Lifestyle Interventions for Generalized Anxiety Disorder

Inclusion Criteria: * Male and female participants, ages 18-65. * Principal diagnosis of Generalized Anxiety Disorder. * Willing to and capable of providing informed consent, attending all study visits, and complying with the protocol. * Classified as either being at low risk or moderate risk for cardiovascular disease according to American College of Sports Medicine (ACSM) risk stratification guidelines (see "Telephone Prescreen and Risk Stratification" section for more information). * Sedentary as defined by ACSM guidelines as not participating in at least 30 minutes of moderate-intensity exercise on at least 3 days a week for at least 3 months. Exclusion Criteria: * Currently suicidal or high suicide risk, current or past psychotic disorders of any type, bipolar disorder (I, II, or NOS), schizophrenia or schizoaffective disorder, anorexia, bulimia. Alcohol or drug dependence, abuse of depressants, dissociative anesthetics, hallucinogens, opioids, and cocaine within the last 6 months. Comorbid psychiatric conditions that are relative or absolute contraindications to the use of any treatment option in the protocol. * Cognitive behavioral therapy within three months of baseline, or ongoing supportive therapy directed specifically toward the treatment of anxiety or mood disorder. * Psychotropic medications are acceptable only if they are stabilized for at least 3 weeks prior to the baseline visit, as long they are not considered a relative or absolute contraindication to the use of any treatment option in the protocol. * For women, currently pregnant, plans to be pregnant in the next year, or currently breastfeeding. * Insufficient command of the English language (i.e., they cannot carry on a conversation with an interviewer in the English language or read associated text).