BackgroundPreschools may provide opportunities for children to engage in physical activity (PA), to benefit their health, although little is known when concerning low-income preschoolers. This study aimed (1) to describe time spent in PA among low-income children during preschool hours and (2) to analyse how many children meet the PA recommendations during preschool hours.MethodsA total of 204 low-income preschoolers (4.51 +/- 0.79 years) from Joao Pessoa/Brazil provided valid accelerometer (Actigraph, WGT3-X) data during the preschool period. Children were grouped in quartiles of PA in counts per minute, according to sex and age. The General Linear Model Univariate was used to examine the differences in PA intensities between the quartiles and the time spent in total PA (TPA) and moderate-to-vigorous PA (MVPA) by quartiles, according to age. An hour-by-hour description of children's PA was presented.ResultsTPA during preschool hours ranged from 68.33% to 113.89% of the recommended and from 28.34% to 81.68% of the MVPA recommendations. Among 5-year-old children, those in the highest quartile met the PA recommendations. All children were more active outdoors than indoors. For the less actives, preschool time corresponded to 30% of the recommended daily MVPA.ConclusionThe current results reinforce the importance of preschool settings for promoting preschoolers' PA and provide particularly important and useful information for tailoring preschool-based interventions focused on those who need it most. Strategies to increase children's MVPA should be prioritized during free-play time.