Genetic and environmental influences on objectively assessed activity in adults

We objectively assessed motor activity level in a community sample of 300 adult monozygotic and dizygotic twin pairs as part of the German Observational Study of Adult Twins (GOSAT). The participants carried motion recorders (actometers) over a period of approximately 6 h to assess limb movements while engaging in a variety of tasks. Behavioral genetic analyses of an actometer composite score (ACS) suggested moderate genetic influence (a2=0.40) and no shared environmental influences on this objective measure of activity. Furthermore, ACS showed small to moderate meaningful and significant relations to several activity-related temperament dimensions assessed via self- and peer reports. A series of bivariate analyses yielded mixed results with regard to genetic and environmental influences on the covariation between objectively assessed activity and self-reported temperament.