Michigan Governor's Council on Physical Fitness, Health and Sports

Position Statement:

Importance of Physical Activity for Children and

Youth

Written by James M. Pivarnik, PhD

Contents:


Position

One of every two children in Michigan today is likely to die prematurely from preventible cardiovascular disease or preventible cancer. Two major contributors to chronic disease - sedentary lifestyle and excess weight - are becoming more prevalent with each passing year. The Michigan Governor's Council on Physical Fitness, Health and Sports believes regular physical activity to be essential to the mental and physical health of each child and adolescent in Michigan. Positive exercise habits formed in childhood frequently carry over into adulthood and may help reduce death and illness from chronic disease. We can and must develop policies which save the lives of our children from preventible chronic disease. We recommend the following:

Exercise Recommendations

Policy Recommendations for Schools

Policy Recommendation for Health Professions

Policy Recommendation for Communities


Introduction

The cost of treating coronary heart disease (CHD) and other chronic cardiovascular disease in adults comprises a significant portion of U.S. total health care costs.11,34 In Michigan, $23.9 billion was spent on health care in 1990.39 An increase of 129%, (i.e., expenditures greater than $54 billion) is projected by the year 2000. In the State of Michigan, mortality from heart disease is higher than the national average and is the leading cause of death (34%).39,40 Risk factors for cardiovascular disease in both adults and children are also greater in Michigan, as compared to the national average.32,39,40 The most prevalent chronic disease risk factor among Michigan citizens is physical inactivity.12

Recent investigations have clearly shown that low aerobic fitness and habitual physical inactivity are independently related to increased cardiovascular disease risk in adults.7,19, 47 The good news is that recent studies also indicate that a total of 30 minutes of moderate physical activity performed most days of the week has a significant impact on prevention of cardiovascular and other chronic diseases.50 These numbers should be attainable by the majority of Michigan children and youth if they are given the proper instruction, encouragement, and motivation.

However, encouragement and motivation will definitely be needed. Available statistics indicate that few of our children are exercising at even the lowest acceptable levels for health. The 1990 Youth Risk Behavior Survey found that only 37% of all students in grades 9-12 reported being vigorously active three or more times per week.10 The values were significantly lower in females compared to males (24.8% vs 49.6%), and lower in African-American students (29.2%) compared to either Caucasians (39.3%) or Hispanics (34.5%). These physical activity patterns are consistent with those of adults.27 More recently, results from the 1992 Youth Risk Behavior Survey indicated only 26.3% of individuals from ages 12-21 engage in at least "moderate" physical activity on a daily basis.12 Because cross sectional studies have shown girls' cardiovascular fitness levels begin to decline during the peripubertal period, the female adolescent population is of particular concern.29

The Centers for Disease Control and Prevention (CDC) recently released a statement that declining physical activity and fitness may be evident by ninth grade, and recommended interventions to increase physical activity, targeted at school-aged youth to help break patterns of sedentary lifestyle that currently exist in the U.S.36 We have a long way to go to improve physical activity levels among our children, but the goal is critical and is absolutely achievable. Since adult physical activity patterns and aerobic fitness can often be traced to childhood,9,14 it is reasonable to expect that healthy physical activity patterns initiated at a young age will persist through adulthood. Now is the time for us to contain the projected escalating health care costs in the coming century and protect the health of present and future Michigan citizens.


History of the Issue

Health care professionals have long understood the importance of physical activity for children. Exercise has traditionally been prescribed as a treatment for children suffering from chronic diseases such as asthma, cystic fibrosis, and insulin dependent diabetes, for whom regular physical activity may reduce both morbidity and mortality.24,45,46,57

Early studies of healthy children's exercise habits and physical fitness primarily focused on assessing muscular strength, speed, and power. In the 1950's, interest escalated when a research study found U.S. children to be less fit than Europeans.30 As a reaction to this finding, the President's Council on Youth Fitness was established in 1956. Soon afterward, The American Alliance for Health Physical Education and Recreation developed a youth fitness test battery designed primarily to measure motor performance skills.3

Because epidemiologic data show that chronic and degenerative diseases of adulthood have their roots in childhood, there has been concern that traditional physical education curricula and motor performance tests were not adequate to prevent risk factors associated with these diseases56 or evaluate the presence of these problems.31,70 In response to these concerns, current youth fitness testing has evolved into a more health-related format, replacing the traditional motor skill emphasis.2,23 For example, test items include a mile walk/run to estimate aerobic fitness, and skinfold thickness measurements to estimate percent body fat. In addition, criterion scores have been set, based on current research findings, so students can be more appropriately judged in terms of overall health, rather than simply compared to one another.

At the present time, there is not consensus on criteria for minimum fitness standards, or even whether physical fitness has significantly declined in recent years in the majority of our youth.6,13,33,67 However, there is a virtual consensus that children and youth should be involved in physical activity on a regular basis, and that teaching/reward systems should encourage active participation and enjoyment by all students, not just the highly skilled. Indeed, it is the children who are the least successful in traditional sports and athletics who are most likely to be physically inactive.

In recognition of the importance of exercise as a preventive measure for chronic disease, the Michigan Association for Health, Physical Education, Recreation and Dance (MAHPERD) issued a position statement in 1989 emphasizing the value of quality physical education programs in Michigan schools during the 1990's.38 This statement was a good first step and is currently being followed up by the Michigan Exemplary Physical Education Curriculum Project, a state-wide effort by the Governor's Council on Physical Fitness Health and Sports and the Michigan Fitness Foundation to revamp school physical education curricula to reflect the recommendations put forth in the MAHPERD position.


Scientific Basis

Recent studies have clearly shown that early signs of chronic disease and risk factors for chronic disease such as elevated cholesterol and hypertension which would be considered normal in a middle-aged population can be found in children.35,42,60 Several studies have documented that the presence of chronic disease risk factors in children is associated with low aerobic fitness and low levels of physical activity.62,65,66

Physical inactivity has been shown to be a significant predictor and cause of obesity in children, independent of nutritional habits.15 In the U.S., children's obesity appears to be increasing,21 with sedentary activities such as television viewing having replaced recreational pursuits that involve more physical activity.51 This becomes problematic since children with the lowest physical activity/fitness levels, and highest percentage of body fatness are most likely to develop other risk factors for cardiovascular disease, including elevated blood pressure and serum cholesterol levels.16,71 It is encouraging to note that weight and blood pressure can be lowered in children when physical activity is an integral part of the treatment regimen.55

Unfortunately, many cardiovascular disease risk factors tend to "track" over time.69 In other words, if you have them as a child, you will likely keep them as an adult. For example, a follow-up of the Harvard growth study of 1922-1935 showed that being overweight during adolescence was a greater predictor of chronic disease development (i.e., cardiovascular disease, CHD, arthritis) than being overweight as an adult.44 Likewise, aerobic fitness and physical activity behaviors tend to track into adulthood. Dennison et al.14 found that very inactive young adults had the lowest aerobic fitness scores (as measured by the 600 yard run) when they were youngsters. In Finland, a longitudinal study showed children who were most sedentary showed the least favorable cardiovascular disease risk profile when they became young adults.54

In adults, the relationship between physical activity and fitness, and their combined influence on cardiovascular disease risk is clear.7,19,47 In children, it is not known whether fitness or activity is the most important predictor for developing cardiovascular disease in adulthood.51,58,70 Also, there is no consensus on whether regular physical activity will result in significant gains in aerobic fitness in children, particularly those who are prepubescent.52 Significant associations between children=s level of physical activity and their fitness have been reported, 49,65 however the associations reported have been tenuous at best.43,49 It is possible that large variability in growth curves make it impossible to correlate the fitness and activity variables. Lack of a strong association between fitness and activity in children may also be attributed, at least in part, to methodological problems. Although a number of valid and objective tests of aerobic fitness have been developed, it is more difficult to quantitatively evaluate varying degrees of physical activity in youngsters.18,48,58 In any event, in a review of cross-sectional studies designed to measure children's activity levels, Sallis reported that boys were approximately 23% more active than girls; moreover, boys' activity levels declined 2.7% per year, while girls' declined 7.4% per year throughout adolescence.58

Physical inactivity in children may have a number of causes, ranging from poor self-efficacy for physical exercise to lack of space or equipment. Very young (4-7 year- old) children are much more likely to be physically active if their parents are active.41 This could possibly be due to a genetic predisposition to activity, but is more likely due to parents being role models and having the children share in family activities. Indeed, Klesges et al.26 showed that parents' actual participation in children's activities, rather than just "commanding" them to be active, was more related to the actual activity levels of the pre-school child. Family involvement appears to be a key to children's physical activity patterns.

Adolescents have perceived factors such as social time, use of drugs and alcohol, and lack of equipment as barriers to being physically active.64 Compared to boys, girls are less likely to include regular physical activity as part of their value system because it is not as well-accepted by their peers. Interestingly, it also appears teachers have a great effect on attitudes of children toward physical activity, and their influence appears stable throughout the middle-school years.20

Based on the significant relationship between aerobic fitness and all-cause mortality in adults,7 officials from the CDC recommended that schools take the lead and strive to make an impact on children's physical activity and fitness levels.28 The authors felt that schools offer a unique environment to make an impact in this area in that they can develop health-related activity and testing programs designed to promote appropriate exercise behaviors and accurately measure changes as they occur.

While not available in all schools, many programs have been developed that include greater emphasis on health-related physical activities and more class time for actual exercise participation. Guidelines have been developed for teachers and principals wishing to incorporate appropriate activities into their curricula.22,38,63

Even more innovative strategies have been introduced in virtually all grade levels.8,25,53,61 Interventions have typically been based on social learning theory where children or adolescents learn cooperatively, finding answers by exploring information provided by the teachers about proper nutrition, exercise and physical activity. These topics can be easily integrated into subject areas such as science, math, and language. Results have shown an increase in exercise self-efficacy and positive behavior changes. Common denominators for all these programs have included knowledgeable and cooperative teachers and administrators, and school districts firmly committed to the programs.


Potential Impact on the Citizens of Michigan

In terms of potential cardiovascular disease development, the risk profile of many Michigan citizens is very unfavorable. Our adult population is more likely to smoke, have elevated serum cholesterol, and have high blood pressure compared to the U.S. as a whole.39 In addition, 34% of Michigan adults are overweight - more than in any other state. The most prevalent risk factor in our state is physical inactivity - fully 56% of Michigan adults report being physically inactive.12 This last number is particularly sobering when its effect on health care costs is considered. It is estimated that 34.6% of CHD can be attributed to physical inactivity.11 Nationally, this translates to $5.7 billion in unnecessary health care costs from lack of physical activity.

When considering Michigan children, the risk profiles for chronic disease development are no better. Consider the following statistics:32

Given the association between physical activity habits and cardiovascular disease risk factor profiles, the impact of physical inactivity among children on the health of the citizens of Michigan is enormous.


Implications for Public Policy

The extreme importance of physical activity for health is understood now better than ever before, and yet all available evidence suggests that the future health of many Michigan children is being threatened every day by sedentary lifestyle habits. The stakes are too high for us to do nothing. We can and must develop policies that will save the lives of our children from preventible chronic disease. Children can learn to be active in three places - in their homes, in their communities via positive role models and concerned health care providers, and in their schools.

Private "Policies" Within Families

Probably the most important source of learning is from family members. Parents who do not engage in physical activity place their own health in jeopardy, but more importantly, miss an opportunity to be solid role models for their children. It is urged that all parents make family "policies" that include daily enjoyable physical activity for all family members.

Public Policies Within Local Communities

It is possible for local communities to make policies that can have a positive effect on children=s exercise opportunities. Communities are encouraged to develop and support programs that promote physical activities for children, including after-school programs, youth sports leagues, recreation centers, etc. Such programs which include quality adult supervision and role models, especially when held during the high-risk after-school hours and summers, can be expected to help prevent youth violence, crime, drug use, and teen pregnancy.

Public Policies Related to the Health Professions

Health and medical professions should join with educators and parents to give children a unified, clear message that physical activity is essential for health. Professional organizations representing physicians, nurses, dietitians, health educators, occupational therapists, physical therapists, etc., should offer continuing education for their members in the area of physical activity and health. Programs developed nationally such as the PACE Program to assist physicians in counseling clients on the importance of physical activity should be promoted in Michigan.

Public Policies Related to Schools

Despite the evidence that quality school physical activity programs not only promote physical fitness but also aid in cognition of other school subjects, Michigan has a long way to go in this area. The CDC has recommended that daily physical education programs be available for all grade levels,50 but Michigan has not adopted this mandate. In fact, fewer than one-third of students in grades 10-12 are enrolled in physical education classes.32

Simply designating school time for physical education is not enough. Classes must be structured so that the largest portion of time is spent in actual physical activities that involve all children, regardless of skill or fitness level. In Michigan , the average physical education class keeps the children active for less than twenty minutes.32

An important aspect of quality school physical education is skill development and enhancement of self-esteem through successful performance. Student who are "natural athletes" or who have had the benefit of adult help in learning sporting skills often participate most fully in physical education classes, while students with the greatest need of a habitual and rewarding physical activity program are often excluded from active competitions during physical education class.

This year, the CDC and the American College of Sports Medicine (ACSM) have published joint recommendations concerning physical activity.50 Regarding youth, the recommendations emphasize the importance of schools designing curricula for all children that are a) enjoyable, b) build self-efficacy related to exercise performance,

c) include significant amounts of physical activity and, d) involve a cognitive component that addresses lifelong fitness activities and habits. The policy recommendations for schools put forth at the beginning of this document are consistent with these recommendations and with the physical activity objectives from the document Healthy Children 2000, summarized in Appendix 1.


Summary

Michigan adults are not very successful, at present, in getting enough physical activity to maintain good health. Whereas some adults in the U.S. are exercising more vigorously than before, there has been no reduction in the number of individuals who are totally sedentary, and the incidence of overweight is increasing.37 It is difficult for adults to change long-standing sedentary lifestyle patterns. The exercise habits developed during childhood are likely to follow a person into adulthood. We can not afford a "wait and see" attitude with respect to our children's physical activity patterns.

Michigan has taken a positive lead in the nation in many areas affecting the health and economic well-being of its citizens. We must do the same in the area of chronic disease risk prevention by taking concrete steps to promote physical activity in all our children. Each parent, school, community, and health professional can have a positive influence on the physical activity of Michigan children.


Appendix 1

Summary of Physical Activity Objectives from Healthy Children 2,000

In the past ten years, several medical and scientific organizations have written opinion statements concerning physical activity for children.4,17,59 The most compelling guidelines are included in Healthy Children 2000, a set of goals and objectives for children's health written by the U.S. Department of Health and Human Services at the beginning of this decade.68 These guidelines were a subset of Healthy People 2000, which was written for all U.S. citizens. Under the category of physical activity and fitness are the following objectives:

Risk Reduction Objectives

1.3 Increase to at least 30 percent the proportion of people aged 6 and older who engage regularly, preferably daily, in light to moderate physical activity for at least 30 minutes per day.

Appropriate exercises include continuous rhythmic activities requiring involvement of large muscle groups. Examples are walking, swimming, skating, dancing, and children's active games. Light to moderate intensity in children/youth is equivalent to heart rates of approximately 100-120 beats per minute during the activity session.

1.4 Increase to at least 20 percent the proportion of people aged 18 and older and to at least 75 percent the proportion of children and adolescents aged 6 through 17 who engage in vigorous physical activity that promotes the development and maintenance of cardiorespiratory fitness 3 or more days per week for 20 or more minutes per occasion.

Activities that qualify for this category are similar to those previously mentioned. Vigorous exercise intensity is defined for most children/youth as a sustained heart rate of at least 120 beats per minute during continuous exercise sessions.

1.5 Reduce to no more than 15 percent the proportion of people aged 6 and older who engage in no leisure-time physical activity.

1.6 Increase to at least 40 percent the proportion of people aged 6 and older who regularly perform physical activities that enhance and maintain muscular strength, muscular endurance, and flexibility.

Engaging in a variety of physical activities involving many different muscle groups will help the individual maintain and develop muscular fitness. Flexibility improves with regular physical activity and may be enhanced even further when a youngster participates in a regular program of stretching exercises.

1.7 Increase to at least 50 percent the proportion of overweight people aged 12 and older who have adopted sound dietary practices combined with regular physical activity to attain an appropriate body weight.

Services and Protection Objectives

1.8 Increase to at least 50 percent the proportion of children and adolescents in first through twelfth grade who participate in daily school physical education.

1.9 Increase to at least 50 percent the proportion of school physical education class time that students spend being physically active, preferably engaged in lifetime physical activities.


References