RecruitingBehavioural interventionExercise-priming of CBT for Depression: the CBT+ TrialThis study investigates the effects of intentionally sequencing aerobic exercise immediately prior to cognitive behavioral therapy (CBT) to determine its effects on mechanisms of CBT (i.e., working alliance, behavioral activation). To assess the utility of this treatment augmentation, investigators will conduct a randomized controlled trial involving 100 adults with Major Depressive Disorder who will watch a nature documentary while either resting quietly ( 'CalmCBT') or exercising at a moderate intensity ('ActiveCBT') immediately prior to 8 weekly sessions of CBT.