- Guillaume Lopez Lluc
- The conversation*
“Healthy men in a healthy body”. This quote is often used to claim the beneficial effect of physical activity on mental abilities. In fact, the sentence appeared in Satire X written by the Roman comedian Juvenal in the second century and was longer: it indicated that one should pray for a healthy mind in a healthy body (“orandum est ut sit mens sana in healthy body”).
But is it true that keeping a healthy, balanced and active body helps to maintain the mental capacities of our brain? Yes, and there is plenty of scientific evidence to prove it, especially when it comes to aging.
The brain loses volume during aging.
As we age, tissues and organs degenerate. The ability to maintain cell functionality decreases and this is accompanied by loss of tissue. It also occurs in the brain, with the resulting neurodegeneration or loss of neurons.
Whether in pathologies such as Alzheimer’s disease or in loss of functionality due to aging, different changes associated with loss of function occur in the brain. Among them, thinning of the cortical area, loss of gray (neural bodies) and white (nerve conduction) tissue, increased volume of the ventricles (holes inside the brain where the cerebrospinal fluid is located) and decrease in neurons in different areas, especially in the hippocampus.
In a longitudinal study involving hundreds of volunteers for years, the Baltimore study, it was shown that the reduction in metabolic capacity associated with aging is linked to the increase in the volume of the cerebral ventricle – the “hollow” space ” of the brain – . And that leads to a increased neurodegeneration and atrophy of the thinking organ.
If the reduction in metabolic capacity implies a loss of brain volume, it can be inferred that better use of energy by exercise could slow the loss of tissue in the brain.
More exercise, more memory
It’s like that? Answering it is not easy. Above all, because one of the main obstacles we encounter in determining the effect of any intervention on the brain is the practical impossibility of quickly verifying its consequences.
The brain is not like blood or muscle, which quickly show an easily measurable response directly or from blood components. The good news is that the advent of increasingly reliable imaging methods can detect certain structural changes in certain areas of the brain.
We have long had proof that the practice of physical exercise improves cognitive abilities and increases the size of certain areas of the brain, in particular those related to memory.
For example, in 2011, an article was published in PNAS (Paper of the US National Academy of Sciences) indicating that physical exercise increases the volume of the hippocampus, the part of the brain where memory resides. Other studies in older people have shown that physical exercise also prevents loss of volume in this area of the brain.
On the other hand, the practice of controlled physical exercises in a population of elderly people has shown that there is a positive correlation between the practice of physical exercises and the amount of gray matter in other sensitive areas of the brain. to degeneration. associated with aging.
We tend to think of our body as a compartmentalized system. If we have a liver problem, we focus on the liver, and if it’s on the kidney, then on the kidney. But our body does not work like that: everything is interconnected. This is why a kidney problem can end up making heart disease worse, or a liver problem can cause cerebral ischemia. As we age in particular, the complex balances of the body are in a very precarious situation.
When we exercise, we subject our bodies to moderate stress because we force the cells to increase their energy expenditure. This involves mobilizing nutrients, which must move from stores to muscles. All of the physiological changes needed to cope with this moderate stress are known as hormesis.
In the process of hormesis, the muscles release substances that inform the rest of the organs that energy demand is increasing. These substances are called myokines and are released into the blood, which distributes them to the rest of the organs.
Some of these myokines reach the brain and induce the expression of genes and proteins there that increase the ability of neurons to establish new connections or strengthen existing ones.
One of these myokines is called BDNF (brain-derived neurotrophic factor), which is essential for neurons to make connections and thus keep them active. In this simple way, we can explain why physical exercise maintains brain volume during aging.
On the other hand, physical exercise also increases blood flow and oxygenation, which has a positive impact on brain activity also in the elderly. In addition, other studies have shown that moderate physical exercise produces anti-inflammatory effects which can generate effects in the brain, for example, reducing the progression of Alzheimer’s disease or senile dementia.
Scientific evidence, both direct and indirect, clearly shows that engaging in physical activity as you age helps prevent brain degeneration, giving full meaning to the phrase “mens sana in corpore sano”.
It is better for us to avoid inactivity and a sedentary lifestyle if we want to add life to years and not just years to life.
*Guillermo López Lluch is a professor and researcher at the Andalusian Center for Developmental Biology and a researcher in metabolism, aging and immune and antioxidant systems at the Pablo de Olavide University in Seville. His article was published in The Conversation of which you can read the original version here.
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