Journal Issue: Childhood Obesity Volume 16 Number 1 Spring 2006
Physical activity is crucial to overall health and to obesity prevention.48 Reduced physical activity is a likely contributor to increasing obesity rates among children of all ages.49
Physical Activity Recommendations for Young Children
The 2005 Dietary Guidelines recommend that children and adolescents engage in at least sixty minutes of physical activity on most, preferably all, days of the week.50 The National Association for Sport and Physical Education's guidelines recommend that toddlers get at least thirty minutes daily of structured physical activity and preschoolers should have at least sixty minutes. It also recommends that toddlers and preschoolers engage in at least sixty minutes a day of unstructured physical activity and not be sedentary for more than sixty minutes at a time except when sleeping. Thus, preschool-aged children should have at least two hours of exercise a day, half in structured physical activity and the remainder in unstructured, free-play settings.51 Children aged five to twelve should have at least sixty minutes of daily exercise.
To help meet the daily physical activity recommendations for preschoolers, experts recommend incorporating planned physical activity into the daily preschool schedule.52 Structured activity sessions should be short, about fifteen to twenty minutes, and should emphasize a wide variety of different movements.53 States vary widely in their physical activity requirements for child care settings, but most address the subject in general, non-quantified terms. The failure to specify how much time children should spend being physically active is an overlooked opportunity to increase physical activity among young children in settings where many spend much of their day.
Physical Activity in Child Care Settings
Surprisingly little is known about the activity levels of children in child care. Russell Pate and several colleagues used accelerometers, or small electronic devices worn around the waist, to record minute-by-minute activity levels of 281 children attending nine preschools (Head Start, church-based, and private) in South Carolina.54 The children, who wore accelerometers for roughly 4.4 hours a day for an average of 6.6 days, participated in a mean of seven minutes an hour of moderate to vigorous physical activity (MVPA) at the preschools. Activity levels varied widely among schools, averaging from four to ten minutes an hour. The preschool that a child attended was a significant predictor of MVPA. The authors speculated that a child attending preschool for eight hours would engage in about one hour of MVPA and would be unlikely to engage in another hour of MVPA outside the preschool setting, suggesting that many preschool children may not be meeting physical activity recommendations. Another study assessed the physical activity level of 214 children aged three to five enrolled in ten child care centers in South Dakota. Each child wore an accelerometer for two continuous days (forty-eight hours).55 The child care center was the strongest predictor of physical activity levels, with more than 50 percent of the daily activity counts occurring between 9 a.m. and 5 p.m. These studies suggest that school policies and practices greatly influence the overall physical activity of the nation's young children.56 The quality and quantity of physical activity in child care settings can vary depending on indoor space, gross motor play equipment, outdoor play area, group size, and the education and training of child care staff.57
The only study to evaluate weight-related differences in physical activity during the preschool day compared the physical activity of overweight and normal-weight three- to five-year- old children while attending preschool.58 The study assessed 245 children, recruited from nine preschools, on multiple days while using both direct observation and accelerometers. It found that overweight boys were significantly less active than normal-weight boys, though it found no weight-related activity differences in girls. Overweight children may thus be at increased risk for further gains in body fat because of low physical activity levels during the preschool day.
Another study of 266 three- to five-year-old children from nine preschools found that preschool policies and practices influenced children's physical activity.59 Children in preschools with frequent field trips (four or more a month) and college-educated teachers had significantly higher levels of MVPA. Children in higher-quality preschools, measured by the number of children per classroom, the educational backgrounds of the teachers, and specific features of the facilities, had lower levels of sedentary behavior. Similar levels of physical activity were observed in private, church-based, and Head Start preschool settings. On average, the children failed to meet current recommendations for physical activity.60 Children in this study were engaged in MVPA about 27 percent of the time, meaning that on average they would have about thirty-two minutes of MVPA in two play periods lasting an hour each. Most notably, the study found higher levels of physical activity in preschools with policies and practices that promoted physical activity.
We could find no studies that assessed children's television and video viewing and computer use in child care centers or day care homes, although it has been reported that children spend more time watching TV in child care homes than in centers.61 Many studies have found a positive link between children's television viewing and obesity, and the American Academy of Pediatrics recommends limiting children's total television viewing time to no more than one to two hours of quality programming a day.62 Future studies should examine television policies and practice in child care facilities.
Research has found that many preschool-aged children are not meeting the recommended guidelines of two hours of physical activity a day and that children in child care settings need more physical activity.63 How active children are in preschools is largely determined by how much time they have to play freely in settings conducive to physical activity, such as outdoor playgrounds, parks, or gyms. One way to ensure that preschoolers get adequate exercise is to provide more time in free-play settings and add structured physical activity to their program.64 As yet, however, no broad policies govern physical activity for preschool children in child care. Although several national groups have published recommendations, no requirements exist at the federal level. Physical activity policies, where they exist, are set by states and facilities.