Archive re-post - Healthy Body, Healthy Mind
27 Aug 2013
Healthy Body, Healthy Mind
1. Aim
To introduce research regarding how the body and mind are inextricably linked, focusing on the effects of exercise on brain development in humans.
2. Intended audience
The general public as it has far reaching consequences for us all. Despite an attempt to simplify the content, some understanding of basic biology and the nervous system will help. See terminology below.
3. Terminology
a. Neural plasticity - ability of the human brain to change as a result of one’s experiences.
b. Neurons - nerves.
c. Neurogenesis - development of nerve tissues.
d. Neurotransmitter - chemical substances which enable the nerve impulses to be passed from one nerve cell to the next.
e. Cognition - the mental process of knowing, including aspects such as awareness, perception, reasoning, and judgment.
4. Introduction
Mens sana in corpore sano, “a healthy mind, in a healthy body” (Juvenal 1st & 2nd AD, Roman Poet), “give me the child until he is seven and I will give you the man” (St Francis Xavier 1506 - 1552).
These two sayings have been used time and again over the centuries to mean many different things. However, I feel it is only now that their true relevance has been revealed. The relatively modern study of developmental psychology and its link to locomotion in the early phases of our lives is shedding new light on our evolution and enabling us to build strategies to combat an array of conditions. More importantly it is highlighting how we are neglecting what it is to be human; an animal that is designed to move and interact with our environment.
This blog is only the tip of the iceberg but touches on some of the key areas within this field of research and what it means for you and your children.
5. The basics
When you are born the brain is not a finished product. It is only about 20% complete[1]. All the neurons are there, however, they are unconnected. Over the next 3 years approximately 85% of this connecting takes place and is believed to be completed between 6-8 years of age [1],[2]. The way in which these neurons link however, is completely dependent on physical and emotional experiences during these formative years [1]. You can see in Fig 1, that the synaptic connections are at their most dense around the 2 year point and then actually thin out by the time you are an adult. This is because the body actually over produces synaptic connections in the early years as it lays down the foundations for later development [2]. Following this it plateaus and then proceeds to go through a phase of “synaptic pruning” around the age of 12 - 13yrs, where by the density of these connections decreases to around 60%[2]. In essence this streamlines the brain to ensure it works efficiently.
Fig 1. Showing how the brain “wires” itself in the early years
If the brain does not receive the correct stimulus in these formative years then it can have detrimental effects on the way in which the brain “wires” itself, see Fig 2. Now you may be saying to yourself “No @*%$ Sherlock, if you deprive a child of stimulus early on then you’re going to have problems” and quite right to. But it is not that simple;
· How much of a problem is it?
· How easy is it to neglect the correct stimulus?
· Can you re-wire the brain after these formative years?
· How we can we prevent it in the first place?
The research that has been most surprising are the effects of exercise on brain development. More and more studies are showing that it is physical activity in these formative years that actually lays down the pathways for learning and higher brain functions later in life and not early introduction of “academic” style learning. The brain and body link together to explore the environment around us, so physical activity promotes the growth of our brains in a variety of areas, not just the parts concerned with movement.
Fig 2. The neglected brain
6. Exercise and Early Neural Development.
At first there was some doubt as to the effects of exercise on the development of the brain, however, it is now widely accepted that physical activity does stimulate brain growth [2], helps to protect new neurons and improves cognition [3].
One theory put forward for the origin of this response to exercise is that it is possibly an adaptive process. In our hunter gatherer past it would certainly have been advantageous for us to engage our brains when we were foraging, i.e. improving our spatial memory and planning abilities [3]. Whatever the reason we know that our bodies and brains are designed to move through and engage with our environment. Not to sit at a desk all day and tap keys!
Studies have shown that by taking regular aerobic exercise, there are marked improvements in a child’s ability to perform in cognitive areas including perceptual skills, creativity and concentration, academic readiness, general achievement, IQ, maths and verbal tests [4]. This is supported by evidence gleaned in the classroom and in the laboratory, with neuroimaging evidence demonstrating that children with improved aerobic fitness have improved brain function and structure in general [5].
“The greatest cell proliferation in response to exercise occurs early in development, suggesting that exercise interventions may be particularly effective during early childhood” Halperin, et al (2012) [5]
Exercise or physical activity should therefore begin as early in life as possible in order to develop not only our bodies but more importantly our minds.
With regard to research on resistance training and brain function in children, there are no studies [5]. This is thought to be because of the common misbelief that children shouldn’t undertake resistance training. As such this area of study requires much attention.
7. Exercise and Adult Neural Development.
Unlike in children aerobic training has “a selective rather than general effect on task-related brain function” [5]. This is congruent with the fact that the adult brain has a lower degree of neural plasticity [6]. In general, aerobic activity increases brain structure, brain function and cognitive performance in elderly adults [5],[6]. The effects of resistance exercise on memory/cognition, is still very much open for debate, with some studies showing positive results and some not [5]. However, it has to be said that regardless of its effects on memory without a base level of strength (i.e. the strength to get out of a chair and confidently move around) you cannot achieve aerobic fitness anyway. As such my personal feeling is that both are important for total well being, although aerobic fitness, at present, is the most documented for prevention and treatment of decreasing cognitive abilities in older adults. It is important to note that stretching and toning does not improve brain function [6]. This is significant as a large swathe of older adults who do take exercise tend to conduct activities such as pilates and yoga (which are primarily stretching and toning based). As this is also the population most at risk from degenerative brain conditions, this is an area requiring some work from those involved in this research.
8. Conclusion
The importance of exercise in our lives has long been acknowledged but is generally seen in a slightly superficial way, namely to attain the “Body Beautiful” (what ever that is!!) or to improve only the performance of our bodies from the neck down.
To me this field of research highlights how critical physical education (P.E.), early parental engagement and exploration of the environment is for the development of our children, from the moment they arrive in this world. Instead the situation we have at present couldn’t be further from this. P.E. is being cut from school curriculums around the world, children spend more time in front of computers and infants are bought more and more “educational toys” rather than being encouraged to interact with the world around them. US statistics, for example, show that less than 50% of children aged 6-11yrs get the recommended 60min of exercise most days of the week and this figure only gets worse as they get older [5]. Then there are the societal pressures whereby parents are smothering their children in bubble wrap, so to speak, because they are either too scared of what might happen to them or too scared that other people will think they are bad parents when something does happen! The first 7 years of our children’s lives are vital to lay down the foundations of who they are and we must encourage them to interact with the environment and move their bodies in as many ways possible.
Fox, et al (2010) [8] sums it up nicely, “To borrow an analogy from economics, by investing early and well in our children’s development we increase the rate of return later in life, and in so doing improve not only the lives of individuals but of societies as well.”
In relation to the adult brain, the more we understand how to increase neural plasticity, the more we can help combat a host of degenerative conditions, improve recovery following trauma and aid conditions such as depression.
Little is known about whether or not exercise improves cognitive abilities and memory in “normal” young adults. Based on the research in this article however, I would hazard a guess that physical activity is vital in order to be a healthy, well-adjusted individual.
It truly is healthy body, healthy mind.
References
[1] Goodsport Trust Coaches Handbook, 2012. Early Development Movement p7-8
[2] Halperin J.M., Healey D.M.The Influences of Environmental Enrichment, Cognitive Enhancement, and Physical Exercise on Brain Development: Can we Alter the Developmental Trajectory of ADHD? Neurosci Biobehav Rev. 2011 January; 35(3): 621–634.
[3] Raichlen D.A., Polk J.D. Linking brains and brawn: exercise and the evolution of human neurobiology. Proc Biol Sci. 2013 January 7; 280(1750).
[4] Voss M.W., et al. Exercise, brain, and cognition across the life span J Appl Physiol. 2011 November; 111(5): 1505–1513.
[5] Halperin J.M., et al. Preventive Interventions for ADHD: A Neurodevelopmental Perspective. Neurotherapeutics. 2012 July; 9(3): 531–541
[6] Bavelier D., et al. Removing brakes on adult brain plasticity: from molecular to behavioral interventions. J Neurosci. 2010 November 10; 30(45): 14964–14971.
[7] Bryck R.L., Fisher P.A. Training the Brain: Practical Applications of Neural Plasticity From the Intersection of Cognitive Neuroscience, Developmental Psychology, and Prevention Science. Am Psychol. 2012 February; 67(2): 87–100.
[8] Fox S.E., et al. How the Timing and Quality of Early Experiences Influence the Development of Brain Architecture. Child Dev. 2010 Jan-Feb; 81(1): 28–40.
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