Regular exercise changes the structure of body tissue in obvious ways, e.g. B. by reducing fat stores and increasing muscle mass. Less visible, but perhaps more important, is the profound impact that movement has on the structure of our brain – an impact that can protect and maintain the health and function of the brain throughout life. In fact, some experts believe that the human brain can depend on regular physical activity to function optimally throughout our lives.
Here are just a few ways that movement changes the structure of our brains.
Many studies suggest that exercise can protect our memory as we get older. 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 the shrinking of certain areas of the brain associated with memory. For example, an MRI (magnetic resonance imaging) study found that six months of exercise increased brain volume in older adults.
Another study showed that the shrinking of the hippocampus (an essential part of the brain for learning and memory) in older people can be reversed by walking regularly. This change was accompanied by improved memory function and an increase in the bloodstream’s neutropic factor (BDNF) derived from the protein brain.
BDNF is essential for healthy cognitive function because of its role in cell survival, plasticity (the brain’s ability to change and adapt based on experience), and function. Positive associations between exercise, BDNF, and memory have been extensively studied and demonstrated in young adults and the elderly.
BDNF is also one of several proteins related to adult neurogenesis, the brain’s ability to change its structure through the development of new neurons in adulthood. Neurogenesis occurs in very few regions of the brain – one of which is the hippocampus – and can therefore be a central mechanism involved in learning and memory. Regular physical activity can protect memory over the long term by inducing neurogenesis via BDNF.
While this relationship between exercise, BDNF, neurogenesis, and memory is very well described in animal models, experimental and ethical constraints mean that its implications for the functioning of the human brain are not entirely as clear. Nevertheless, exercise-induced neurogenesis is being actively researched as a possible therapy for neurological and psychiatric diseases such as Alzheimer’s, Parkinson’s and depression.
The brain is heavily dependent on blood flow and receives about 15% of the total body supply – although it only makes up 2-3% of the total mass of our body. This is because our nervous tissues need a constant supply of oxygen to function and survive. As neurons become more active, blood flow increases to the region where those neurons are located to meet demand. Hence, maintaining a healthy brain depends on maintaining a healthy network of blood vessels.
Regular exercise increases the growth of new blood vessels in the areas of the brain where neurogenesis occurs and creates an increased blood supply to aid the development of these new neurons. Exercise also improves the health and function of existing blood vessels and ensures that the brain tissue receives adequate blood supply at all times to meet its needs and keep it functioning.
Finally, regular exercise can prevent and even treat high blood pressure, which is a risk factor for developing dementia. Exercise works in a number of ways to improve the health and function of blood vessels in the brain.
Recently, a growing body of research has focused on microglia, which are the brain’s resident immune cells. Their main function is to constantly check the brain for possible threats from microbes or dying or damaged cells and to clean up any damage found.
With age, normal immune function decreases and low-level chronic inflammation occurs in body organs, including the brain, which increases the risk of neurodegenerative diseases such as Alzheimer’s. As we age, microglia become less effective at cleaning up damage and less able to prevent disease and inflammation. This means that neuroinflammation can progress and affect brain functions, including memory.
But recently we showed that movement can reprogram these microglia in the aged brain. It has been shown that exercise makes the microglia more energy efficient and is able to counteract neuroinflammatory changes that affect brain function. Exercise can also modulate neuroinflammation in degenerative diseases such as Alzheimer’s 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 the right kind of exercise – or getting enough of it – to keep the brain safe? As of now, we don’t have enough evidence to develop specific guidelines for brain health, although results so far suggest that aerobic exercise – like walking, running, or cycling – are the most beneficial. It is recommended that adults receive at least 150 minutes of moderate-intensity aerobic exercise per week combined with activities that maintain strength and flexibility to maintain good overall health.
It must also be noted that researchers do not always find in their studies that exercise has positive effects on the brain – probably because different studies use different exercise programs and measures of cognitive function, making it difficult to directly compare studies and results. Regardless, numerous studies show us that exercise is beneficial for many aspects of our health. Hence, it is important that you get enough. We need to be aware that we are taking our time to be active – our brains will thank us for it in the years to come.
High-intensity interval training (HIIT) can prevent cognitive decline provided by The Conversation
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