Q:HOW MUCH ACTIVITY DO KIDS NEED? WHAT TYPES OF ACTIVITIES SHOULD BE ENCOURAGED? WHAT ARE THE BENEFITS OF BEING ACTIVE?
A:Physical activity is important throughout the life span — from birth onward! Although the exercise prescription will change across time, age-appropriate physical activity is recommended for everyone, including infants, toddlers, preschoolers, school-aged youth, adults, and older adults. Identifying enjoyable physical activities has the potential to motivate youth to be active and to continue that activity into adulthood.
RECOMMENDED ACTIVITY LEVELS
The National Association for Sport and Physical Activity (NASPE) provides guidelines for physical activity for infants (defined as birth to 12 months of age), toddlers (12 to 36 months of age), and preschoolers (3 to 5 years of age) in “Active Start: A Statement of Physical Activity Guidelines for Children from Birth to Age 5” (see the list of guidelines at http://www.aahperd.org/naspe/standards/nationalGuidelines/ActiveStart.cfm) (10). The position of NASPE is that infants, toddlers, and preschoolers should engage in daily physical activity that “promotes movement skillfulness and foundations of health-related fitness” (10).
Physical activity recommendations for infants include interactions with caregivers that focus on exploring movement and the infant’s environment, physical activity recommendations for toddlers include structured physical activity for at least 30 minutes and unstructured physical activity of at least 60 minutes (up to several hours) each day, and physical activity recommendations for preschoolers include structured physical activity for at least 60 minutes and unstructured physical activity of at least 60 minutes (up to several hours) each day (10). Structured activities are those directed by an adult, for example, dancing to rhythms or moving through an obstacle course. Unstructured activities are those initiated by the child, for example, climbing on playground equipment or riding a tricycle. In addition to promoting time for physical activities, NASPE recommends avoiding sedentary behavior of more than 60 minutes at a time, except when sleeping, for toddlers and preschoolers (10).
NASPE also promotes physical activity for preadolescent children (ages 5 to 12 years), with the following recommendations (11):
* accumulate at least 60 minutes (up to several hours) of moderate and vigorous physical activity on all (or at least most) days of the week (note that most physical activity is done intermittently)
* include several bouts of 15 minutes or more each day
* discourage extended time (2 hours or more) of inactivity during daytime hours
(For a list of NASPE Guidelines see http://www.aahperd.org/naspe/standards/nationalGuidelines/PA-Children-5-12.cfm).
Incorporating a slightly wider age range, the recommended exercise prescription for children and adolescents (defined as 6 to 17 years of age), as described in the 2008 Physical Activity Guidelines for Americans (18) and the 9th edition of the American College of Sports Medicine’s (ACSM) Guidelines for Exercise Testing and Prescription (1), is summarized in the Table that includes the frequency, intensity, time, and type of activity (FITT). These recommendations are in line with those of the World Health Organization (see summary sheet: http://www.who.int/dietphysicalactivity/physical-activity-recommendations-5-17years.pdf?ua=1) (21) as well as the American Heart Association (2) that recommends “children and adolescents participate in at least 60 minutes of moderate to vigorous physical activity every day.”
IMPACT OF PHYSICAL ACTIVITY FOR YOUTH
Being physically active promotes many benefits for the youth, including better academic performance, better school attendance, improved behavior, and higher self-esteem (15). In addition, symptoms of anxiety and depression may be reduced (18). The Physical Activity Guidelines for Americans highlight the characteristics of physically active youth, including the following (18):
* Higher levels of cardiorespiratory fitness
* Stronger muscles
* Stronger bones
* Lower body fatness (typically)
Box 1 includes various measures used within schools as part of the Presidential Youth Fitness Program (including aerobic capacity, muscular fitness, body composition, and flexibility) (15).
The chance of a healthy adulthood is better for youth who are physically active (18). Chronic diseases (e.g., heart disease, type 2 diabetes) are “chronic” because they take time to develop and thus youth usually do not experience chronic diseases. Unfortunately, risk factors for these diseases can start to develop at early ages, especially when the youth are not engaging in regular physical activity (18). For example, the potential benefits of a comprehensive exercise program for children, including resistance exercise, are supported by a recent study that found that greater relative strength and physical activity are factors associated with cardiometabolic health as reflected by the following measures: percent body fat, systolic blood pressure, triglycerides, high-density lipoprotein, and blood glucose (14).
Regular physical activity can help promote healthy body weight (18). Overweight and obesity are concerns for children (Figure 1). Children who are overweight or obese are more likely to remain so into adulthood and, in turn, are more likely to develop diseases such as diabetes and cardiovascular disease at a younger age (21). The World Health Organization points to a number of factors related to global increases in childhood overweight and obesity, including “A trend toward decreased physical activity levels due to the increasingly sedentary nature of many forms of recreation time, changing modes of transportation, and increasing urbanization” (21). Thus, creating opportunities and environments for youth to engage in enjoyable, safe, and effective physical activity is key not only for current health but also potentially future health as well (see Box 2 for considerations on maximizing safety).
In 2012, about one quarter of U.S. youth 12 to 15 years of age engaged in moderate-to-vigorous physical activity for at least 60 minutes daily, specifically, 27% of boys and 22.5% of girls (Figure 2) (7). Ideally, 100% of youth would meet the target of 60 minutes of daily activity! Although that target is currently unmet, many of the youth surveyed are including activity on most days of the week; more than one half (60.2%) of boys surveyed and about one half (49.4%) of girls engaged in moderate-to-vigorous physical activity for at least 60 minutes on 5 days or more each week (see boxed section on Figure 2) (7). Unfortunately, 7.6% of youth are not active for 60 minutes on any day of the week, specifically 6.4% of boys and 8.7% of girls (see circled area in Figure 2) (7). The top activities outside of school-based physical education classes for 12- to 15-year-old adolescent boys included basketball (48.0%), running (33.5%), football (27.4%), bike riding (24.0%), and walking (23.6%). Among 12- to 15-year-old adolescent girls, the top activities included running (34.9%), walking (27.6%), basketball (21.4%), dancing (20.8%), and bike riding (18.4%) (7).
Physical activity levels tend to decline during adolescence (see Box 3 for information on differences between self-reports compared with objectively measured physical activity). One review involving 26 studies found that the mean yearly decline in physical activity was approximately 7% (5). Considering this trend, some have suggested that maintaining physical activity, attenuating the decline in activity often observed, should be considered effective (5).
When examining trends in aerobic fitness, researchers at the 2013 American Heart Association annual meeting reported that cardiovascular endurance has declined since 1975. This study included an analysis of 50 studies published between 1964 and 2010 on running fitness; this analysis included more than 25 million youth between the ages of 9 to 17 years from 28 different countries (3). Some of the findings presented included (3):
* In the United States, cardiovascular endurance fell an average of 6% per decade between 1970 and 2000.
* Across nations, endurance has declined consistently by about 5% every decade.
* Kids today are roughly 15% less fit from a cardiovascular standpoint than their parents were as youngsters.
* In a mile run, kids today are about a minute and a half slower than their peers 30 years ago.
These results underscore the need to encourage physical activity.
FACTORS INFLUENCING ACTIVITY
Understanding what factors foster physical activity is crucial to effectively promoting regular physical activity among youth. Family and home environments have many potential sources of impact, including presenting role models (parents or siblings) and providing social support (9). A study of grade five students in Canada (aged 10 to 11 years) during the school year supports the importance of support from parents to increase children’s level of physical activity (19). Researchers found physical activity levels to be lower on weekends than on school days; however, the physical activity of children was associated with parental support and encouragement (19).
In addition to opportunities for activity at home during weekends and after-school periods, there is opportunity to encourage physical activity at school. Physical education and recess are examined in the 2012 Shape of the Nation Report: Status of Physical Education in the USA (12). Although 75% of states mandate that schools must provide students with physical education, only six states require physical education in all grades from kindergarten through high school (Illinois, Hawaii, Massachusetts, Mississippi, New York, and Vermont). NASPE recommends that schools provide 150 minutes of physical education each week for elementary schoolchildren, increasing to 225 minutes per week for middle and high school youth. Physical education includes instruction and feedback so the youth will have the skills needed to continue to be active throughout their life span (12). Also, within the school day, recess is a time for elementary schoolchildren to be active; only nine states (18%) require elementary schools to provide students with recess.
School-based programs have the potential to create environments that support increases in physical activity (6). For example, implementation of a comprehensive school health program, Alberta Health’s Healthy Weights Initiative, included access to a school health facilitator and strategies/materials to promote healthier lifestyles; physical activity was measured by the number of steps per day and steps per hour for school days and nonschool days (20). This intervention led to higher levels of physical activity both on school days and nonschool days (i.e., extending beyond the school environment). As another example, a 9-month physical activity intervention, FITKids, which provided 70 minutes per day of intermittent moderate-to-vigorous physical activity on 5 days per week (the 2-hour program included fitness activities for 20 to 25 minutes, healthy snack during a 15-minute education component, games or sports activities for 50 to 55 minutes, and then a 15-minute cooldown), improved cardiorespiratory fitness and body composition (reduced total percent fat and prevented changes in central adiposity) among prepubertal boys and girls; these changes were found for nonoverweight and overweight or obese participants, whereas the control group experienced no change in aerobic fitness and had unfavorable changes in body composition (8). These results support the value of meeting the recommended 60 minutes per day of physical activity.
Ultimately, collaboration among families, schools, community leaders, and health care professionals is key to creating environments for the youth that encourage active healthy lifestyles. Recommendations include social marketing that promotes physical activity, representation by physicians on school wellness councils, advocacy for school curriculum that teaches the health benefits of physical activity, daily physical education taught by qualified trained instructors who have adequate resources to provide safe, enjoyable activities, physical activity opportunities in addition to physical education (e.g.,recess),andthedevelopmentof activity-promoting environments (e.g., parks, playgrounds, bike paths) (4). In addition, health care professionals should serve as role models themselves, as well as inquiring about activity levels during health care visits and encouraging physical activity (4). Many excellent sources of information are available (see Box 4 for some Web-based resources).
Age-appropriate physical activity is recommended for everyone, including infants, toddlers, preschoolers, school-aged youth, adults, and older adults. Regular physical activity promotes fitness and is related to many other benefits (e.g., better academic performance, higher self-esteem, reduced anxiety). Through collaboration among families, schools, and communities, physical activity habits in the youth can serve as a foundation for continued physical activity into adulthood.
1. American College of Sports Medicine. ACSM’s Guidelines for Exercise Testing and Prescription. 9th ed. Philadelphia (PA): Lippincott Williams & Wilkins; 2014.
4. Council on Sports Medicine and Fitness and Council on School Health. Active healthy living: prevention of childhood obesity through increased physical activity. Pediatrics. 2006; 117: 1834–42.
5. Dumith SC, Gigante DP, Domingues MR, Kohl HW III. Physical activity change during adolescence: a systematic review and a pooled analysis. Int J Epidemiol. 2011; 40: 685–98.
6. Dobbins M, Husson H, DeCorby K, LaRocca RL. School-based physical activity programs for promoting physical activity and fitness in children and adolescents aged 6 to 19 (Review). The Cochrane Library. 2013; 2: 1–260.
7. Fakhouri THI, Hughes JP, Burt VL, et al Physical Activity in U.S. Youth Aged 12–15 Years, 2012. NCHS Data Brief No. 141. Hyattsville (MD): National Center for Health Statistics; 2014.
8. Khan NA, Raine LB, Drollette ES, et al Impact of the FITKids physical activity intervention on adiposity in prepubertal children. Pediatrics. 2014; 133: e875–83.
9. McMinn AM, Griffin SJ, Jones AP, van Sluijs EMF. Family and home influences on children’s after-school and weekend physical activity. Eur J Publ Health. 2012; 23 (5): 805–10.
10. National Association for Sport and Physical Activity. Active Start: A Statement of Physical Activity Guidelines for Children from Birth to Five Years. 2nd ed. Reston (VA): National Association for Sport and Physical Activity; 2009.
11. National Association for Sport and Physical Activity. Physical Activity for Children: A Statement of Guidelines. 2nd ed. Reston (VA): National Association for Sport and Physical Activity; 2009.
12. National Association for Sport and Physical Education & American Heart Association [Internet]. 2012 Shape of the Nation Report: Status of Physical Education in the USA. Reston (VA): American Alliance for Health, Physical Education, Recreation and Dance; 2012; [Accessed 2014 Mar 19]. Available from: http://www.aahperd.org/naspe/publications/Shapeofthenation.cfm
13. National Center for Health Statistics. Health, United States, 2012: With Special Feature on Emergency Care. Hyattsville (MD): National Center for Health Statistics; 2013; [Accessed 2014 Mar 5]. Available from: http://www.cdc.gov/nchs/hus.htm
14. Peterson MD, Saltarelli WA, Visich PS, Gordon PM. Strength capacity and cardiometabolic risk clustering in adolescents. Pediatrics. 2014; 133: e896–e903.
15. President’s Council on Fitness, Sports & Nutrition [Internet]. Presidential Youth Fitness Program. Rockville (MD): President’s Council on Fitness, Sports & Nutrition; [cited 2014 Mar 5]. Available from: http://www.pyfp.org/
16. Presidential Youth Fitness Program (2013). Presidential Youth Fitness Program Physical Educator Resource Guide (Internet Resource). Silver Spring (MD): National Foundation on Fitness, Sports and Nutrition; 2013; [cited 2014 Apr 7]. Available from: http://www.pyfp.org/doc/teacher-guide.pdf
17. Troiano RP, Berrigan D, Dodd KW, Masse LC, Tilert T, McDowell M. Physical activity in the United States measured by accelerometer. Med Sci Sports Exerc. 2008; 40 (1): 181–8.
18. U.S. Department of Health and Human Services Web site [Internet]. 2008 Physical Activity Guidelines for Americans, 2008. Atlanta (GA): USDHHS; [cited 2011 Aug 2]. Available from: http://www.health.gov/paguidelines
19. Vander Ploeg KA, Kuhle S, Maximova K, McGavock J, Wu B, Veugelers PJ. The importance of parental beliefs and support for pedometer-measured physical activity on school days and weekend days among Canadian children. BMC Public Health. 2013; 13: 1132.
20. Vander Ploeg KA, McGavock J, Maximova K, Veugeler PJ. School-based health promotion and physical activity during and after school hours. Pediatrics. 2014; 133; e371–8.
21. World Health Organization [Internet]. Global strategy on diet, physical activity and health: Childhood overweight and obesity. Switzerland: WHO Prevention of Noncommunicable Diseases; [accessed 2014 Mar 19]. Available from: http://www.who.int/dietphysicalactivity/childhood/en/