A one- year preventive health behavior-change program for the employees of the company British Petrol (BP) shall be scientifically evaluated. The initial stage of the program consists of a health-behavior seminar and six weeks (twice a week for 90 minutes) of supervised endurance exercise (i.e. jogging, nordic walking, cycling or swimming) in groups. In the second phase of the program, the participants receive a recommendation to continue exercise regularly unsupervised for one year, and receive monthly supervised exercise training sessions. Clinical check-ups are performed at baseline (V1) at three months (V2) and at 12 months (V3).