This is an excerpt from Enhancing Children's Cognition With Physical Activity Games by Phillip Tomporowski,Bryan McCullick & Caterina Pesce.
How Physical Activity and Exercise Enhance Children's Cognition
To understand how physical activity might affect cognition, it is important to have a general understanding of the structures and functions of the human brain and how those structures evolved. Many reflexive functions are controlled by brain systems that are evolutionarily very old; the brain structures involved in higher mental functions emerged relatively recently. The study of human evolution reveals that the physical activity of our early ancestors essentially guided the development of the modern human body and mind.
Our ancient ancestors faced life-threatening situations. To survive, they had to seek food, water, and shelter. Those who lacked the physical and mental skills essential to obtain these necessities perished. Brain size has been implicated as a crucial factor in the evolution of humans. The modern human brain consumes considerable energy - about 20 percent of the body's total energy production. Supplying the brain with the energy necessary to function efficiently led our ancestors to gradually alter their dietary intake and their behaviors. A hallmark accomplishment about 2.5 million years ago was the creation of tools that could be used to hunt and survive. The capacity to create and use tools requires complex cognitive and motor skills. Tools were made for specific tasks, and over time tool production became more sophisticated. As early humans migrated out of Africa, they learned not only how to deal with the immediate challenges of the environment, but also how to plan for future events. Survival depended on the ability to acquire and use knowledge about changes in terrain, weather patterns, sources of food and water, and shelter.
Over hundreds of thousands of years, the physical and mental characteristics seen in modern humans slowly changed. About 60,000 years ago, rapid changes in human cognition occurred. With language and the ability to think and reason, humans came to dominate the globe. Civilization emerged only 10,000 to 12,000 years ago, but within a short period of time, humans adapted to virtually every geographical area on the planet. In summary, the study of human evolution highlights the evolutionary role of physical activity and movement in the emergence of the brain structures responsible for complex cognitive and motor skills. The sections that follow address the link between physical activity and the development of brain and cognition across the life span and particularly during childhood.
Linking Physical Activity to Changes in the Brain
Although the brain is the center of thought and reasoning, relatively little was known about its structures until quite recently. Advances in technology and new tools over the past few decades revolutionized scientists' understanding of the brain and how it develops. Chapter 1 provided a brief description of brain development. Research conducted by neuroscientists over the past two decades has shed light on how physical activity and exercise may modify particular parts of the brain, which, in turn, alters the way children think and behave.
Four brain structures are likely to be influenced by physical activity - the cerebellum, motor cortex, prefrontal cortex, and hippocampus. As seen in figure 2.2, the cerebellum is a large brain structure that plays a key role in reflexive movement control and the fine-tuning of precise motor movement patterns. Recent research has shown that the cerebellum connects with every major brain structure and plays an important role in the control of movement and learning new skills. Studies conducted with animals have revealed that complex physical activity produces long-lasting structural adaptations in the cerebellum (Iacoboni, 2001).
Brain areas that change with physical activity: cerebellum, hippocampus, motor cortex, and prefrontal cortex.
cerebellum - An area of the brain that connects with every major brain structure and plays an important role in movement control and learning new skills.
motor cortex - A strip of brain tissue that sends commands to control muscles involved in movements.
prefrontal cortex - An area of the brain that consists of neural networks that make up the executive of the brain. It is involved in an awareness of current conditions, the retrieval of stored memories, and the formulation of action plans.
hippocampus - A structure located deep in the brain that plays a role in memory and learning.
Research conducted with laboratory animals, typically rats and mice, provides information about the effects of exercise that is not possible to obtain from humans. There is considerable support for the benefits of routine exercise on brain function in animals. Exercise leads to changes in neurons that control arousal and attention, increased levels of proteins that maintain brain health, the growth of new neurons in brain networks involved in learning and memory, and increased brain blood distribution (Hillman, Erickson, & Kramer, 2008).
Researchers who first showed that exercise causes improved cognition in humans were studying human aging. A number of studies conducted by Kramer and associates at the University of Illinois in the United States provided the first solid evidence that routine aerobic exercise increases older adults' executive functions (Kramer et al., 2002). Since then, experiments have linked exercise to alterations in brain structures and functions (Erickson & Kramer, 2009). More recently, these positive findings have been extended to younger adults and children (Krafft et al., 2014; Voss, Nagamatsu, Liu-Ambrose, & Kramer, 2011).
Linking Physical Activity to Children's Cognition
The ancient Greek philosopher Plato considered routine physical activity critical for children's education. His views have been supported by physicians and educators for centuries. However, until quite recently, relatively few studies considered whether and how physical activity influences children's thinking. Two general approaches have been used to study the effects of physical activity: one examines the effects of single bouts of acute exercise; the other examines chronic exercise training, which involves repeated bouts of exercise over several weeks, months, or years (Audiffren, 2009). Acute exercise produces temporary changes in children's physical arousal that affect thinking processes. Chronic exercise training produces structural changes in the brain and improvements in physical fitness. An understanding of the differences between the two approaches is important for appreciating the methods central to the physical activity games presented in later chapters.
acute exercise - Physical activity that produces temporary changes in children's physical arousal that affect thinking processes.
chronic exercise training - Repeated bouts of exercise over several weeks, months, or years that produce structural changes in the brain and improvements in physical fitness.
Both acute exercise and chronic exercise training benefit children's mental functioning - but in different ways. As children start moving, their heart and respiration rates increase; they become more aroused. Several studies have found that children's attention and learning improve immediately following physical activity that produces moderate levels of arousal (Tomporowski, 2003a). Studies highlight the importance of the nature of children's physical activity. Budde and colleagues (2008) found that a 10-minute bout of activity characterized by high demands on motor coordination control to mentally engage children improved their executive functions more than less demanding activity did. Similarly, Pesce and colleagues (Pesce et al., 2009) found that a 40-minute bout of a sport game led to better classroom learning than less mentally engaging aerobic exercise did. Although the type of activity and the duration of the bouts were quite different in the two studies, both showed that movement task complexity is an important factor. These findings are in direct opposition to the long-held view of many teachers that increases in children's arousal generated by recess and games interfere with academic classroom behavior and learning. In fact, the opposite is true. Physical activity, performed in the right way, may prepare, or prime, children to learn.
Also, physical fitness derived from habitual participation in physical activity seems to provide long-lasting benefits to cognitive functioning. Studies that compare physically fit and less physically fit children consistently show differences in brain structure and processing speed, which highlights the benefits of routine physical activity (Chaddock, Pontifex, Hillman, & Kramer, 2011).
The first experiment to clearly show that chronic exercise training improves children's mental function and alters brain function was conducted by Davis and colleagues (2011) at the Medical College of Georgia in the United States. They assigned overweight children randomly to a 20-minute or 40-minute exercise session, or to a nonintervention control group. Children in the exercise groups attended a 13-week after-school program in which they played games designed to maximize intermittent vigorous activity and to elicit high heart rate levels. The effects of the exercise programs on cognition were measured with a comprehensive test that provided measures of executive function, attention, spatial organization, and memory, and included a standardized test of academic achievement. The researchers discovered that exercise influenced specific measures of cognition and academic achievement.
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