Chopping wood may be the manliest sport there is.
According to a new study, the act of chopping wood produces more testosterone than competitive activities like sports. The discovery highlights how testosterone isn’t only associated with competition and aggression, the Australian Broadcast Corporation reports.
The study, which was published in Evolution and Human Behavior, analyzed saliva from Bolivian forager-farmers, known as the Tsimane, collected after they played soccer and after they chopped down trees in the Amazon jungle to grow crops. Chopping down trees resulted in a 48 percent increase in salivary testosterone compared to only a 30.1 percent increase after playing a game of soccer.
“One of the important take-home messages of this study is that over the course of human evolution, we had very physical strategies for producing calories. It’s important to think about how testosterone fits into that,” Dr. Ben Trumble of the Institute of Social, Behavioral and Economic Research said, explaining that testosterone levels are related to the food's energy. That is, when men skip a meal, their testosterone levels can drop as much as 10 percent, he said.
“The same is true for infection,” he added. “An infection from a pathogen or parasite –-- even injuries, burns, or surgery –-- all cause an immediate decrease in testosterone.”
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The Tsimane's primitive life style, which includes hunting and gathering food, differs greatly from Western lifestyles.
“For populations in industrialized countries like the United States, there isn’t much of a tradeoff,” Trumble said. “I can go to the grocery store and gather 20,000 calories in 10 minutes without breaking a sweat. I don’t have to worry about a deficit.”
But for Tsimane men, life is different.
“If you’re a 50-year-old Tsimane man, for example, you probably have six or more children, and you need to be able to feed them,” Trumble explained. “If you lose the ability to have the acute spikes in testosterone that increase your ability to chop trees -- chop longer and chop harder -- that would be detrimental to feeding your family.”
And unlike men from the United States who experience a decrease in testosterone levels with age, Tsimane men maintain the same testosterone levels over the course of their lives.
"Even late in life, these men can express the same spikes in testosterone as younger men," Trumble said.