The purpose of this study was to examine if a 1-year lifestyle intervention study (cycling to work) has an influence on coronary heart disease (CHD) risk factors and health-related quality of life, in previously untrained healthy adults. Healthy, untrained men and women, who did not cycle to work, participated in an intervention study. Sixty-five subjects (intervention group: IG) were asked to cycle to work at least 3 times a week and 15 controls (CG) were asked not to change their living habits. All measurements were performed on 3 consecutive occasions, with 6 months in between. Physical performance, venous blood samples, blood pressure (BP), and the SF-36 Health Status Survey were assessed. Cycling characteristics and leisure-time physical activities were reported in a dairy. Total cholesterol (TC), LDL, TC/HDL and diastolic BP decreased and HDL increased significantly in the IG. TC and LDL decreased significantly in the CG. Vitality for the total group and physical functioning for women significantly changed over time between IG and CG in the first 6 months. These results show that cycling to work has a positive influence on CHD risk factors and is likely to improve the health-related quality of life in previously untrained healthy adults.