Patients will be randomized into 3 groups: 1) Intervention I: 12 week exercise program with low-intensity fitness training 3 times per week. 2) Intervention II: 12 week exercise program with moderate to high-intensity fitness training 3 times per week. 3) Control group, who will have a physiotherapy session once and will be given general advice about physical activity. At baseline, 12 weeks and 1 year data of cardiovascular fitness, anxiety symptoms, cognitive and working ability and biomarkers will be collected.