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Part I
Progress and possibilities
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Chapter 1
Physical activity and educational achievement
Dose–response relationships
Erin K. Howie and Russell R. Pate
Introduction
Mens sana in corpore sano (a sound mind in a sound body). Physical health and fitness have long been thought to benefit thinking and mental health. But how much physical activity do we need for a sound mind? This chapter gives an overview of the dose–response relationship between physical activity and educational achievement. It begins with definitions of key concepts followed by a brief history of the relationship between learning and movement. It then describes the dose–response as it relates to time, intensity and type. The chapter concludes with a summary and practical implications for educators.
Definitions and concepts
Physical activity (the dose)
Physical activity is bodily movement produced by muscle contractions that raise energy expenditure above resting levels (Caspersen, Powell, & Christenson, 1985). For the purposes of this chapter, which examines the effects of physical activity on educational outcomes, two subcategories of physical activity are specified:
1 acute physical activity – a single session of physical activity, e.g. 20 minutes of walking on the treadmill or 40 minutes of a physical education class;
2 regular physical activity (or training) – physical activity (or training) that is performed multiple times over a period of days, weeks, months or years, e.g. 30 minutes of recess every day for one school year or 8 weeks of an afterschool exercise training programme.
Moderate-to-vigorous physical activity is a specific intensity level of physical activity that is more than three times the amount of energy used while resting. This type of physical activity has been shown to be beneficial for cardiovascular health. Examples of moderate-to-vigorous physical activity include brisk walking (that makes you start to breathe heavily), running, jumping and dancing.
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Physical fitness is a set of characteristics related to health or skills, such as aerobic capacity or muscular strength (Caspersen et al., 1985). While physical fitness is likely to be related to educational outcomes it will not be discussed in this chapter, as it is a health characteristic that is influenced but not determined by the behaviour of physical activity.
It is important to describe accurately in detail the dose or exposure when considering the relationship between physical activity and educational outcomes. Often times, a cross-sectional study will show that there is a positive relationship between physical fitness and educational outcomes. The media then interprets it into an article, ‘Exercise makes you smart’, when in reality there are many factors that contribute to physical fitness (including physiology).
Educational achievement (the outcome)
Educators and researchers have examined a wide variety of educational outcomes. Three different types of educational outcomes are described below and depicted in Figure 1.1.
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Brain structure and functions
Physical structures and physiological processes underlie all thought processes. Brain functions can include the anatomy of specific brain structures, such as the size of the hippocampus, or electrical activity measured through electroencephalogram (EEG) to examine the activity of certain areas of the brain (Khan & Hillman, 2014). Many of the tests used to measure brain structure / function may also measure cognitive functions. For example, EEG or functional imaging may be used during the flanker task, which measures executive functions; such combinations are neurocognitive outcomes.
Cognitive functions
Cognitive functions, or mental actions, are the result of the underlying brain functions and consist of several cognitive processes, including attention, memory and problem solving (Aukrust, 2011). One example of a commonly used measure is the d2 test of attention. Many studies have examined executive functions or high-level, complex cognitive processes which control other processes. Executive functions include cognitive flexibility or shifting, working memory and inhibition (Miyake et al., 2000). Executive functions can be assessed through tests such as flanker tasks, the Stroop test (Chan, Shum, Toulopoulou, & Chen, 2008) or batteries such as the Delis-Kaplan Executive Function System.
Academic achievement
The most relevant category of educational outcomes for educators is academic achievement. Measures of academic achievement include standardized batteries, such as the Stanford Achievement test or Wide Range Achievement Test; school grades; or scores on standardized tests such as school- or state-level achievement tests.
It is important to note that brain structure and functions, cognitive functions and academic achievement all interact in multiple ways. For example, improved brain activation in the frontal cortex may lead to improved performance on an executive function cognitive task, which may lead to better maths performance on a standardized test. Similarly, improved inhibition on a cognitive task may relate to improved on-task behaviour in the classroom and ultimately better school grades. In the education literature, it has long been debated if time-on-task directly relates to academic achievement outcomes such as performance on standardized tests (Karweit, 1984).
As well as accurately describing and defining physical activity, it is important to describe the educational outcome of interest. The same cross-sectional study that showed that there was a positive relationship between physical fitness and educational outcomes may have examined electrical activity in the brain during a specific task. The article reports ‘Exercise makes you smart’; however, brain activity during a single task does not mean that child had higher intelligence or will do better in school. It is essential to take a critical view when reading and interpreting research studies.
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Dose
The dose of physical activity is the amount of physical activity that a child receives. This is composed of the frequency (when considering multiple sessions of regular physical activity), intensity (light or moderate-to-vigorous physical activity), and time (how long is/are the session(s)). A description of the dose can also include the type of activity. In traditional exercise prescription, dose may refer to aerobic activity, muscular strength training or flexibility exercises. The majority of studies about the relationship between physical activity and educational outcomes have examined aerobic physical activity. But within aerobic exercises, the type of activity has varied from skills-based physical education, to walking on a treadmill, to physical activity that is integrated with learning activities also known as active lessons.
Dose–response relationship
This term refers to the varying response in an outcome as the result of varying exposures or treatments. Studies of the dose–response of physical activity on educational outcomes could examine the effect of different durations, differing intensities or different types of physical activity. For example, 10 minutes per day of regular physical activity may result in an increased test score of 10 points on a 100-point scale. However, 20 minutes per day may result in an increased test score of 20 points.
History of physical activity in education
Physical activity has long been considered an important part of overall mental health and intellectual capacity.
In early Greece, excellence in both mind and body were prized (Van Dalen, 1953, p. 35). The Athenians integrated physical education into society as a way to develop the mind through the physical (Van Dalen, 1953, p. 47). Many Greek philosophers supported incorporating physical activity in daily life. One quote that has been attributed to Socrates states:
(Van Dalen, 1953, p. 61)
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The now common phrase of the Roman poet Juvenal, mens sana in corpore sano, again emphasized the connection between mental and physical translated into ‘a sound mind in a sound body’.
From the early middle ages of the fifth to tenth centuries, when education was controlled by the Church, physical education was included in the curriculum as part of the training to be a functional and valued member of society. Later, in the 14th and 15th centuries, sport and activity were considered critical parts of a humanistic and holistic education (Zeigler, 1967). In the late 17th century, the influential educational philosopher John Locke, who was trained in medicine, opened his work ‘Some thoughts concerning education’ with the words, ‘A sound mind in a sound body, is a short, but full description of a happy state in this world’ (Glassford & Redmond, 1967). This shows how educators valued physical health.
Physical activity became more formalized during the 19th century. ‘Rational recreation’ or the belief that exercise refreshed the mind and body for society and work was promoted by middle- and upper-class Victorians (Rader, 2004). The Greek Olympics was revived in its modern form at the end of the century as a way to promote peaceful competition and national pride (Rader, 2004). John Dewey led educational reforms advocating for formal physical education in schools. Dewey believed in ‘education though the physical’ (Barney, 1967). By 1967, physical education was a required subject in 72 out of 73 countries studied by the International Council for Health, Physical Education and Recreation (Glassford & Redmond, 1967). The World-wide Survey of School Physical Education of 2013 confirms that 97% of countries have a physical education requirement; however, these policies are often not carried out in practice (United Nations Educational Scientific and Cultural Organization (UNESCO), 2014).
Physical education has thus become a pillar of children’s education around the world (Van Dalen, 1953). In addition to traditional physical education, physical activity has been incorporated into the modern school day through other opportunities such as recess, school sports) both extra- and intra-mural), music and dance, and classroom activity breaks. However, with increasing pressure from high-stakes standardized tests, school teachers and administrators are cutting time for physical activities in favour of core subjects (Center on Education Policy, 2011). Decreasing physical activity time may have unintended consequences; emerging research suggests that physical activity promotes learning, as highlighted throughout the chapters in this book. Thus, an understanding of the optimal dose to benefit educational outcomes is needed for educators to incorporate and maintain physical activity in schools.
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Review of the evidence on the dose–response of physical activity and academic outcomes
Research on the educational effects of physical activity has been ongoing since the mid 20th century, and the number of studies published each year is increasing exponentially. A key study in France in the 1950s examined the effects of increasing physical education from 8% to 22% of the school day on standardized test performance. After 20 years, schools with increased physical education performed better on French national examinations (Glassford & Redmond, 1967). A review conducted in 2012 located 125 published studies on the topic (Howie & Pate, 2012). While the majority of studies found a positive relationship between physical activity and improved educational outcomes, most of the studies were of low quality and used cross-sectional designs. In addition, studies used varied doses of physical activity exposures and measures of educational outcomes, making comparisons across studies difficult.
This chapter provides a summary of the research to date on the dose–response effect of physical activity on educational outcomes. Because experimental and quasi-experimental research designs provide the best understanding of the causal relationship between physical activity and educational outcomes, this chapter will focus on those types of experimental studies and will not include cross-sectional or longitudinal studies.
For this chapter, a narrative review was conducted. The selection of articles began with the studies identified in the previous review (Howie & Pate, 2012). Thirty additional relevant experimental studies were identified from the literature, in addition to the 66 experimental studies identified in the previous review.
Articles were summarized by three components of dose, as described in an earlier section: time (duration and frequency), intensity and type. Articles were grouped by those looking at the effects of acute physical activity or regular physical activity. Ideally, one could combine the duration, frequency and intensity of physical activity to create a single metric of the exposure dose (i.e. total amount of energy expended). However, due to inconsistencies in reporting it was not possible to compute a single metric.
Time (duration and frequency)
Acute studies
Studies that have examined the effects of a single bout of physical activity on educational outcomes (brain structure and functions, cognitive functions and academic achievement) have varied in duration from 1 minute to 60 minutes of physical activity. Most of the acute studies have examined brain functions, cognitive functions and on-task behaviour. This section will summarize studies that have examined 10 minutes or less of acute physical activity, 11–20 minutes of physical activity, 21–30 minutes of physical activity and greater than 30 minutes of physical activity.
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SHORTER BOUTS OF ≤10 MINUTES
Few studies have examined the effects of shorte...