Placebo-driven Anxiolytic Benefits Of Resistance Exercise Training Among Young Women With Subclinical Generalized Anxiety Disorder

: Associations between baseline and changes in expectations of anxiolytic responses to resistance exercise training (RET) and actual anxiolytic responses to RET are critically understudied. PURPOSE: To quantify associations between baseline and changes in expectations of anxiolytic responses to RET and actual anxiolytic responses to RET in young women with analogue Generalized Anxiety Disorder (AGAD). METHODS: 39 young women (21.8 ± 2.5y) with AGAD (Psychiatric Diagnostic Screening Questionnaire GAD subscale ≥6 and Penn State Worry Questionnaire ≥45) completed 10 weeks of twice-weekly, ACSM guidelines-based, ecologically valid moderate to high dose (~80% 1RM; n = 22) or low dose SHAM RET (~20% 1RM; n = 17). Anxiety symptoms (via State Trait Anxiety Inventory) and expectations regarding changes in anxiety response to RET (via Expected Psychological Outcomes of Resistance Exercise Training Questionnaire) were measured pre- and post-10-weeks of RET. A two (group) x five (time) RM-ANOVA examined differences between low and moderate to high doses. Hedges’ d effect sizes (95%CI) quantified the magnitude of differences in change between groups. Cohen’s d effect sizes (95%CI) quantified the magnitude of within-group change. Spearman’s rank correlations quantified associations between expectations and anxiety change scores. RESULTS: The group X time interaction was not significant (F(3.10,113) = 0.69, p ≥ 0.56, d = 0.30, [95%CI: -0.35 to 0.93]). The main effect for time was significant (F(3.10,113) = 20.47, p = <0.001); anxiety was reduced for moderate to high (d = 1.10 [ 0.47 to 1.73]) and low doses (d = 0.62 [-0.07 to 1.31]) at 10 weeks. Baseline expectations of anxiety responses were not associated with response for moderate to high (rho = -0.05, p ≥ 0.98) RET, but were associated with response for low (rho = 0.60, p ≤ 0.01) dose. Changes in expectations of anxiety responses were not associated with actual anxiety responses for moderate to high (rho = 012, p ≥ 0.61) or low (rho = -0.94, p = 0.72) doses. CONCLUSIONS: 10 weeks of guidelines-based moderate to high dose and low dose SHAM RET significantly reduced anxiety in young women with AGAD. Baseline expectations of anxiety responses were associated with actual anxiety response to low dose RET, and may be a modifiable feature to prime anxiety response to RET.