This effect, which had already been observed in men from Western countries, could be universal, according to the results of a study carried out with members of the Chimané indigenous people and published in the journal Proceedings of the Royal Society B.
The Chimané (Bolivia) are a population of 15,000 people spread over small towns in the Amazon that live from agriculture and hunting. Its inhabitants suffer from various infections and respiratory and gastrointestinal diseases, which is why their immune system is very weakened. Because of this, the Chimané secrete less testosterone. "This hormone is very expensive in energy and is also thought to interfere with the immune system," explains Benjamin Trumble, from the University of Washington (Seattle, USA) and author of the study.
The researchers measured the testosterone levels in the study participants before and after they played a soccer game. Although the starting levels were lower than the average values for Americans, at the end of the game they increased by 30 percent, an amount similar to what other studies have measured in US citizens. In addition, the top scorers in the match experienced the most significant increases in testosterone . "The results confirm that there are more factors explaining the hormonal spike than just participating in the competition," says Trumble.
This work will help to understand the mechanisms of hormonal regulation in the short and medium term, and will give clues on how to treat problems of low testosterone production in older people.
