Project Summary/Abstract Description of the Project: This five-year study will assemble data on the efficacy of aerobic exercise for the treatment of methamphetamine dependence in a population of 150 individuals seeking treatment at Cri-Help residential drug treatment program in Los Angles. After signing consent and satisfying all inclusion/exclusion requirements, participants will be enrolled into the study and undergo baseline assessments during approximately two weeks of treatment as usual. After randomization, participants will enter the Exercise condition (n=75) or the control (Health Education; n=75) condition for an 8-week intervention duration. Incentives for participation in either condition activity (thrice weekly) are fixed at $10 per session. Of the 150 total participants, 30 voluntary participants will be part of a brain imaging substudy. The objective of the imaging substudy is to determine possible brain mechanisms associated with hypothesized effects of exercise on treatment outcomes. The primary goal of the study is to rigorously and comprehensively determine whether inclusion of a aerobic exercise within a residential program improves treatment outcomes in terms of reduced methamphetamine use during the first 12 weeks post discharge and 26 week follow up, as well as to characterize effects of exercise on health, psychiatric symptoms and cognition compared to the control (education) group pre/post intervention. Aims of the study are: Aim 1. To characterize effects of an aerobic exercise intervention (Exercise) compared to health education (Education) in terms of drug use after discharge from residential drug treatment in a population of MA- dependent individuals. Aim 2. To characterize effects of Exercise on MA craving and negative affective states including anxiety, depression, anhedonia, and stress reactivity among participants in residential treatment for MA dependence. Aim 3. To characterize effects of Exercise on neurocognitive functioning. Aim 4. To characterize variations in health-related outcomes among participants in the Exercise condition compared with those in the Education condition. Aim 5. To examine changes in dopamine D2/D3 receptor availability in abstinent MA-dependent participants assigned to an Exercise group compared to a subsample of participants in an Education (control) group (n = 15 per group). Aim 6. To examine differences in addiction-related behaviors (per ASI-type measures) according to intervention condition. There is a critical need for systematic evaluation of strategies for treating methamphetamine use disorders. Thus, this project responds to NIDA request (RFA-DA-09-013) to develop and evaluate an effective exercise-based intervention for addiction.