Regular exercise changes the structure of our body’s tissues in distinct ways, such as decreasing fat stores and increasing muscle mass. Less visible, but perhaps more importantly, is the profound impact that exercise has on structure of our brain – an influence that can protect and preserve brain health and function through life. Some experts even believe that the human brain can depending on regular physical activity to function optimally throughout our life.
Here are just a few of the ways that exercise changes the structure of our brain.
Many studies suggest that exercise can help protect our memory as we age. This is because exercise has been shown to prevent the loss of total brain volume (which can lead to decreased cognitive function), as well as prevent shrinkage in specific brain areas related to memory. For example, a magnetic resonance imaging (MRI) study showed that six months of exercise training in older adults increases brain volume.
Another study showed that shrinkage of the hippocampus (a brain area essential for learning and memory) can occur in older people. vice versa by walking regularly. This change was accompanied by improved memory function and an increase in protein brain-derived neutrope factor (BDNF) in the bloodstream.
BDNF is essential for healthy cognitive function due to its role in cell survival, plasticity (the brain’s ability to change and adapt through experience) and position. Positive links between training, BDNF and memory have been extensively researched and demonstrated in Adolescents and elderly.
BDNF is also one of several proteins linked to neurogenesis in adults, the brain’s ability to modify its structure developing new neurons during adulthood. Neurogenesis only occurs in very few brain regions – one of which is the hippocampus – and so may be a central mechanism involved in learning and memory. Regular physical activity can protect the memory in the long run by induce neurogenesis via BDNF.
While this link between exercise, BDNF, neurogenesis and memory is very well described in animal models, experimental and ethical limitations mean that its importance to human brain function is not so clear. Nevertheless, exercise-induced neurogenesis is being actively explored as a potential therapy for neurological and psychiatric disorderssuch as Alzheimer’s disease, Parkinson’s disease and depression.
The brain is highly dependent on blood flow and receives about 15% of the body’s total supply – despite making up only 2-3% of our body’s total mass. This is because our nerve tissues require a constant supply of oxygen to function and survive. When neurons become more active, blood flow flows into the area where these neurons are located increases to meet demand. As such, maintaining a healthy brain depends on maintaining a healthy network of blood vessels.
Regular exercise increases the growth of new blood vessels in the regions of the brain where neurogenesis occurs, increasing the blood supply that supports its development new neurons. Exercise also improves health and function of existing blood vessels, so that brain tissue consistently receives adequate blood supply to meet its needs and maintain its function.
Finally, regular exercise can prevent and even treat it hypertension (high blood pressure), which is a risk factor for this development of dementia. Exercise works in several ways to improve the health and function of blood vessels in the brain.
Recently, a growing body of research has focused on microglia, the brain’s resident immune cells. Their main function is to be constant check the brain for potential threats from microbes or dying or damaged cells, and to clean up any damage they find.
With age, normal immune function declines and chronic, mild inflammation occurs in body organs, including the brain, where the risk of developing neurodegenerative disease, such as Alzheimer’s disease. As we age, microglia become less efficient at clearing up damage and are less able to prevent disease and inflammation. This means neuroinflammation may increase, which affect brain functions – including memory.
But recently we have shown that exercise can reprogram these microglia in the old brain. Exercise was shown to make the microglia more energy efficient and able to counteract neuro-inflammatory changes that affect brain function. Exercise can also modulate neuroinflammation in degenerative conditions such as Alzheimer’s disease and multiple sclerosis. This shows us that the effects of physical activity on immune function can be an important target for therapy and disease prevention.
So how can we make sure we’re doing – or getting enough – the right kind of exercise to protect the brain? So far, we don’t have enough evidence to develop specific brain health guidelines, although the findings so far suggest that the greatest benefits can be derived from aerobic exercise – such as walking, running or cycling. It is recommended that adults take a minimum of 150 minutes a week moderate-intensity aerobic exercise, combined with activities that maintain strength and flexibility, to maintain good general health.
It should also be noted that researchers do not always find exercise has a beneficial effect on the brain in their studies – probably because different studies use different exercise training programs and measures of cognitive function, making it difficult to compare studies and results directly. Regardless, a lot of research shows that exercise is beneficial for many aspects of our health, so it’s important to make sure you’re getting enough. We need to be aware that we are making time in our time to be active – our brains will thank us for it for years to come.