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The Dangers of Children Sitting Too Much
Improving Physical Health and Academic Performance through Everyday Awareness

Kaori Ishii
Associate Professor, Faculty of Sport Sciences, Waseda University

It has become clear that for adults, in addition to a lack of physical activity, sitting too much can lead to various health risks. For example, studies have shown that sitting too much while watching television, using computers, doing office work or commuting can increase the risks of obesity, excess body weight, diabetes and even death. How much time do we spend on activities done while sitting? Many of us are often unaware of it. If we look back on our daily habits, we will realize that we spend a considerable amount of time sitting. In recent years, it has been reported that the problem of sitting too much is affecting not only adults, but children as well. It is also being reported that the habit of sitting too during childhood years can carry over into adulthood [1]. Therefore, it is important to eliminate children’s habit of sitting too much to promote a healthy adult life.

The Impact That Sitting Too Much Has on Children

In recent years, studies have shown that the length of time children spend sitting is related to various health risks [2], [3]. It is now known that children who watch more than two hours of television a day have higher risks of obesity and excess body weight, and increased screen time (time spent watching television/DVDs, using computers, playing video games, etc.) is linked to higher risks of cardiovascular disease, metabolic syndrome and other health risks. Furthermore, studies have shown that reduced sitting time can improve physical health.

Sitting too much not only affects our physical well-being, but also our mental health. It has been shown that sitting too much while watching television or playing video games is linked to low quality of life, problematic behavior, depression and other mental health issues. For example, according to a study that used children and students in Japan as subjects, it has been shown that the length of time spent sitting is linked to poor mental health. In addition, changes in physical activities outside of school and changes in activities done while sitting during holidays in a span of two years can impact mental health two years down the road [4], [5]. Furthermore, it has been reported that regarding the use of media devices such as televisions, video games and computers, using two or more devices for over an hour a day makes children more susceptible to depression [6].

It has been shown in recent years that sitting too much can even affect academic performance. It is now a widely accepted fact that watching television and DVDs, using computers and playing video games for more than two hours a day can lead to poor academic performance. At more than three hours a day, it has been shown that it can even lead to lower IQ scores [2].

In the past, the importance of exercise and other physical activities has been emphasized for maintaining and improving children's mental and physical health, but trying to enforce such behavioral changes can be a difficult challenge. It is of course necessary to spend more time being physically active, but first and foremost, we must reduce the amount of time spent on activities while sitting. By simply ceasing to engage in some of our regular activities, we can expect an improvement in the mental and physical health, and academic performance of children without taking on such a difficult challenge.

The Realities of Children Sitting Too Much

In other countries, it is recommended that children spend less than two hours of screen time a day in order to reduce the amount of time they spend on sitting [7]. However, the rates of children who actually meet these standards in those countries are only about 30 to 50 percent. In Japan, the rates are 35.5 percent for boys and 40.7 percent [8] for girls, which are similar to other countries. Over half of all children do not meet the standards. According to the results of a study [8] that examined what activities children do while sitting and how much time they spend doing them, it was shown that elementary school students on weekdays spend a weekly average of 90 minutes reading or listening to music, 535 minutes watching television or videos, 167 minutes playing video games, 24 minutes using computers, 265 minutes doing homework, and 33 minutes sitting in cars.

By examining the lives of the children around us, it is clear that they spend a considerable amount of time sitting. For example, most of the time spent in school is spent sitting, and even in physical education classes where intensive physical activity is expected, elements in physical education leaves much time for some children to be sitting while other children are active, or sitting while listening to the teacher speak. In other countries, it has even been pointed out that 70 percent of the time spent in physical education classes is spent sitting. Taking these realities into consideration, it can be said that measures to prevent children from sitting too much is a matter of great importance.

To Reduce the Amount of Time Children Spend Sitting

Research done in recent years has shown that one of the important causes that impacts the amount of time children spend sitting has to do with the environment surrounding the individual. In order to encourage a better environment, one example is the schools that are systematically changing school policy to provide programs that promote more physical activities, while at the same time providing sports or physical activity equipment such as balls and jump ropes. Some schools are also adjusting the number of children who spend time outdoors at one time in order to reduce density, and are increasing recess hours. They are also changing schoolyards to grass lawns [9]. In Japan, efforts are being made to focus more on the equipment provided by school [10]. In these efforts, studies are being conducted to examine the difference in time spent sitting during recess breaks (slightly extended break period between second and third period) and lunch hours between schools provided with physical activity equipment that can be used freely during each class, and schools that were not provided such equipment. As a result, it has been reported that students in schools that were provided with supplies spent less time sitting during both recess and lunch breaks (figure below).

Figure: Difference in time spent on sitting activities between schools provided with physical activity equipment and schools that were not (minutes/day)
Source: Reference 10

In Japan, efforts to impact these environmental factors have only just begun, and it is anticipated that further research will be accumulated. However, there are several things that can be done right away. For example, we can begin by having children stand while performing tasks that do not require sitting, encouraging them to go outside during recess hours and providing classroom lectures on the health effects of sitting too much to increase awareness among the children themselves. I also think it would be effective for parents and guardians to gain a better understanding of the negative effects that sitting too much can have on their children in order to increase awareness on this issue in their daily lives. Through these efforts to impact the environmental factors that accommodate the living space of children, as well as efforts made by the adults surrounding them, children will spend less time sitting, and as a result, we can expect improvements in their physical and mental health, physical strength and academic performance.

  • ^Biddle SJ, Pearson N, Ross GM, Braithwaite R. Tracking of sedentary behaviours of young people: a systematic review. Prev Med. 2010, 51(5), 345-351.
  • ^Tremblay MS, LeBlanc AG, Kho ME, Saunders TJ, Larouche R, Colley RC, Goldfield G, Connor Gorber S. Systematic review of sedentary behaviour and health indicators in school-aged children and youth. Int J Behav Nutr Phys Act. 2011, 8, 98.
  • ^Carson V, Hunter S, Kuzik N, Gray CE, Poitras VJ, Chaput JP, Saunders TJ, Katzmarzyk PT, Okely AD, Connor Gorber S, Kho ME, Sampson M, Lee H, Tremblay MS. Systematic review of sedentary behaviour and health indicators in school-aged children and youth: an update. Appl Physiol Nutr Metab. 2016, 41(6 Suppl 3), S240-265.
  • ^Ishii K, Shibata A, Adachi M, Mano Y, Oka K. Objectively Measured Sedentary Behavior, Obesity, and Psychological Well-Being: A Cross-Sectional Study of Japanese Schoolchildren. J Phys Act Health. 2017, 14(4), 270-274.
  • ^Ishii K, Shibata A, Adachi M, Oka K. Association of physical activity and sedentary behavior with psychological well-being among Japanese children: a two-year longitudinal study. Percept Mot Skills. 2016, 123(2), 445-459.
  • ^Nakamura H, Ohara K, Kouda K, Fujita Y, Mase T, Miyawaki C, Okita Y, Ishikawa T. Combined influence of media use on subjective health in elementary school children in Japan: a population-based study. BMC Public Health. 2012, 12, 432.
  • ^American Academy of Pediatrics. Committee on Public Education. American Academy of Pediatrics: Children, adolescents, and television. Pediatrics. 2011, 107, 423-426.
  • ^Ishii K, Shibata A, Adachi M, Mano Y, Oka K. School grade and sex differences in domain-specific sedentary behaviors among Japanese elementary school children: A cross-sectional study. BMC Public Health. 2017, 17, 1, 318.
  • ^Ishii K. Interventions focused on the physical activity environment to reduce sedentary behaviors among children: A systematic review. Japanese Journal of Physical Fitness and Sports Medicine. 2016, 65(4), 357-366.
  • ^Ishii K, Takahashi R, Aoyagi K, Mano Y, Oka K. The effects of providing equipment for promoting physical activity in recess among Japanese elementary school children. Japanese Society of Health Education and Promotion. 2015, 23(4), 299-306.

Kaori Ishii
Associate Professor, Faculty of Sport Sciences, Waseda University

[Career history, published works, etc.]
Kaori Ishii is an associate professor at the Faculty of Sport Sciences, Waseda University. She has a Ph.D. in medicine. She is an expert in the study of physical growth and development, as well as health education. She completed the course at Tokyo Medical University Department of Preventive Medicine and Public Health. Before assuming her current post, she was a research associate, then an assistant professor at the Waseda University Faculty of Sport Sciences. The focus of her research is on promoting physical activities with the aim of improving the health of Japanese people.