Moderate physical activity improves cognitive function and enhances the restructuring of neuronal synapses, necessary for learning and memory. It also induces changes in brain volumes and connectivity. However, the evidence suggests that long-term strenuous exercise is not associated with these benefits. “We recently demonstrated that high-intensity physical activity promotes vascular lesions. More specifically, it damages the aortic and carotid arteries, dilating them and increasing their rigidity,” says Eduard Guasch, a cardiologist at the Hospital Clínic de Barcelona and head of the IDIBAPS Arrhythmias and physical activity group. “But how does strenuous exercise influence brain health?” he wonders.
To answer this question, Guasch and his team studied the effects of different types of physical activity in an animal model. Over a period of 16 weeks – roughly equivalent to 10 human years – a first group of rats followed a regimen of moderate exercise reproducing an active lifestyle, using a treadmill adapted for rodents. A second group was subjected to a very high-intensity routine, similar to that of people who run marathons or practice extreme sports. Finally, a third group – the sedentary group – remained in their cages.
“The data, published in the journal Annals of the New York Academy of Sciences, shows that moderate physical activity enhances learning ability and motivation compared to a sedentary lifestyle. However, this effect was not observed in the strenuous exercise group, whose results are similar to those of the sedentary group”, says Guasch. “Using magnetic resonance imaging, we also saw that moderate training induces changes in the structure and function of the brain. Specifically, this regimen strengthens the connections between the different regions. Moderate exercise also increases cerebral blood flow. These effects did not appear after high-intensity exercise. All this could explain the cognitive differences observed between the different groups of animals”.
The research team also found that strenuous exercise alters mitochondrial function. “Mitochondria generate the energy necessary for the correct functioning of all cellular processes. They are often compared to a power plant, and their dysfunction is linked to oxidative stress and neuronal degeneration. Our data suggests that high-intensity physical activity could induce transient oxidative stress, which is harmful to the brain tissue. However, this hypothesis still needs to be verified. What we can conclude from our study is that moderate exercise is the training type that best optimises the cognitive benefits associated with physical activity”, concludes Guasch.
Researchers from the University of Barcelona’s Institute of Neurosciences, the Biomedical Research Networking Center on Cardiovascular Diseases (CIBERCV) and the National Council on Science and Technology (CONACYT) of Mexico also contributed to the study.
Reference article
Sangüesa G, Batlle M, Muñoz-Moreno E, Soria G, Alcarraz A, Rubies C, Sitjà-Roqueta L, Solana E, Martínez-Heras E, Meza-Ramos A, Amaro S, Llufriu S, Mont L, Guasch E. Intense long-term training impairs brain health compared with moderate exercise: Experimental evidence and mechanisms. Ann N Y Acad Sci. 2022 Oct 18. doi: 10.1111/nyas.14912.