A groundbreaking study by Professor Lewis Halsey of the University of Roehampton provides fascinating insights into how the human body responds to rising temperatures and intense heat. This discovery has enormous implications for a variety of industries, including the work environment, sports, medical practices and international travel.
Professor Halsey’s research revealed the existence of an upper critical temperature (UCT) for humans, which is somewhere between 40°C and 50°C. This means that when this temperature is exceeded, the metabolic energy expenditure of the human body begins to rise in response to extreme heat. This discovery is a watershed moment in understanding the body’s response to extreme temperatures.
Metabolic rate and its response to different conditions are complex research questions. At rest, the metabolic rate, that is, the amount of energy needed to keep the body functioning normally, can increase dramatically when the environment is hot and humid. This means that the human body begins to expend more energy to maintain its temperature in hot conditions.
Professor Halsey notes that many studies have been done on the range of temperatures at which different animal species prefer to live in terms of their minimum metabolic rate. However, information about the upper limits of the thermally neutral zone in humans has been much less available. Professor Halsey’s study fills this knowledge gap and provides fundamental insights into how the human body responds to suboptimal conditions and how these responses may differ in people with different characteristics.
The research has broad implications for a variety of industries. Determining the threshold temperatures at which metabolic rate begins to increase can help create a more comfortable and safer work environment. In sports, knowledge of the body’s response to high temperatures can help athletes optimize their training and achieve better results. In medical practice, understanding the body’s response to extreme temperatures can be useful in treating patients with heatstroke or other heat-related illnesses. For international travelers, knowing the upper limits of the thermal neutral zone can help avoid problems related to adapting to new climatic conditions.
The research team is also investigating how extreme temperatures exceeding the GTC affect heart function and how these effects differ in people with different characteristics, such as age and physical fitness. Professor Halsey notes that significant differences in cardiovascular responses have been found between men and women at high levels of heat.
To conduct the study, the team used an advanced echocardiograph, which allows detailed images of heart function. This is unusual research equipment, which is usually used in hospitals but rarely in research laboratories. It provided accurate data on the heart’s response to elevated heat.
Professor Halsey’s research is ongoing, and he plans to present the latest results at the Society for Experimental Biology conference. In a world where climate change is becoming increasingly prominent, this knowledge about the body’s response to heat stress is even more valuable.