- Our evolutionary history reveals that we need a certain level of physical activity as human beings
- Children all around the world are failing to meet guidelines for physical activity to the serious and long term detriment of their health
The American College of Sports Medicine (ACSM) defines physical activity as any bodily movement produced by the contraction of skeletal muscles that results in the substantial increase over resting energy expenditure. Being regularly physically active has been proven to reduce morbidity and mortality of chronic diseases in adults. In children suffering from cardiovascular risk factors such as obesity and diabetes, there is strong evidence that these conditions can stay with the child as they enter into adulthood. Therefore it is crucial that children are physically active to prevent the development of these chronic diseases later in adult life.
History of physical activity and our genes
The evolution of the human race and physical activity levels is best summed up by an exert from John Ratey’s book, Spark: The Revolutionary New Science of Exercise and the Brain (page 68). “Ten thousand years ago, everyone was a hunter gatherer, and life was marked by periods of intense physical activity followed by days of rest. It was feast or famine. By calculating how much our forebears “exercised” and comparing it to figures from today, it’s easy to see where the problem lies: Our average energy expenditure per unit of body mass is less than 38 percent of that of our Stone Age ancestors. And I think it is fair to say that our calorie intake has increased quite a bit.” (2)
Even in the last two decades the culture has changed - from safety issues such as allowing children outside by themselves and the freedom to go on adventures down to the creek for fishing or ‘exploring’, to the introduction of social networking and advanced computer games. Studies are now indicating that children of today are getting less physical activity and are less fit than children 20 years ago even though the risk of developing a cardiovascular risk factor has remained the same. (1)
Guidelines for physical activity
Currently the American College of Sports Medicine (ACSM), the World Health Organisation (WHO) and the Australian Institute of Health and Welfare (AIHW) all agree that children between the ages of 5-18 should be participating in at least 60 minutes of moderate to vigorous intensity physical activity every day. The 60 minutes does not need to be achieved all in the same session - bouts of 15 minutes to accumulate the 60 minutes is acceptable and most of this can be achieved from active play (link to article on active play).
It is also recommended by the Australian Institute of Health and Welfare (AIHW) that extended periods of no more than 2 hours of inactivity or 2 hours of accumulated electronic media or entertainment should be accumulated per day.
A national survey in 2004-2005 revealed that 19% of boys and 30% of girls aged between 15 and 17 years were doing none or very little exercise (National Survey 2004-2005).
On top of this, a Brisbane Study in primary schools during 2007 reported that approximately 21% of children aged 10-12 are not reaching the physical activity guidelines as stated by the AIHW (Table 1). And the trend seems global with a WHO 2005 report revealing that only 53% of 11 year old boys and 44% of 11 year old girls in European countries are reaching the recommended levels of physical activity.
In terms of the electronic media and entertainment guidelines, the same Brisbane study reported approximately 44% of 10-12 year olds are failing this guideline. As you can see it is no wonder there is an increase in cardiovascular risk factors in children and young adults.
Table 1. Brisbane Study on Primary school children in relation to physical
|Failing to reach
media guideline (%)
The parents' role in eliminating these statistics and helping children reach their guidelines is crucial. The amount of time a parent spends with their child a day compared with that of their teachers or the short time they see of their sports star on T.V. means that parents have the most contact and are thus the important models.
Parents' behaviour deeply effects the actions and behaviour of their children. Life today is very busy but for both the physical and psychological health of their children, parents need to prioritise active play time. This can be in the form of playing in the park with the dog, encouraging them to play a sport for a club or committing 30-60 minutes an afternoon to play backyard soccer or cricket. This way parents are able to spend quality time with their children, physical activity levels are being influenced which reduces the likelihood of developing cardiovascular risk factors, they are more likely to spend time playing the game with their friends and they are able to reap the benefits of motor skill learning during active play.
At the same time electronic media and entertainment is good for kids to relax and rest, however limiting their time spent using it is crucial. And it’s not just about banning them from T.V. or giving them 1 hour a night on the computer because kids need to fill their time. Instead, try and substitute an hour of TV or computer time for an hour of physical activity.
(1) Harsha, D. W. (1995). The Benefits of Physical Activity in Childhood. American Journal of the Medical Sciences, 310(6), p114
(2) Ratey, R. (2008) Spark: The Revolutionary New Science of Exercise and the Brain. New York: Hachette Book Group
(3) Spinks, A., Macpherson, A., Bain, C., McClure, R., (2007) Compliance with the Australian national physical activity guidelines for children: Relationship to overweight status. Journal of Science and Medicine in Sport, 10, 156—163