Centre for Neuroscience and Cell Biology (CNC) and the European Project FOIE GRAS, coordinated by CNC, have been working closely with the organizing team of the European University Games 2018 in order to promote exercise practice and healthy living.

 

As part of this EUG2018-CNC partnership, the CNC researchers and the FOIE GRAS ESRs have written a series of chronicles that build upon the benefits of exercise practice on health. 


These chronicles result from the collaboration between the Center for Neuroscience and Cell Biology (CNC) of the University of Coimbra, the European Advanced Training Network FOIE GRAS (http://www.projectfoiegras.eu), the Erasmus+ Program and the Academic Sports Federation University (FADU) in the scope of the European University Games Coimbra 2018.

 

These illustrated chronicles will be published in Portuguese at the local newspaper Diário de Coimbra and you can read here the English version on our website. 

 

The FOIE GRAS coordinator, Paulo Oliveira wrote the preface chronicle as an introduction to the series. Know more about the project here or here.

 

 The Inner Beauty of Being Active

 


Chronicles


chronicles

Memory Run - About the cognitive benefits of exercise

Human evolution took place throughout a period of long centuries in which humans were hunter-gatherers and continuously performed intense physical activity. The human genes of people today were naturally selected throughout the centuries to favor this pattern of vigorous physical activity. It is therefore not surprising, that the abrupt lifestyle changes that we underwent during this past century, resulting from an increased sedentarism that characterizes the activity habits of most of us, are at the origin of a wide range of chronic disorders affecting modern society. In fact, it is known today, that exercise practice has profound beneficial effects for physical and mental well-being.

Exercise practice is probably one of the most effective ways of improving our cognitive capacity without having to resort to pharmaceutical drugs. Individuals with a good physical condition, especially regarding the cardiovascular system, generally obtain better results in cognitive tests, and a lifelong practice of sports is associated to a better memory capacity. Physical exercise provides these benefits to all the different extracts of the population, from children to adults of all ages, including old people. Exercise is also beneficial in several neurological and neurodegenerative diseases,  inducing an enhancement of cognitive capacities and improving the good disposition of the patients.

In the last few years, several studies both in animals and humans have been carried out with the objective of understanding the mechanisms that underlie the beneficial effects of exercise practice on the brain. There is evidence that physical activity results in structural transformations on the brain, in changes on the communication patterns between neurons and in vascular alterations.

 

Running against time

The hippocampus is a region of the brain that is essential for the formation of new memories and its volume diminishes both with aging and in response to cognitive disorders such as neurodegenerative diseases. A reduction in the volume of the hippocampus in these situations is attenuated by practicing exercise. Body fitness is associated with a greater hippocampal volume and a sharper memory. Aerobic physical exercise (of long duration and low intensity) 3 times a week for a period of at least 3 months can prevent or even reverse the reduction of the volume of the hippocampus associated with age. Other brain regions, such as the entorhinal cortex and the pre-frontal cortex also benefit with an increase in volume in response to exercise practice.

 

New neurons in the adult human brain

Contrary to what was thought up until now, recent studies demonstrated that the formation of new neurons, or neurogenesis, is a phenomenon that takes place in the adult human brain, particularly in a sub-region of the hippocampus called the dentate gyrus. It is thought that these new neurons are integrated in the existent circuits and play a role in the formation of memories. Exercise, running in particular, results in a 2 to 3 fold increase in the neurogenesis of the hippocampus, a phenomenon that is in agreement with the beneficial effects that running has on memory. On the other hand, running is also associated with changes on the morphology of the new neurons formed in the adult dentate gyrus, and in the way these establish connections with one another. In these neurons, physical exercise accelerates the formation of spines, the neuron structures where communication takes place, and it increases the complexity of neuronal networks in this area. It is also well established that physical activity increases synaptic plasticity on the hippocampus, the process that allows neurons to fine-tune the efficacy of their communication with one another, and which is thought to be the cellular base for the processes of learning and memory.

 

How is it that exercise affects the brain?

Exercise practice has beneficial effects on the brain at several levels. An increase in the cerebral vasculature caused by sports practice allows for a better oxygenation of the brain and a better efficiency on the transport of nutrients and molecules with beneficial effects for the cells. This way, it is possible to provide all the brain cells with the necessary components to ensure its high activity. Studies performed in humans confirmed that, as a response to exercise, there is an increase in the blood flow going through the brain, and revealed that physical activity prevents the blood flow reduction observed in older individuals.

Other studies performed both in humans and laboratory animals demonstrated that running increases the levels of BDNF in the hippocampus, a protein with several functions in the nervous system, including the maintenance and survival of neurons and its protection in disease conditions (for instance on cerebrovascular accidents). This increase in BDNF was associated to the formation of new neurons in the hippocampus and to a strengthening in the communication between nervous cells in this brain region, as well as an improved capacity for memory formation.

On the other hand, during exercise, peripheral organs such as the skeletal muscle, the adipose tissue and the liver release molecules to the bloodstream that have effects on the brain. These molecules are starting to be studied just now. For example, in 2016 researchers identified Catepsin B, a protein produced by muscle cells that has effects on the synaptic plasticity induced by exercise practice. This protein promotes the expression of BDNF and the differentiation of new neurons on the hippocampus. Mice that are incapable of producing Catepsin B do not present the beneficial effects that practicing exercise has on cognitive capacity, which suggests that the production of this protein in the muscle, induced as a response to exercise performance, is necessary for the effects that exercise has on memory.

 

The pleasure associated to physical exercise

It is common to find people that clearly find great pleasure in the practice of exercise. We are now starting to understand why. The practice of physical activity stimulates groups of neurons that use the neurotransmitter dopamine and that are generally associated to the positive reinforcement of behaviors. The activation of these neuronal circuitry is responsible for the frequent return of rodents to the cage running wheel that allows them to practice exercise. This effect in rodents can mirror that of voluntary physical activity in humans and the associated pleasure, which leads to continued exercise practice.

It is safe to say, that in adopting a regular practice of exercise we are making our body more compatible with our genetic inheritance, improving our physical, mental and cognitive health and minimizing the risk of some diseases afflicting modern society.

 

Author: Ana Luísa Carvalho and Carlos Duarte are Principal Investigators at the Center for Neuroscience and Cell Biology (CNC), University of Coimbra (UC) and Professors at Department of Life Sciences of the University of Coimbra (UC).

 

The project: This chronicle results from the collaboration between the Center for Neuroscience and Cell Biology (CNC) of the University of Coimbra, the European Advanced Training Network FOIE GRAS (http://www.projectfoiegras.eu), the Erasmus+ Program and the Academic Sports Federation University (FADU) in the scope of the European University Games Coimbra 2018.

 

Coordination: Anabela Marisa Azul, João Ramalho-Santos, Mireia Alemany i Pagès, Paulo Oliveira and Sara Varela Amaral

 

Illustration: Rui Tavares

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