CBTS student earns multiple grants to support human thermoregulation research
As the summer heat sets in, you might be more keenly aware of your body’s ability
to regulate its temperature. Typically, your skin gets all the credit for keeping
you cool through processes like sweating or vasodilation. But there’s another part
of your body that might play a larger role in regulating temperatures – your nose.
Baonhu Tran, a PhD candidate at UNT Health Fort Worth’s College of Biomedical and Translational Sciences, has focused her dissertation research on the topic, specifically how the size and shape of your nose might play an important role in how your brain and body regulate heat.
“Historically, a lot of research into human thermoregulation has focused on the role of the skin and not much has focused on the respiratory system, especially the nose,” Tran said.
“Because we are constantly breathing out warm air, the respiratory system may contribute more to thermoregulation in certain environments than previously thought. My goal is to revisit this question and see whether the respiratory system plays a larger role in some climates and a smaller role in others.”
The project is being conducted in two phases. First, Tran and the research team are looking at the role of the respiratory system in whole body thermoregulation.
“The literature suggests that the respiratory system contributes only about ten percent of total heat loss, while the skin accounts for the majority of heat exchange with the environment. However, lot of those experimentshave been conducted under room temperature conditions,” Tran said. “If we factor in different climates, temperatures and humidities, the respiratory system may play a more important role in temperature regulation than previously assumed.”
To gather data, Tran is using some high-tech tools including the climate chamber at UNT Health’s Center for Anatomical Sciences. Research subjects spend time in chamber set to replicate the climates of the Sahara desert, the Arctic tundra and the Amazon rainforest to test how the body regulates heat in those conditions. Through a partnership with JPS Health Network, the team conducts CT scans on each research participant. For her dissertation project, Tran is using the CT scans to get accurate measures of their nasal passages.
“Taller, narrower noses tend to be better at heating and humidifying inspired air because there is increased nasal mucosa surface area in the nasal passages. This allows for better transfer of heat and moisture to helpwarm and humidify that air upon contact with the nasal mucosa,” Tran said.
However, Tran says that shorter and wider noses may help the body shed heat in hot, humid tropical climates.
“If we think about the climate there, the air is already pretty hot with more moisture, so there is not as much of a need to transfer heat and moisture to that air during inspiration. However, during exhalation, hot air is always breathed out. This may help with body temperature regulation in those conditions,” Train said.
She’s using some low-tech approaches as well, like a 1993 HVAC engineering handbook she bought on eBay. While preparing for her project, she found the American Society of Heating, Refrigerating and Air-Conditioning Engineers Handbook was full of industry-standard mathematical models that help calculate things like respiratory heat loss and body temperature regulation.
“I'm essentially putting the variables we’ve collected into established equations to calculate how much the respiratory system is contributing to overall body temperature regulation for each participant during their exposures in the climate chamber,” Tran said.
“I didn't realize I would be doing this much math when I started my PhD, but it’s been fun.”
The second phase of the project will explore the role of the nose in brain thermoregulation, an area of research that hasn’t previously gotten much attention. In that study, the team will use microwave radiometry, a non-invasive way to detect thermal radiation to accurately measure brain temperatures with the goal of determining how the respiratory system might play a role in regulating brain temperature in different climates.
Tran, who took an interest in researching nasal passages while she was an undergraduate
intern at UNT Health’s Summer Opportunities in Anatomy Research program, is getting
some major support for her work. She earned grants to fund her research from the National Science Foundation, the Leakey Foundation and the Wenner-Gren Foundation. Additionally, Tran was accepted to the NSF Graduate Research
Fellowship Program, which supports outstanding graduate students who demonstrate the
potential to make significant contributions in STEM. Tran is the first UNT Health
student to be accepted to the fellowship program.
“The fact that Baonhu’s research was funded by all three of the major anthropological funding agencies speaks to the originality and importance of her research project,” said Dr. Scott Maddux, Tran’s research mentorand interim director of the Center for Anatomical Sciences at UNT Health.
“Her NSF review panel probably summarized it best: ‘The panel was impressed by the high likelihood of the proposal to provide new foundational (textbook) knowledge of how human thermoregulation works.’”
On top of answering long-standing questions about the role of the respiratory system and body temperature regulation, Tran’s findings could also have real-world impacts in areas such as athletic performance, occupational hazards and public health.
“With climate change happening now and into the future, if we have a better understanding of thermoregulation in different climates and how the nose contributes to it, then we can provide better insight into how to keep people healthy and comfortable,” Tran said.
This material is based on work supported by the U.S. National Science Foundation under awards No. 2444956 and 2521817. Any opinions, findings, conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the U.S. National Science Foundation.