John Harrell, PhD

I am a research physiologist for the 711th Human Performance Wing of the U.S. Air Force. I perform research on the impact of the aerospace environment on human physiology. I also contribute to the education and training of active-duty U.S. Air Force aerospace physiology officers. Lastly, I occasionally contribute to guidance documents for the Air Force. 

Give it context. Why is your work important? How does it contribute to other efforts? 

Flying a high-performance jet (a.k.a. fighter jet) can simultaneously impose several physiological stressors on pilots. High acceleration, severe hypobaria, dehydration, breathing resistance, heat stress and alterations of inspired oxygen can each degrade human performance. Our research investigates the individual and combined effects of these stressors on pilot health and safety. We aim to maximize pilot performance and prevent mishaps.  

My education and training prepared me to understand multiple physiological systems and consider their integrative nature. Further, it readied me to think about how those systems function to acutely respond and/or chronically adapt to individual and combined homeostatic challenges (e.g., hypobaria, heat, acceleration, exercise). Early in my career I primarily focused on the cardiovascular system. Specifically, our research investigated the impact of metabolic syndrome on cerebral blood flow responses to hypoxia and hypercapnia. Following a couple of geographic relocations to be closer to family, I transitioned from academia to military research by relying on my professional network. My experience provided a solid foundation to grow into my current role easily. Further, I feel I can understand the full scope of physiological challenges of the aerospace environment and their impact on the human body. 

Outside of my day-to-day duties as a research physiologist, I’m inspired by learning, growth and opportunity. Outside of my job entirely, I’m inspired by trying to be a good parent, spouse and member of my community. I’m also inspired by my dad’s growing hobby of woodworking later in his life. I admire his work, and I think I’d like to take it up, as well. It is very difficult to imagine myself in a field not at least adjacent to science. I could envision a career in the medical field (e.g., physician assistant or physician). Applying knowledge of human physiology to maximize human performance in athletics would be interesting. I can also imagine a career in education, but I would likely teach science-based subjects. Lately, I have considered expanding my skill set into data analytics to support the research our group is conducting as our data sets expand.  

John Harrell, PhD, is a research physiologist in the Aerospace Physiology Research Section, 711thHuman Performance Wing of the U.S. Air Force. He has been an APS member since 2019.