Physical Activity in Children & Youth: Benefits, Barriers, and Recommendations

Leslie Solomonian, ND

Benefits of Physical Activity

Physical activity has wide-reaching benefits for children, including improving body composition, academic performance, self-esteem, and bone mass. Physical activity in childhood predicts physical activity in adulthood and reduces the lifetime risk of non-communicable chronic diseases, including cancer and cardiovascular disease, the most significant causes of morbidity and mortality in North America. If anything is a panacea for therapeutic and preventative purposes, it is exercise. However, North American children and youth routinely fail to meet the minimum recommendation of
60 minutes of moderate-vigorous physical activity (MVPA) per day,^1,2 placing them at risk of suboptimal health in childhood and as they become adults. Barriers to activity include lack of enjoyment, positive role models, or safe outdoor spaces, and competition with sedentary activities such as television-watching and video games. Naturopathic doctors can be part of a multi-tiered approach to promote physical activity among children and youth.

Both sedentary behavior and overweight/obesity negatively impact cognition and academic performance.³ A 2013 systematic review of randomized controlled trials demonstrated a positive (albeit small) correlation between acute aerobic physical activity and some domains of cognitive function in children.⁴ A number of other studies have shown positive correlations between physical fitness and cognition as well as academic performance, underscoring the value of incorporating physical activity throughout the school day.^3-6

Engagement in physical activity may improve self-esteem via a number of mechanisms. Children who are less active are more likely to be obese or overweight, which can cause them to experience higher rates of depression and low self-esteem, particularly with respect to athletic aptitude, physical appearance, disordered eating, and peer interactions and bullying.^7,8 MVPA and participation in sports have been demonstrated to reduce rates of depression in children and youth.⁹ Participation in organized sports may improve social functioning, including higher self-esteem, problem-solving capacity, reduced substance use, and reduced depression and anxiety.⁶ The psychosocial benefit of physical activity on cognition, academic performance, and psychosocial health in youth may be dose-dependent.⁶

Weight-bearing, high-impact physical activity plays a critical role in the acquisition of bone mass during adolescence.^9,10 A 2013 study found an association between measures of muscle strength and bone mass density in youth aged 11-16 years.¹¹ The study also noted an inverse correlation between body fat percentage and bone density parameters, suggesting a multi-mechanistic role for the benefit of physical activity on bone health. A more recent systematic review confirmed a positive relationship between bone mass density and body composition, as well as between bone health and levels of physical activity directly.¹² The studies reviewed were interventional trials, suggesting a causative relationship. Peak bone mass predicts adult bone mass; thus, encouraging high-impact physical activity during the pre- and peri-pubescent years may have lifelong benefits.^9,13

Although the causes of obesity are complex and individual, both physical fitness and activity are associated with lower rates of obesity and its comorbidities in children and youth.¹⁴ Interventional trials have demonstrated improvements in body composition parameters in youth, subsequent to physical activity interventions.⁹ Associated with overweight and obesity, a range of studies has demonstrated a positive effect of physical activity on markers of cardiovascular and metabolic disease in youth, including cholesterol profile, insulin sensitivity, and systolic blood pressure.^9,15

There is some evidence that both acute and ongoing physical activity impacts the functioning of the immune system in children.¹⁶ Regular physical activity in children may have a positive effect on atopy and allergy vulnerability, and may reduce the risk of developing cancer over the lifespan.^17,18 Physical activity may be beneficial, not only in promoting health in children, but also in addressing medical concerns including ADHD,¹⁹ cystic fibrosis,²⁰ asthma,²¹ inflammatory bowel disease,²² and childhood cancers.^23-25 The exact nature of optimal recommended activity remains to be determined for prevention and management of inflammatory conditions.¹⁶

The exact associations between sleep quantity and daytime MVPA (and their associated impacts on body composition) are not clear.^26,27 Results from a systematic review suggested that children who engaged in higher levels of MVPA ultimately slept less.²⁶ Other sources suggest that regularity of sleep patterns are associated with increased physical activity.²⁷ An active child may sleep more because he or she requires the rest; a child with insufficient sleep may not have the energy to engage in MVPA; a child who naturally has more energy may innately engage in MVPA and need less sleep. Reciprocity and causation are unclear.

Regular engagement in physical activity may reduce the risk of musculoskeletal tension and pain,²⁸ and appears to be inversely correlated with functional constipation in childhood.²⁹

Risks of Physical Activity in Youth

Physical injuries occur more frequently in children engaged in physical activity, particularly concussive injuries^30,31 and trauma to the extremities.³² Immaturity of the musculoskeletal system^30,33 and activities involving body contact and requiring excessive flexibility may increase the risk of specific traumatic mechanisms. Establishing a baseline of physical fitness and ensuring appropriate technique, equipment, and coaching can reduce the risk of these injuries.^34,35 Effective rest, rehabilitation, and recovery is critical for all athletes.

Some studies have demonstrated that youth involved in sport specifically may have higher levels of negative peer-interactions.⁶ This may be attributed to the inherent competition in sport, which may ultimately increase resilience and problem-solving capacity in young people. The pressure from parents, coaches and peers to perform and specialize at a young age can create stress and loss of enjoyment for young athletes, possibly leading to attrition.³⁵ Considering that most children will not achieve professional levels of athletic competition, physical activity for the purposes of promoting health and wellness, emphasizing fun, sportsmanship, and safe physical activity may be the most successful strategies for encouraging lifelong physical fitness.

Recommendations for Physical Activity

In Canada, guidelines are developed by the Canadian Society for Exercise Physiology and adopted by the Public Health Agency of Canada.^36,37 Guidelines in the United States are developed by the Physical Activity Guidelines Advisory Committee and ratified by the Secretary of Health and Human Services.³⁸ Current recommendations are summarized and compared in Table 1. The benefits of physical activity appear to have a dose-response relationship; in general, more frequent, greater duration, and more vigorous and weight-bearing physical activities yield the most health benefits. For the greatest likelihood of sustainability, activities should be fun, varied, and balanced with appropriate recovery factors (adequate nutrition and rest), with minimal risk for injury. Minimum levels of activity can be achieved through organized sport, unstructured play, and routine household chores and active transportation. A table of suggested activities at varying levels of intensity is provided in the 2008 Physical Activity Guidelines for Americans.³⁸

Despite these clear recommendations, children in North America are failing to achieve even minimum levels of physical activity.¹ The most recent Canadian Health Measures Survey revealed that only 7% of Canadian children and youth accumulate at least 60 minutes of moderate to vigorous physical activity at least 6 days a week. Only one-quarter of children manage to accumulate
30 minutes of activity 6 days per week.²

Barriers and Strategies to Increase Physical Activity

Because of limited independent mobility, most children divide most of their waking time between home and school; thus, school and home-based interventions may be the most beneficial approaches to increasing physical activity among children and youth. A Cochrane review of the value of school-based interventions suggests a small but significant improvement in rates of physical activity, if not a clear beneficial outcome in terms of health parameters.³⁹

Parents play a critical role in the home through role-modeling and support for engagement in physical activity. Parental lack of education and poor modeling directly correlate with low levels of physical activity, particularly in families of lower socioeconomic status and in children with a disability.^40,41 The degree of sedentary behavior engaged in by the parent is a strong predictor of sedentary behavior in the child.⁴² Access to electronic media equipment in the home appears to reduce engagement in physical activity, particularly if devices are permitted in a child’s room.^41,42 Lack of access to athletic facilities and equipment may reduce the likelihood that a child will engage in physical activity. Restrictions on active transport (such as walking or cycling to school or friends’ homes) are also inversely correlated with physical activity in children.⁴³

In one review, giving children the opportunity to play in their local neighborhood seemed to have the most significant impact.⁴³ Parents who engage in physical activity on their own and with their children are more likely to raise children who are physically active.⁴⁴ Emphasizing fun and safety in sport and physical activity is likely to prompt longer participation in children. Access to physical activity equipment in the home, and limitations on time that children spend engaged in sedentary, screen-based activities seem to increase physical activity rates.⁴²

Active transportation, to school and elsewhere, has been positively correlated to physical activity and body composition in children and youth.^1,45,46 Encouraging children to play outside and actively transport yields the added benefits of promoting independence, developing social skills and reducing emissions, and communicates values that are transferrable through the lifespan.⁴⁵ The author wonders if the association may be correlative as opposed to causative, as the amount of time and intensity the typical child spends in active transport is likely less than the recommendations for daily MVPA. However, a family culture in which active transport is encouraged is likely also one that values and encourages physical activity, in general. Of course, the design of the community must be conducive to safe outdoor play and active transport. Investment in effective community design can have tremendous impact on the physical activity and fitness of community members.⁴⁷

Conclusions and Future Directions

Physical activity is a lifestyle behavior that has benefits both deep and wide. Unfortunately, North American children and youth are not achieving even minimum levels. As with all health promotion, the naturopathic doctor can play a number of roles, addressing the issue at multiple levels. Taking the time to inquire about physical activity rates in pediatric patients, and educating caregivers on the benefits, risks, and recommendations for physical activity may be valuable strategies to address key barriers. Identifying activities that the entire family can enjoy together, including active transportation, can increase physical activity in all family members while promoting connection and enhancing relationships. Encouraging caregivers to support their children in participating in organized sport (through school or extra-curricular) and/or lifestyle activities and active play can set the stage for lifelong benefits, both behavioral and health-related. Advising caregivers to limit the time all family members spend engaged in sedentary activities is critical, particularly using electronic digital media; removing digital media from children’s rooms may improve rates of physical activity, as well as media safety and literacy. Engaging in community advocacy at the school or government level to promote affordable, safe access to playgrounds, community centers, competitive and recreational sport opportunities, and active transportation routes can address a higher tier of intervention.

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References:Leslie Solomonian, ND, is a naturopathic doctor in Toronto and assistant professor at the Canadian College of Naturopathic Medicine. She provides instruction in pediatrics, philosophy, and clinical medicine, and supervises medical interns at the Robert Schad Naturopathic Clinic. Leslie has a strong interest in health promotion, knowing that wellness is more than just the absence of disease. Health of the individual child is affected by the well-being of the family, the community, and the environment. As such, Leslie is leading a team at CCNM in developing and evaluating the feasibility of a group-based approach to promoting wellness behaviors in young families.

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