Abstract Aims Physical activity (PA) is important in patients with heart failure (HF) to improve health outcomes. The adherence to PA is low, and therefore, novel approaches are necessary to increase PA. We aimed to determine the difference in PA in patients with HF who have access to exergaming compared to patients who received motivational support and to explored predictors of a clinically relevant change in non-sedentary time between baseline and 3 months. Methods and results In total, 64 patients (mean age 69 ± 9 years, 27% female) wore an accelerometer 1 week before and 1 week after the intervention. Data were analysed using logistic regression analysis. Patients spent 9 h and 43 min (±1 h 23 min) during waking hours sedentary. There were no significant differences in PA between patients who received an exergame intervention or motivational support. In total, 30 of 64 patients achieved a clinically relevant increase in non-sedentary time. Having grandchildren [odds ratio (OR) 7.43 P = 0.03], recent diagnosis of HF (OR 0.93 P = 0.02), and higher social motivation (OR 2.31 P = 0.03) were independent predictors of a clinically relevant increase of non-sedentary time. Conclusion Clinicians should encourage their patients to engage in alternative approaches to improve PA and reduce sedentary habits. Future exergaming interventions should target individuals with chronic HF who have low social motivation and a low level of light PA that may benefit most from exergaming. Also (non-familial), intergenerational interaction is important to enabling patients in supporting patients in becoming more active.