[ad_1]
“After the study, we found that healthy young people of similar composition have different resistance to cold. At the same room temperature, the internal body temperature of some people falls faster than others, even though the rates of heat production were similar. However, we were unable to explain this phenomenon in any way. Then we start looking for possible potential causes. We hypothesize that the absence of the α-actinin-3 gene, which is associated with energy production (metabolism), results in resistance to frost. This gene is found in the muscles and has a direct effect on the production of heat in cold conditions, ”says Marius Brazaitis, a professor at the Lithuanian University of Sports who led the research team.
It is estimated that around 1.5 billion of the world’s population does not have this gene. Scientists explain this by the fact that 50-70 thousand years ago, in search of new hunting grounds, the tribes of the African continent moved to harsher lands – central and northern Europe, the Caucasus region. Their bodies have adapted to survive harsh conditions by losing this gene.
To date, the gene for α-actinin-3 has been more associated with the specificity of muscle contraction: people with this gene have greater physical strength and speed, and those without it have greater physical endurance.
“The results of our study increase our understanding of the evolutionary aspects of human migration. While energy efficient heat production for people lacking α-actinin-3 would have been an advantage in moving to a colder climate, it could actually be a disadvantage in modern society. In the modern world, man protects himself from the effects of cold in heated homes by dressing in appropriate clothing, consuming more food than necessary. For this reason, genetically determined more efficient energy consumption is likely to reduce calorie loss, which in the long term can lead to obesity and metabolic disorders, ”says prof. M. Brazaitis.
According to the professor, the most important factor in determining our resistance to cold is the environment in which we live, the clothes we prepare and the food we eat, and the cold gene is like a “rudiment” that, with the right stimulation, can achieve unexpected results.
“The loss of the α-actinin-3 gene during evolution has increased resistance to cold through more efficient heat production in the muscles. Interestingly, people lacking the α-actinin-3 gene shivered less in the cold and cooled down more slowly. They felt more comfortable when they were cold and most of the heat was generated without shivering, that is, increasing muscle tone. What is new is also that until now it was thought that thermoregulation of tremor occurred by activating brown adipose tissue. Our study revealed that for those who do not have this gene, brown adipose tissue is not even activated and the production of heat exclusively involves the processes that take place in the muscle ”, says prof. M. Brazaitis.
The study of the gene for α-actinin-3 and its effect on cold lasted 10 years. In the first stage of the research, 4 main researchers from the Lithuanian Sports University participated: prof. M. Brazaitis, researchers dr. Nerijus Eimantas and dr. Henrikas Paulauskas, chief researcher prof. Dr. Tomas Venckūnas. They were later joined by researchers from the Karolinska Institute in Sweden, who performed analyzes of muscle protein expression. In the third phase, Australian researchers were invited to breed mice with a “knocked out” (artificially deleted) α-actinin-3 gene.
This study changes the general understanding of all scientists in the field that, depending on the gene, cold affects different mechanisms involved in metabolism and heat production. There may be interesting research in the future on how α-actinin-3 deficiency is associated with obesity and metabolic syndrome and related diseases such as type II diabetes. People lacking α-actinin-3 rarely play sports that require fast and powerful movements, and in endurance sports they perform better.
“It would be interesting to see how a variety of physical activities affect people with and without α-actinin-3, especially when it comes to protection against metabolic disorders. Finally, it would be interesting to learn more about how people with α-actinin-3 deficiency are exposed to the effects of heat ”, says Prof. M. Brazaitis.
[ad_2]
