Stretching the grey matter
Exercise and brain health

The benefits of exercise go way beyond the physical and the aesthetic. Heidi Mitchell discusses the correlation between cardiovascular health and brain health, and highlights the fitness professional’s role in helping to prevent dementia.

In the world of fitness training, it is easy to get caught up in the day-to-day fundamentals of planning sessions and being a motivator. We inadvertently narrow our perspective on the impact we are having on the future lives of our clients and often think merely in terms of the short-term improvement of a certain aspect of their fitness, such as endurance or strength. We like to project ourselves as mentors, but rarely do we focus our sights on working towards preventing the myriad devastating health issues that afflict modern society, such as heart disease and cancer, and the indisputable fact that what we do with our clients now will profoundly influence what happens to them in later life.

Prevention better than cure

In the 1400s a researcher and teacher by the name of Desiderius Erasmus coined the well-known proverb: ‘prevention is better than cure’, which purports that it is far more prudent to avoid disaster than to deal with it after it occurs. In terms of our health, an enormous amount of significance lies in this saying, with research suggesting that we are able to make a substantial difference to our own and our clients' health beyond short and long-term exercise goals.

When we think of physical exercise in later life, we predominantly concentrate on the idea of strengthening the body so we are more capable in our general activities, as well as preventing the risk of falls and therefore hip replacements. However, physical exercise is also an essential ingredient in the prevention of disease and early brain decline, and it is this topic that we should all spend more time understanding and promoting. This point of view on disease prevention is corroborated by over a decade’s worth of scientific research on dementia by Dr Michael Valenzuela; specifically thatthere is an undeniable correlation between cardiovascular health and brain health.

Practical applications for brain health

In Australia, it is estimated that some 267,000 people are affected by dementia, making it an urgent social and medical issue. Over the next 20 years, it is anticipated that degenerative brain diseases (predominantly Alzheimer's disease and vascular dementia) will overtake heart disease as the number one cause of death in Australia. Given that dementia is a progressive illness (i.e. once it has commenced it continues to get worse), these alarming statistics should make fitness professionals sit up and take notice because, ultimately, isn't our goal to improve the overall health and wellbeing of clients, and therefore, their future health? Isn't the idea of playing an active role in the prevention of something as debilitating as dementia through physical exercise an exciting one? Surely the answer to these questions is a resounding ‘yes!’

The cardio/brain link

To understand the link between cardiovascular health and brain health, a brief look at the complexities and sheer enormity of nerve system communication is useful, as proper functioning of this system is a key feature of a healthy brain. The human brain comprises approximately 100 billion cells in constant interaction with each other, largely via the spaces between them called synapses. The average pre-synaptic neuron synapses with approximately 1,000 other neurons, but the average post-synaptic neuron has up to 10,000 synapses, and some post-synaptic neurons in the cerebellum can have up to 100,000 synapses. These inconceivable numbers give us an indication of the astounding range of variables within the nervous system, as well as the vast opportunity for interference with ideal functioning.

In order for a nerve signal – or action potential – to be propagated along the length of the nerve cell, a vast number of intricate processes occur, commencing with a certain charge threshold requirement in the cell body of the neuron and then a ‘domino’ effect of gated channels opening with various ions moving in and out of the cell and finishing with what are called ‘neurotransmitters’ being released into the synaptic clefts to allow the message to continue on to the next nerve cell. If this isn’t complicated enough, a ‘sodium potassium pump’ is continually forcing ions out of the nerve cell so as to enable it to conduct another nerve signal. Interestingly for fitness professionals, this active process is powered by adenosine triphosphate (ATP). Unsurprisingly, this multifaceted system of communication requires large amounts of energy, and in terms of the human body, the brain uses notably more energy at rest than any other part.

As fitness professionals we are aware of the energy requirements of the body in terms of musculature, aerobic and anaerobic activities. We understand the necessities of ATP, and specifically the requirements of glucose and oxygen during workouts, but what importance do we place upon their involvement with brain function in terms of sustaining the core cognitive functions that are applicable to dementia: memory, attention, inhibition, personality? Probably none, yet their significance is indisputable. According to Dr Valenzuela, in his book Maintain Your Brain, ‘we burn glucose for all sorts of reasons, but the most important is to keep a high, steady and reliable voltage across the membrane of each of the brain's 100 billion cells so that, when required, each cell can communicate with other cells in a deeply mysterious process that allows regulation of our basic body functions. It should be apparent, therefore, how crucial a good clean supply of energy is for proper brain function.‘ Additionally, like muscles, brain cells require a steady supply of glucose and oxygen to eradicate carbon dioxide and other waste products. It is apparent, therefore, that the simple act of partaking in physical exercise will lead to quantifiable changes to brain structure and function, and any serious interruption to the proper blood flow to the brain will be highly destructive. And what is the key to ensuring good blood supply through the carotid arteries? Good cardiovascular health.

New growth

It would seem from this that the link between physical exercise and improved cognition is simply a result of greater blood flow, metabolic fitness and decreased vascular disease. However, research has indicated that physical exercise has far greater power in the prevention of dementia than these factors. In Maintain Your Brain, Valenzuela states that although brain function ‘will benefit from physical exercise because of its powerful disease-busting effects on conditions such as diabetes, hypertension and obesity’, it also, fascinatingly, will have some bearing on new growth in the brain: new brain cells, new connections between brain cells and new blood vessels. This is a stimulating concept for fitness professionals, because it takes the product of personal training far beyond the realms of physical fitness.

Of course, given the intricate workings of the human body, despite the critical role they play, cardiovascular health and healthy blood pressure are not the only components of dementia prevention. According to Valenzuela, there are a number of other significant factors that should be undertaken in conjunction with physical exercise to maximise the chances of preventing dementia in later life.

However, for fitness professionals, the link that exists between exercise and the prevention of dementia is irrefutably pertinent and hopefully inspiring. We have a responsibility that comes with our physical knowledge base beyond giving our clients a fun and engaging exercise session and ensuring biomechanically sound and technically safe execution of exercises, and that is to educate. With physical activity playing such a major role in preventing the onset of dementia, we should be making it a priority to educate clients and members of the public about the far-reaching benefits of exercise. By so doing, we can facilitate a far better old age for our clients, and contribute to the wellbeing of the community at large. When you think about it, it’s a no-brainer.

 

Heidi Mitchell
Heidi is a part time assistant with the Regenerative Neuroscience Group at the University of New South Wales. She also co-founded the Sydney‑based specialised training company, Breathe Fire, where she works alongside Craig Douglass delivering courses and highly technical training sessions. To contact Heidi visit www.breathefire.com.au