The relationships between nocturnal motor activity and daytime psychophysiological activation were investigated in a random community sample of 199 subjects aged 35-55 years. Nocturnal motor activity was recorded with the static charge sensitive bed (SCSB, Bio-Matt). The association of nocturnal motor activity with demographic features, health status, laboratory blood values, afternoon electrodermal activity (EDA) and psychological distress was studied. A model for nocturnal motor activity was constructed and statistically analyzed. The analysis revealed that psychological distress, breathing disturbance, plasma glucose level and sympathetic activity were related significantly and independently to nocturnal motor activity. Their relations and the associations of sex, age, body mass index (BMI), sleep latency and health status with nocturnal motor activity were discussed in the context of the arousal theory of poor sleep.