Physical activity places a significant demand on the human body, making it important to understand how it responds to intense exercise. This knowledge can help improve performance and reduce the risk of illness for those in physically demanding jobs such as firefighting, law enforcement, and sports. A new study by led by Dr. Justin Teeguarden and Dr. Kristin Burnum-Johnson from the Pacific Northwest National Laboratory explores how the body adapts to physical exertion. Their findings, published in the journal Military Medical Research, examine the biological changes that occur during intense exercise.
Dr. Teeguarden and Dr. Burnum-Johnson analyzed blood, urine, and saliva samples from a group of wildland firefighters before and after a demanding workout lasting less than an hour. They identified thousands of different proteins, which are molecules that perform essential functions in the body; fats, which store energy; and small molecules that help regulate body functions. This analysis revealed key patterns related to tissue damage, energy use, and immune system responses. “Our study highlights how the body works to stay balanced and adapt during intense physical exertion,” said Dr. Teeguarden.
Changes in blood samples showed clear signs of muscle strain and the body’s efforts to repair itself. Higher levels of structural proteins, which provide support to tissues, and factors that promote tissue rebuilding were detected. At the same time, the body shifted how it used fat for energy, preferring to break down shorter, more accessible fatty acids, which are the building blocks of fats. Additionally, the process of converting sugar into energy, known as metabolism, was highly active, helping to meet increased energy demands.
Examining urine samples provided valuable information about how the body maintains hydration, which is the balance of water in the body, and essential nutrients. Scientists noticed an increase in hormone activity, which involves chemical messengers that regulate processes such as blood pressure and fluid levels. This suggests that the body was working to retain water and essential nutrients, which is important for maintaining endurance and preventing dehydration during prolonged exertion.
Looking at saliva samples, the researchers observed unexpected changes in immune activity, which is the body’s defense system against infections. Levels of proteins that trigger inflammation, the body’s natural response to injury or infection, were reduced, while natural antimicrobial substances, which help fight bacteria and viruses, increased. This means that while the body may temporarily suppress inflammation, it strengthens its defenses against infections. However, a review of past research suggests that individuals who engage in intense exercise may be more vulnerable to respiratory infections, likely due to short-term changes in immune function.
Dr. Teeguarden and Dr. Burnum-Johnson’s discoveries provide a deeper understanding of how the body manages stress during high-intensity activity. By learning more about these processes, scientists can develop better strategies to support recovery, enhance performance, and lower health risks for people in physically demanding roles. Future research may focus on targeted approaches such as nutrition, which is the study of food and its impact on health, and recovery techniques, which are methods to help the body heal and regain strength, to help the body adapt more efficiently.
Journal Reference
Nakayasu E.S., Gritsenko M.A., Kim Y.M., Kyle J.E., Stratton K.G., Nicora C.D., Munoz N., Navarro K.M., Claborne D., Gao Y., Weitz K.K., Paurus V.L., Bloodsworth K.J., Allen K.A., Bramer L.M., Montes F., Clark K.A., Tietje G., Teeguarden J., Burnum-Johnson K.E. “Elucidating regulatory processes of intense physical activity by multi-omics analysis.” Military Medical Research, 2023. DOI: https://doi.org/10.1186/s40779-023-00477-5
About the Authors
Dr. Justin Teeguarden is a distinguished scientist specializing in environmental health, toxicology, and human exposure assessment. With extensive experience in biochemical research, he has contributed to understanding how environmental and occupational stressors affect human health. His expertise spans computational modeling, chemical risk assessment, and multi-omics analysis, helping to bridge the gap between laboratory findings and real-world applications. Dr. Teeguarden has been a leading researcher at the Pacific Northwest National Laboratory, where he has played a crucial role in studies on human resilience to physical and environmental stress.
Dr. Kristin Burnum-Johnson is an accomplished biochemist with a focus on systems biology and analytical chemistry. Her work involves using advanced mass spectrometry and molecular profiling to explore how biological systems respond to stress, disease, and environmental changes. As a senior scientist at the Pacific Northwest National Laboratory, Dr. Burnum-Johnson has led groundbreaking research on metabolism, immune responses, and exercise physiology, providing valuable insights into human health and performance.
