Abstract The effect of exercise onphysical health is well documented. What is less studied, but by no means lesssignificant, is the relationship between exercise, cognition and neurologicalhealth. Physical exercise has been found to improve executive function throughthe stimulation of the anterior cingulate cortex. Additionally, physicalexercise causes cognitive processing during stimulus encoding to occur faster. Thisis due to larger amplitude and shorter latency P300 components.
Therelationship between exercise and cognition could be used as a treatment forAlzheimer’s disease and Schizophrenia. In Alzheimer’s disease an increasedlevel of physical fitness has been found to reduce the amyloid load, decrease ??deposits, up regulate the levels of Nepresprin and increase hippocampalfunctioning due to an increase in the secretion of brain-derived neurotropicfactor. In patients with Schizophrenia exercise has increased the hippocampalvolume, changed the cortical thickness and increased secretion of brain-derivedneurotropic factor.
The relationship between aerobic fitness and academicperformance in children was also examined, with the trend being that childrenwho are more aerobically fit score higher on mathematics and reading tests. Itis postulated that the frontopariteal network is linked to both cognition andexercise. When used in conjunction with other forms of treatment exercise hasthe capacity to improve the symptoms of various neurological diseases, andhealthcare policy should be updated to reflect this. Introduction We all know that exercise iskey to a healthy lifestyle, but could exercise improve your neurological health?In recent years, there has been an increase of interest in studying the relationshipbetween exercise and cognition. This relationship becomes increasingly importantwhen studied in conjunction with a variety of neurological disorders.
Thepotential for exercise to reduce the risk of developing age associated neurodegenerativedisorders, such as Alzheimer’s disease and vascular dementia (Paillard 2015), is an important area. It has alsobeen shown that regular exercise can help improve the clinical symptoms ofpatients with psychological conditions such as Schizophrenia (Nuechterlein 2016). The effect of exercise on the cognitionand academic performance of children is also an interesting area of research,many school teachers will tell you that children perform better academicallyafter a break from their schoolwork, but is there a scientific explanation forthis? Whilst the molecular mechanisms for these effects are relatively unknown,some progress has been made in understanding the structural alterations to thebrain during exercise that have an effect on cognition. Effectsof exercise on the human brain Physical exercise has thecapacity to improve cognition, specially, it has been found to improveexecutive control processes. Thereforeit follows that brain structures that are involved in executive control arelikely to be altered by physical exercise. The anterior cingulate cortex (ACC),which is a part of the limbic system, is one such region.
Physical activity hasa significant effect on the ACC. Neuroimaging studies that focused on theeffect of changes in aerobic fitness and the ACC found that adults that had partakenin an exercise program showed a decrease in behavioral conflict when performinga task that required differing levels of executive control, when comparedagainst untrained participants. This supports the view that higher levels of physicalactivity are associated with increased top down control, mediated through theACC, resulting in increased performance of tasks that require high levels ofexecutive control. (Hillman 2008). Furthermore, aerobic fitnessalso appears to have a relationship with the P3 component. The P3 component isthought to be generated by a network of neural structures (including the ACC) thathas a role in cognition.
Specifically these neural structures have roles instimulus updating and memory processing. (Polich2004). Multiple studies have found that largeramplitude and shorter latency P3s are found in individuals with higher levels of aerobicfitness. This suggests, that a high level of aerobic fitness is beneficial in cognitiveprocessing. In particular, processing that is involved in the allocation of attentionalresources and faster cognitive processing during stimulus encoding (Hillman 2008). Alzheimer’sdisease and exercise By2050 the number of people living with Alzheimer’s disease (AD) in the UnitedStates is projected to increase by 10million (Alzheimer’sA 2015). This is a trend that is reflected worldwide, partly due to thefact that people are living longer, emphasizing an already pressing need to understand and develop: novel treatments,preventative measures and changes in healthcare policy for AD. Encouragingpatients who are likely to develop AD or other age associated neurodegenerativedisorders to engage in regular physical exercise could be a way of reducing theirrisk of developing these diseases.
This is because physical exercise has thecapacity to prevent age related cognitive decline (Bhreer2013). It has been shown that as you get older, if you increase (ormaintain) your cognitive function you reduce the risk for devolving ageassociated neurodegenerative disorders (Hilman). Highlightinga use for so called “prescribed exercise” as a preventativemeasure to lower the risk of developing AD.
The aggregation of Amyloid ?-peptide (??) plaques incerebellum is a key event in AD Pathogensis (Fig one). The rest of the diseasesprocesses, including TAU tangle formation, is a result of an imbalance of ??production and clearance. (Hardy 2002). It hasbeen shown in animal models that regular exercise reduces the amyloid load (Adlard 2005). A 2005 study in mice found thatregular voluntary exercise significantly decreases the ?? load, and thatexercise could be a simple behavioral change to prevent or slow the developmentof AD. Another study, again in mouse models, shows that an increase in exerciseleads to a decrease in cerebral ?? peptides and amyloid deposits in vivio.
Additionally,in this study the animals that had increased levels of exercise also showeddifferences in gene expression. For example, the activity of Neprilysin (NEP), a compound that degrades amyloid, is upregulated in the brains of these mice (Karsten 2005). In addition to accumulation of??, AD causes changes in the brain structure- such as loss of cortical neuronsand loss of connections between brain systems (Dennis2014). Additionally in AD, there is severe atrophy in the hippocampus.The hippocampus is involved in episodic memory, which can be defined as theability to recall memory’s from ones past in context (LaJoie 2014). Physical exercise has the capacity to improve hippocampal function;this is done by the increase of secretion of a molecule known as BDNF (brain-derivedneurotropic factor) during exercise (Intlekofer 2013). BDNF, along with additionalgrowth factors, promotes the processes of neurogenesis, angiogenesis andsynaptic plasticity. Physical activity has also been shown to preservehippocampal volume in elderly people with a high genetic risk of developing AD (Smith 2014).
Whilst this is an emergingarea of research, it highlights the potential for exercise to improve the cognition,and potentially reduce the risk of developing AD. Therefore, encouraging peoplewho have a high risk of developing AD is something that should be considered inHealthcare policy. Exerciseand Schizophrenia Schizophreniais a psychological condition which affects 1 in 100people. The clinical symptoms of Schizophrenia include hallucinations,delusions and disorganized behavior. Cognitive impairment is another symptom ofschizophrenia, specifically in executive function (Elliot2003). This makes behaviors such as planning and reasoning difficult,reducing the patient’s quality of life. As exercise has previously been shownto improve cognition (and specifically executive function) in healthy individualsit stands to reason that exercise may have the capacity to improve thecognition in individuals with Schizophrenia. The use of exercise as a form of treatment for individualswith Schizophrenia becomes increasingly important when you consider that, formany patients, cognitive behavioral therapy and Pharmacotherapy have alreadybeen tried, and both may have unpleasant side effects making the treatmentsomewhat redundant (Revvel 2015).
Physicalexercise presents itself as a novel area to treat some of the symptoms ofSchizophrenia. In patients with Schizophrenia the Hippocampal volume is lowered(Fig 2). Whilst antipsychotic medications do not have an effect on hippocampalvolume, exercise is known to increase it (Pajonk 2010).Exercise also causes an increase in acetylcholine in the cerebral cortex,increasing neural transmission and activity. The cumulative effect of exercisehas shown to demonstrate significant physiological changes in patients withSchizophrenia.
Specifically, changes in hippocampal volume, cortical thicknessand increased serum brain-derived neurotropic factor. (Subramaniapillai, M 2016).Furthermore, individuals with Szchizoprenia havelowered levels of the presynaptic proteins SNAP-25 and complexin I and II, leadingto increased levels of cognitive impairment. Exercise may induce changes in theplasticity of synaptic proteins in the hippocampus thus improving cognitivefunction (Pajonk 2010). Additionally, arecent study found that in first episode patients promoting exercise as well ascognitive training could promote recovery.
Showing that exercise can be usedalong side cognitive training, to boost its effects in reducing symptoms whilstalso improving social interaction. (Ventura 2017). Exerciseand academic performance in school aged children Most teachers will tell youthat children are better behaved after they spend break time outside runningaround. What might be more surprising to learn is that, statistically, childrenwho engaged in regular aerobic exercise have higher levels of academicachievement that their sedate counterparts (Kim 2003).
Many countries have Removed PhysicalEducation from their curriculum in an effort to focus more on standardizedtesting and indeed, increase academic performance. However, recent studies haveshown that this actually has the inverse effect. Aerobic fitness has a positivecorrelation to academic achievement ( and bmi a negative one) (Castelli 2007).
When mathematics and readingscores were analyzed against aerobic fitness, the students with a higher levelof fitness outperformed the students with a lower level of fitness (Californian Department of Education 2001). Neuroanatomy involved inreading comprehension in children includes the prefrontal cortex (PFC) as wellas the posterior cingulate cortex (PCC) (Maguire1999). Additionally, one of theregions in the brain involved in mathematics is the bilateral regions of theintraparietal sulcus, in children specifically the dorsolateral prefrontalcortex is also activated. Bothmathematics and reading require activation of the frontopariteal network.Interestingly, fitness has also been linked to this network (Colcombe 2004). Therefore, it may follow that childrenwill potentially perform better academically with an increase in aerobicfitness.
It is important to note thatsome studies have found little or no correlation between children’s aerobic fitnesslevel and academic performance (Ahamed 2007).However, it is reasonable to assume that physical education is an important partof children’s wellbeing and that it does not dampen academic achievement,indeed in some cases it may enhance it. Conclusions Exercise presents itself as a novel treatment for avariety of disorders and diseases.
The relationship between aerobic fitness andneurodegenerative diseases is of crucial importance as the number of peopleliving to a later age is increasing. This means that, statistically, there isgoing to be more people developing these diseases. If prescribed exercise isincorporated into healthcare policy then there may be a delay in thedevelopment of these diseases. This may result in a reduced economic strain forhealthcare organisations. Additionally, encouraging patients who experience afirst episode with Schizophrenia to engage in regular physical activity hasbeen shown to quicken their recovery time.
The effect of exercise on theacademic achievement of children is also an interesting area as academicachievement (and inherently cognition) is not something traditionallyassociated with physical fitness. Whilst the use of exercise as a treatment for a varietyof diseases provides another treatment option for many patients it is importantto note that studies are not claiming that exercise should be the only form oftreatment issued. Additionally, there may be challenges in getting patients tocomply with exercise programs prescribed to them. This is an interesting anddeveloping area of research but at present, there has been little investigationinto the molecular mechanisms as to how exercise can have these effects andfurther research should be done to determine this.
To conclude, exercise, whenused in conjunction with other treatment plans, has the capacity to improve thesymptoms of many patients with neurological diseases.