers in youth. Further research is needed to determine if saliva provides a reliable measure of eCB markers in youth, given the large variation in baseline measures across youth and adults and the lack of standardized reference values or clear stress response profiles for this population.