PURPOSE: To objectively assess, in stable cardiac patients, the adherence to physical activity (PA) recommendations using an accelerometer at 2 or 12 months after the discharge of cardiac rehabilitation program (CRP). METHODS: Eighty cardiac patients wore an accelerometer at 2 months (group 1, short-term adherence, n = 41) or one-year (group 2, long-term adherence, n = 39) after a CRP including therapeutic education about regular PA. PA was classified as "light" (1.8-2.9 Metabolic Equivalent of Task [METs]), "moderate" (3-5.9 METs), or "intense" (>6 METs). Energy expenditure (EE, in Kcal) and time (min) spent in these three different levels were measured during a one-week period with the MyWellness Key actimeter (MWK). Motivational readiness for change was also assessed at the end of CRP. Patients were considered as physically active when a minimum of 150 min of moderate PA during the one-week period was achieved. RESULTS: Both groups were comparable, except for exercise capacity at the end of the CRP which was slightly higher in group 1 (167.5 +/- 42.3 versus 140.7 +/- 46.1 W, P < 0.01). The total weekly active EE averaged 676.7 +/- 353.2 kcal and 609.5 +/- 433.5 kcal in group 1 and 2, respectively. The time spent within the light-intensity range PA was 319.4 +/- 170.9 and 310.9 +/- 160.6 min, and the time spent within the moderate-intensity range averaged 157.4 +/- 115.4 and 165 +/- 77.2 min per week for group 1 and 2, respectively. Fifty-three percent and 41% of patients remained active in both groups respectively. CONCLUSION: About half of the patients are non-adherent to PA after CRP and do not reach target levels recommended by physicians. The first 2 months following the discharge of CRP seem to be of outmost importance for lifestyle modifications maintenance, and further study monitoring more closely PA decrease could help to clarify the optimal follow-up options.