Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


UCSB anthropologists study testosterone spikes in non-competitive activities

The everyday physical activities of an isolated group of forager-farmers in central Bolivia are providing valuable information about how industrialization and its associated modern amenities may impact health and wellness.

Studying short-term spikes in the testosterone levels of Tsimane men, UC Santa Barbara anthropologists Ben Trumble and Michael Gurven have found that the act of chopping down trees –– a physically demanding task that is critical to successful farming and food production –– results in greater increases in testosterone than does a directly competitive activity such as soccer. Their research appears in the early online edition of the journal Evolution and Human Behavior.

A new study finds Tsimane men experience higher short-term testosterone spikes while chopping trees than they do playing competitive soccer.

Credit: Benjamin C. Trumble

"With the Tsimane, we see an environment that is more like that in which humans evolved, and for which our systems are calibrated," said Trumble, a postdoctoral researcher in anthropology at UCSB and the paper's lead author. The paper was written with Gurven, a UCSB professor of anthropology and co-director of the Tsimane Health and Life History Project, a collaboration between UCSB and the University of New Mexico.

According to Trumble, whose research lies at the intersection of hormones, behavior, and the environment, testosterone levels are closely related to the availability of food energy. When young men skip even a single meal, their testosterone levels can drop as much as 10 percent. Fast for a couple of days, and they decrease to castrate levels.

"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."

The body uses food energy for a number of critical processes. Among them are building muscle mass and maintaining proper immune function. When food energy is limited, the body has to choose between one and the other. 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."

However, for a group such as the Tsimane, who are more physically active than most Americans –– and use a lot more food energy –– but also have to grow, hunt, or fish for the vast majority of the calories they consume, the tradeoff is much greater. In addition, the Tsimane's regular exposure to pathogens and parasites requires additional calories for maintaining necessary immune function.

Previous studies by Trumble, Gurven, and others have demonstrated that competitive activity –– such as soccer –– causes a short-term spike in testosterone. "Past research has mostly focused on the role of testosterone in aggressive competition," Trumble said. "Given the important of testosterone in supplying energy to muscles, we wanted to look at how testosterone changes during another vital part of Tsimane life –– food production." He and the research team collected saliva specimens from Tsimane men before and after an hour of tree chopping, just as previous studies had examined saliva specimens taken from Tsimane men immediately before and after an hour of soccer. "With soccer, we saw a 30.1 percent increase in testosterone," Trumble said. "With chopping, we saw a 46.8 percent increase. It was significantly greater."

The acute spike in testosterone increases the muscle's ability to take in blood sugar, which, in turn, enhances soccer performance and reaction times. It turns out the same is true for tree chopping. "If you're better able to pull blood sugar into your muscle tissue, and better able to use that energy, you'll be able to chop more trees," Trumble explained.

While Tsimane men have a relatively low baseline testosterone level –– 33 percent lower than that of men living in the United States, where life is less physically demanding –– they appear to maintain their testosterone levels over the course of their lives. This is contrary to the United States and other industrialized populations, where men generally experience decreases in testosterone as they age.

"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. We needed to maintain testosterone in order to maintain muscle mass, and also to spike testosterone when necessary. 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. 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."

Trumble noted that in many societies women produce a significant portion of calories, and other researchers have reported acute spikes in testosterone during physical activity for women, despite their very low baseline levels. "While we didn't measure the testosterone of women in this study, women can also produce short-term spikes, which suggests the importance of acute rises in testosterone not only for competition over mates, but also for critical daily tasks such as food production."

The paper's other co-authors include Hillard S. Kaplan and Daniel K. Cummings of the University of New Mexico, Albuquerque; and Kathleen A. O'Connor, Darryl J. Holman and Eric A. Smith of the University of Washington, Seattle.

Andrea Estrada | EurekAlert!
Further information:

More articles from Studies and Analyses:

nachricht Diagnoses: When Are Several Opinions Better Than One?
19.07.2016 | Max-Planck-Institut für Bildungsforschung

nachricht High in calories and low in nutrients when adolescents share pictures of food online
07.04.2016 | University of Gothenburg

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Resolving the mystery of preeclampsia

21.10.2016 | Health and Medicine

Stanford researchers create new special-purpose computer that may someday save us billions

21.10.2016 | Information Technology

From ancient fossils to future cars

21.10.2016 | Materials Sciences

More VideoLinks >>>