Patients with schizophrenia have disabling symptoms and cognitive deficits that limit motivation, drive, social- and occupational performance, quality of life and self-efficacy. Schizophrenia also leads to a high risk of dying from cardiovascular disease. Explanatory trials suggest that exercise improves cognitive functioning, symptoms, and quality of life, and reduces the risk of cardiovascular disease. However, due to this illness, the participation in regular exercise is challenging. In this study it will be tested if patients with schizophrenia can participate in long-term exercise therapy, and whether long-term supervised exercise therapy is more beneficial than today's usual care.