The purpose of this investigation was to study the pattern of habitual physical activity (HPA) and to assess the time spent in moderate to vigorous physical activity (MVPA) in kindergarten and first-grade schoolchildren. In 54 children, HPA was studied during 4 consecutive days by whole-day heart rate (HR) monitoring. MVPA was defined on the basis of HR threshold above 139 beats per minute. Sustained periods of MVPA of 20 or more minutes were observed only in 20% of boys and 17% of girls. However, the pattern of HPA of all children contained 1-min, and 2- to 4-min periods of MVPA, and 80% of boys and 90% of girls had 5- to 9-min sustained periods of MVPA. It can be concluded that in 4- to 8-year-old children, HPA is characterized by an intermittent pattern without prolonged periods of MVPA.