Background: Main symptoms of the restless legs syndrome (RLS) are sleep onset insomnia and difficulty to maintain sleep. Previous studies showed that regular physical activity can reduce the risk of developing RLS. However, the relationships of physical activity on sleep quality parameters in subjects suffering from RLS have not been investigated by applying accelerometry. Thus, the present study investigates the impact of physical activity during the day (7-12 h, 12-18 h, 18-23 h) on sleep quality in subject suffering from idiopathic RLS as well as their intensity and extent of physical activity by applying a real-time approach.Methods: In a sample of 47 participants suffering from idiopathic RLS, physical activity and sleep quality were captured over one week by using accelerometers. For data analysis physical activity levels and step counts during three periods of a day (morning, afternoon, evening) were correlated with sleep quality parameters of the following night.Results: In this observational study, significant correlations of physical activity with the sleep parameters were rarely confirmed (exception: negative correlation of steps in the morning with periodic leg movements in sleep and negative correlation of physical activity in the evening and total sleep period). However, the physical activity levels of the participants were unexpectedly high compared to population-level data and variance in physical activity was low. The average activity was 13,817 (SD=4,086) steps and 347 (SD=117) minutes of moderate physical activity per day in females and 10,636 (SD=3,748) steps and 269 (SD=69) minutes of moderate physical activity in males, respectively. However, the participants conducted no vigorous physical activity.Conclusions: To investigate the effects of daily physical activity and RLS symptoms interventional studies with different intensities of physical activities at different points of time during the day are needed.