During the days of reflection, Mariano Rajoy used to dedicate his mornings to playing sports. On the eve of the December 2015 elections, those elections that shook the political board and confirmed the end of bipartisanship, the PP candidate spent the morning with his dog Rico, walking at a fast pace through the gardens of La Moncloa. Like a kind of I want and I can’t, without running but almost. Rajoy’s fast march, which caused so much fun on social networks at the time and was later rescued for a spot campaign in 2016, however, it has become one of the best sports to combat cardiovascular risk. Researchers at the Hospital del Mar in Barcelona have shown that moderate and vigorous physical exercise, such as that practiced by the former president, modifies DNA structures. Specifically, it acts on the function of a gene that is linked to the regulation of triglycerides. In large quantities, these fatty acids are bosom friends of cardiovascular ailments.
Well known are the benefits of physical exercise for health. It reduces the risk of cardiovascular diseases, prevents cancer and plays a crucial role in the fight against diabetes or obesity, the great epidemics of the 21st century. The scientific community has long taken this for granted, but continues to search for the mechanisms that explain these benefits. For this reason, a group of researchers from the Hospital del Mar Medical Research Institute (IMIM) has focused on studying how genes respond to the practice of physical exercise. “We already knew that sport reduces the risk of disease. We know that it impacts how information from our genes is expressed. What we are trying to contribute are the mechanisms that explain why”, summarizes Dr. Roberto Elosua, from the IMIM Cardiovascular Epidemiology and Genetics Group.
Elosua’s team focused on a specific epigenetic process, DNA methylation. The epigenome is the entire network of chemical compounds and proteins that stick to genes and, although they do not alter their sequence, they do cause chemical variations that affect their functions. Methylation is one of those epigenetic factors that occurs when some of these compounds act as a kind of switch, turning gene activity on or off.
Thus, the researchers took the physical activity data of 2,544 people from two population cohorts -the Catalan RECIGOR and the American Framinghan- and, from the blood samples of the volunteers, analyzed more than 400,000 methylation marks distributed in the DNA of each of the individuals. “We found that light physical activity [como dar un paseo] was not associated with any methylation change. The only one that was related to changes was moderate-vigorous activity”, summarizes Alba Fernández Sanlés, one of the signatories of the study, which has been published in the scientific journal Medicine and Sicence in Sports and Exercise.
Specifically, among the 400,000 methylation marks analyzed, the scientists found two areas where physical exercise modified the performance of DNA. “One of them was in the DGAT1 gene, which regulates the metabolism of triglycerides. People who do more physical activity have less methylation. And having this low-methylated gene is good because it makes the metabolism of triglycerides more activated”, concludes Elosua. In high concentrations, this type of fatty acid increases the risk of developing cardiovascular ailments.
The other region of DNA where the researchers found changes in methylation in relation to the level of physical activity was in an intergenic region – what is known as junk or dark DNA, which accounts for 98% of the genome and of which many are unknown. functions—an area that other studies have linked to factors linked to aging. According to the IMIM researchers, this finding could explain why the regular practice of physical exercise is associated with greater longevity.
“There are previous experimental studies in which groups of people have been trained to see if there are changes before and after, but they were small samples and of young people. Ours is an observational study of the general population, we did not intervene in the practice of physical activity. We only analyze the methylation marks distributed throughout the DNA, if they are highly or slightly methylated, and we see if physical activity is related to this activity and what type of exercise is better”, says Elosua. Researchers argue that moderate activity (dancing or brisk walking) or vigorous activity (jogging or playing sports for at least 30 minutes) is best for cardiovascular health. “You don’t have to be a Kilian Jornet to get beneficial health effects. By practicing fast walking, like Rajoy, you already get benefits”, adds the doctor.
“This study explains, in part, how our body chemically adapts to exercise and that this can lead to benefits for better fat metabolism and, eventually, a lower risk of cardiovascular disease,” says the director of the Epigenetics and Biology program of Cancer of the Bellvitge Biomedical Research Institute, Manel Esteller, who has also participated in the study. Previous studies, such as one from the Karolinska Institute in 2014, also established that long-term resistance training stably alters the epigenetic pattern in human skeletal muscle. In another from Lund University (Sweden), researchers found that physical exercise changes the epigenetic pattern of genes that affect fat storage in the body.
“It is the study that most people use to see the relationship between physical exercise and DNA methylation. This research confirms how lifestyle allows modulating whether or not some areas are expressed. And that is through epigenetics”, explains Iñaki Martín, head of the biomedical epigenetics research group at IDIBAPS in Barcelona. This researcher, unrelated to the study, maintains that the finding of changes in an intergenic zone “can be very important”. “What remains to be known is which is the target gene related to this epigenetic change. And, at a functional level, what these changes do”, he adds.