UNT Health researcher Scott Maddux studies how the human body adapts to extreme environments
At UNT Health Fort Worth, researchers are stepping inside a climate-controlled chamber
to answer a question scientists have debated for more than a century: How does the
human body adapt to different environments?
Dr. Scott Maddux, associate professor and interim director of the Center for Anatomical Sciences, is leading research that examines how anatomy and physiology work together to regulate body temperature in extreme conditions.
“We’ve measured people for decades and made assumptions about why bodies look the way they do,” Maddux said. “Now we finally have the tools to test whether those ideas are actually true.”
From curiosity to climate science
Maddux’s path to human evolution began unexpectedly during his undergraduate years at Texas A&M University, when an introductory anthropology course sparked a lasting interest.
“I took a class on human evolution and just fell in love with it,” he said. “I knew that’s what I wanted to do for the rest of my life.”
His research later evolved to focus on thermoregulation — how the body maintains its internal temperature — and the role anatomy plays in that process. The human nose, for example, plays a critical role in heating and humidifying the air we breathe to protect the lungs.
Inside the climate chamber
At the Human Thermoregulation Laboratory, Maddux, along with collaborator Dr. Elizabeth Cho, and their team use a specialized environmental chamber that can precisely control temperature and humidity. Participants are exposed to a range of conditions, from dry heat exceeding 110 degrees Fahrenheit to humid environments and cold temperatures around 40 degrees.
While inside, participants are outfitted with sensors that track respiration, heart rate, metabolism and temperature. Some even swallow small thermometer capsules that transmit core body temperature data in real time.
The goal is to measure how different body types respond to environmental stress, something that has rarely been studied in combination.
“Physiologists measure how the body responds, and anatomists study body structure,” Maddux said. “But very few people are doing both at the same time. That’s what makes this work unique.”
Testing long-held theories
For decades, scientists have observed patterns in body shape across climates. Populations in warmer regions tend to have longer, leaner bodies that help dissipate heat, while those in colder climates are often shorter and more compact, which helps conserve warmth.
But until recently, these ideas were largely theoretical.
“We’ve been working under these assumptions for years,” Maddux said. “We just want to show that it actually works the way we think it does.”
Early findings suggest the body is highly effective at protecting its core temperature. Instead of large changes internally, researchers are seeing significant shifts in how the body responds externally, such as sweating or changes in skin temperature.
“The core stays remarkably stable,” Maddux said. “It’s everything else that changes to protect it.”
Why it matters
Beyond evolutionary science, the research has real-world implications.
As global travel increases, people are more frequently living in environments very different from those their bodies adapted to over generations. This can create what researchers call “evolutionary mismatches,” potentially increasing risks for conditions like heat stress or respiratory illness.
Understanding these differences could help inform public health strategies, workplace safety guidelines and even military preparedness in extreme climates.
“Thermoregulation is essential for survival,” Maddux said. “If you can’t regulate your body temperature, there are serious consequences.”
Looking ahead
After several years of data collection, the team is now analyzing results from a large-scale study involving more than 100 participants, significantly larger than most studies in the field.
Maddux is also excited about the next generation of researchers contributing new ideas and technologies to their work.
“The most exciting part is seeing students get involved and bring fresh perspectives.” He said. “There’s still so much left to discover.”