There is plenty of information in the public domain on the benefits of a regular exercise programme to enhance our physical wellbeing and reduce the likelihood of obesity and prevent diseases such as cancer and diabetes. The internet is awash with websites promising fast fat-loss exercise programmes, muscle growth and prolonged healthier lives. The focus is often-times on our physical bodies, in essence the muscular skeletal system, i.e how we look. However, very little information or attention is dedicated to one very important part of our anatomy that is crucial to a long, healthy and fulfilled life without which a well-sculpted, fit body is useless - and that is our brain! This blog will demonstrate the importance of exercise in developing and keeping the brain mentally fit and free of disease, particularly important given the fact that we are an ageing population and therefore more likely to witness an increase in the prevalence of crippling diseases such as Alzeihmer's disease.
An Ageing Population
In 1900, average life expectancy was approximately 47 years, compared to today's which is roughly 78. Men and women who make it to 65 can expect to live in to their 80's. With this increased longevity it makes sense to maintain a healthy body to live a full, productive life. Through more research we have begun to learn the importance of the biological relationship between the body and the brain. Scientists are shouting loudly that what is good for our bodies is also good for our brains. Just as we lose it, if we don't use it (i.e. exercise) our bodies, the same is true of our brains. It is easy to conceive of our muscular systems changing and adapting to exercise as we can see before our eyes the adaptations. The brain is no different. Neuroscientists have shown that the brain remains 'plastic' or changeable in later life whereas previously it was written off after a certain age. Neurons can make new connections and networks in response to learning. The result is that just like muscle tissue, brain tissue is able to change in response to exercise no matter what age you are - good news!
Brain Power and Brain Disease
The complex anatomy of the human brain and its thirst for energy means that it consumes around 20 per cent of the body's oxygen supply and 20 per cent of its glucose. The intricate web of neurons that control our every move and thought have the ability to grow and develop new pathways in response to learning something new. That's the good news. The bad news is that as early as the age of 40 we start to lose approximately 5 per cent of brain volume every decade of life. We also encounter -after the age of 65- brain disorders such as Alzheimer's disease. Alzheimer's Disease International, based in the UK estimates that there are 35.6million people living with dementia worldwide. However, whereas it is commonly assumed that this cruel disease is a normal response to ageing, the science is demonstrating that although age is one of the most important risk factors, genetics and lifestyle factors also play a major role; approximately one-third of brain ageing is down to genetics and the other two-thirds is down to lifestyle.
Brain Exercises, Aerobic Exercise and Metabolic Disease
The assumption with brain disorders is that they start as we enter old age. However, like our bodies our brains age from the get go and therefore how we treat our brains from an early age and throughout life is the same as how we treat our bodies. By keeping the brain and body active may be the most important ways to reduce the risk and possibly prevent brain disease. Indeed, studies suggest that exercise can lower the risk of dementia by 50-60 per cent, and decrease Alzheimer's risk by 60 per cent. But what exercise is best for reducing Alzheimer's risk? The research (by Weuve et al, 2004) suggests that it is aerobic exercise as this strengthens the connections between brain cells, creating more synapses, developing neurons and increasing dendritic branches. Indeed, positive results in memory and intelligence tests were indicated even with modest forms of aerobic exercise such as 90 minutes walking a week with best results coming from four hours running or 12 hours walking a week. Lack of exercise, or more pertinent in this case aerobic exercise, means that the brain receives less of the blood oxygen and glucose that is so vital to its functioning. Lack of physical activity is also a risk factor as we know for heart disease, diabetes, cancer, stroke, obesity and high blood pressure, which in turn can have an effect on brain function. This inextricable link between physical disease and our cardiovascular and metabolic systems means exercise is vital to preventing problems later in life. For example as our insulin levels drop throughout the ageing process, glucose has a harder time getting into the body's cells to fuel them, causing blood glucose levels to increase. This raises the risk of diabetes which in turn increase the risk of dementia by 65 per cent and creates waste products that damage blood vessels and increases the risk of stroke and Alzheimer's disease. Together with high cholesterol which increases the risk of dementia by 43 per cent and obesity which doubles the likelihood of dementia then the risks may be far higher.
Age and high levels of stress does eventually cause neurons like other cells in the body to decrease connections and it is when these connections outpace the new construction of connections that we witness problems with mental function. Stress also brings with it high production of the hormone cortisol which has been linked to cell death in the hippocampus - the part of the brain that is associated with long- and short-term memory and spatial orientation. Learning to cope with stress and an instigating a well-planned exercise training plan can help arrest some of these changes.
Type of Exercise to Improve Brain Function
A lot of research supports the theory that aerobic training has a positive impact on the ageing brain. A 2005 study by Kramer et al looked at healthy adults between the ages of 60 and 75 and found that mental tasks involved in executive control - monitoring, scheduling, planning, inhibition, and memory - improved in a group doing aerobic exercise, but not in a control group. Other long term studies show similar results. So why is this case? Firstly, aerobic exercise increases brain-derived neurotrophic factor (BDNF), a protein that has a fertilising effect on the brain's neurons and dendrites, helping them grow and flourish. This protein also plays a role in neurogenesis, the process of cell division and new growth (of neurons).
Secondly, regular aerobic exercise also increases insulin-like growth factor (IGF-I) and vascular-endothelial growth factor (VEGF), two proteins that serve to build and maintain activity within the cell circuitry ( the infrastructure of neuronal connections). The familiar rush or buzz experienced by runners and other types of aerobic training has been attributed to hormone activity in the brain - these neurotransmitters such as Serotonin and Norepinephrine help transmit signals across synapses. The latter amplifies signals that influence attention, perception, motivation and arousal. All are boosted by aerobic training. More importantly perhaps aerobic exercise sends lots of oxygen-rich blood to the brain delivering glucose and oxygen, whilst removing waste products that inhbit the process. As regular resistance training increase muscle density and size, brain volume also grows with regular aerobic exercise due to an increase in capillaries, blood volume and nerve cell growth. And finally, just how we now understand that high-levels of glucose in the blood can lead to diabetes, high levels also effect brain health by decreasing levels of BDNF, so it is important that glucose is kept at an optimum level, achieved with regular aerobic training.
Whilst we are more susceptible to diseases as we age due to the inevitable decline in cellular regeneration the good news is that it is never too late to start an exercise programme that will not only help you perform daily tasks more efficiently but will also give the old grey matter a boost. If anything, it provides another motivation to begin an exercise programme as science is proving you will be getting maximum return for your investment proving that wherever the body goes the mind is sure to follow.