There is an increasing need to get adults and kids active now, more than ever.
The world is currently faced with an obesity epidemic amongst our children and adults. The main cause for this epidemic is the sedentary lifestyle many people live. Not only is this lifestyle detrimental to human health but there is also a link between exercise and the improvement in the development and longevity of the brain and its cells. Research has investigated the effect of physical activity on the brain ranging from studies of mice living in enriched environments to cognitive performances such as, verbal and mathematical tests, memory, and developmental level of children. Studies have also been looking at the structure of human brains with Magnetic Resonance Imaging (MRI), and the level of vascular endothelial growth factor(VEGF), insulin-like growth factor 1 (IGF1), and brain-derived neurotrophic factor (BDNF) in a person’s blood. There has been lots of research done in recent years that has advanced our knowledge and given us a better understanding of how exercise affects the cognitive ability in people.
There is a correlation regarding physical fitness and the cognitive development of the brain. There is increasing amounts of evidence that suggest physical fitness changes the structure and connection within the brain. Exercise plays a key role in plasticity and various supporting systems that aid in maintaining the health and functions of the brain.
It used to be believed that the brain was a unchangeable organ but with CAT scanning, MRI and other imaging technologies we now know the brain can be rewired and reshaped, with changes in lifestyle, this is called neuroplasticity. The main growth factors that participate in modulating the functions of the brain are vascular endothelial growth factor(VEGF), insulin-like growth factor 1 (IGF1), and brain-derived neurotrophic factor (BDNF). VEGF is a growth factor that prominently involved in the formation and development of blood vessels.
Therefore when exercise increases the presences of VEGF there is a increase in blood vessels in the brain which leads to a greater development and increased size of the brain. These new blood vessels are utilized to supply the increased demand for nutrients in the brain. IGF1 is a growth hormone that regulated VEGF, in addition to this the IGF-1 gene’s presence is increased in hippocampal neurons in response to exercise, occurring for several days post workout (Hillman, & Erickson, & Kramer, 2008)).
Improved memory and increases neurogenesis is seen to be strongly related to the increase of peripheral IGF1, caused in response to the exercise. When looking at exercise induced IGF-1 level the researchers; Lopez-Lopez, LeRoith, and Torres-Aleman “examined exercise-induced angiogenesis in mice that had normal levels of IGF-I in the brain….Normal mice showed enhanced proliferation of brain endothelial cells (line blood vessels) after physical exercise.
For instance, in the cerebellar cortex, the total number of cells increased from about 199 cells to about 285 cells within a volume of 1mm3 in response to one month of exercise.”(Lopez-Lopez, & LeRoith, & Torres-Aleman, 2004). BDNF promotes new growth and the survival of existing neurons, it is also related to long-term memory formation. BDNF concentrations are increased after acute exercise regimes(cotman, & Berchtold, & Christie, 2007). This is important because the concentration of BDNF is lower in patients who suffer from alzheimer’s,parkinson’s, depression, anorexia, and many other diseases. With exercise increasing the presence of these molecules, it has a neuroprotective effect on the brain, reducing injury, such as with a stroke, and delays the onset of several neurodegenerative diseases.Neuroimaging has the ability to look at the effects of physical activity on the brain physically in humans, by using Magnetic Resonance Imaging (MRI), electroencephalograms(EEGs). EEG’s use sensors placed onto the scalp of the participant, to detect the frequencies of their brain waves.
There has been lots of research that has looked at the changes in how the brain waves are used when comparing less aerobically fit individuals to individuals who are aerobically fit. Brainwaves are produced by electrical pulses from a large amount of neurons comunicating with each other, and change epending on what a person is doing, and how they are feeling. “Examination of baseline spectral frequency distributions brainwave frequency of EEGs has revealed increased activation in the theta related to learning, memory, and intuition., alpha aid in overall mental coordination, calmness, alertness, mind/body integration and learning, beta present when a person is alert, attentive, engaged in a problem solving, decision making, or any focused mental activity spectral bands, and higher mean frequency in the delta,theta, and beta bands in more active or aerobically fit individuals.”(Hillman, etal 2008). These findings reveal that physical activity has an effect on baseline electrocortical function. This is further supported by the finding that P3, a waveform that can be used to measure how demanding a task is on cognitive workload, is connected to the the spectral frequency activations.
There has also been a correlation between cognitive impairment and modifications in the P3 (Polich, 2007). When aerobically fit individuals are compared to their less fit peers ,during a range of cognitive task,the aerobically fit individuals had a larger amplitude and shorter latency P3. These findings have revealed a connection between aerobic fitness and the improvement of cognitive processes such as faster stimulus encoding.
A MRI is another neuroimaging tool used to look at the effects of physical activity on the brain and cognitive processes. A larger volume of prefrontal and temporal grey matter, and anterior white matter can be directed to individuals with higher levels of fitness, when reviewing a cross sectional comparison between individuals with low and high fitness levels. “Older adults who participated in a walking intervention over a 6-month period showed increase in activation in the middle frontal gyrus and superior parietal cortex and decreases in activation in the ACC, relative to a non-aerobic toning and stretching control group”(Hillman, etal 2008)There has been little to no reliable sources of tests done on physical activity and the level of achievement during performance type testing. Benjamin Sibley and Jennifer Etnier did a meta analysis, where they collected data from as many studies they found with reliable, relevant data, looking at the effect of physical activity on test scores.
The tests scores that were reviewed were divided into eight groups; perceptual skills, intelligence quotient, achievement, verbal tests, mathematic tests, memory, development level/academic readiness and other. “This review suggest that physical activity has a positive relationship with cognition across all design types, for all participants, and for all types of physical activity”(Sibley, & Etnier, 2003)Non human animal research, many performed with rats, has allowed researchers to observe exactly the effect of physical activity on the cellular and molecular signal pathways, which can only be presumed in humans. Non human studies also gives researchers more control regarding the diet, lifestyle factors, and social interaction amongst their test subjects. One of the most consistently observed effects of exercise treatment is an increase in cell proliferation and cell survival in the dentate gyrus of the hippocampus.(Hillman, etal 2008). This effect of cell proliferation and survival was observed at all ages even in newborn rat pups who had mothers that participated in aerobic exercise during pregnancy. The researchers had also observed behavioural performance improvements that were associated with the new cells produced, therefore these cells might promote learning and memory. The increase of cells in the brain demand more nutrients which is where the vascular endothelial growth factor(VEGF), insulin-like growth factor 1 (IGF1), and brain-derived neurotrophic factor (BDNF) respond.
VEGF, IGF1, produce the needed blood vessels to deliver the needed nutrients. The BDNF is also increased after an acute exercise regime, increased levels of BDNF have shown enhanced learning and memory processes. With this non human animal research we gain new insights and knowledge regarding the human connection between physical activity and cognitive improvement. Most if not all research that has been done has seen a positive correlation between physical fitness and the development or growth of the brain. Researchers have seen an increase in levels of vascular endothelial growth factor(VEGF), insulin-like growth factor 1 (IGF1), and brain-derived neurotrophic factor (BDNF) which cause new blood vessels to form. These new blood vessels provide the nutrients to the elevated amount of brain cells, which enhance learning and memory. There has been a large number of positive neuroimaging images that correlate with the belief that exercise improves the brain’s development.
This positive correlation is also seen in the little data we have on performance based test between exercise and improved scores. The animal research done has only proven the believed benefits of physical activity on the brain and this form of research has given answers not available with humans. Daily physical activity in childhood could be a necessity for the developing brain. “Children at play tend have more spontaneity and less interest in sustaining a single activity.
These differences may result from differing needs of the developing brain to provide itself, through activity, with a pattern of varied stimulation from the environment that subserves its own optimal development.”(Burdette, 2005). Encouraging and increasing daily physical activity in kids will not only improve their health physically but it will also help them cognitively developed.
The lifestyle of an individual during childhood will usually follow them throughout their lives.