A study from the University of Ottawa’s Human and Environmental Physiology Research Unit (HEPRU) has confirmed that the limits for human thermoregulation—our ability to maintain a stable body temperature in extreme heat—are lower than previously thought.
This research, led by Dr. Robert D. Meade, former Senior Postdoctoral Fellow and Dr. Glen Kenny, Director of HEPRU and professor of physiology at uOttawa’s Faculty of Health Sciences, highlights the urgent need to address the impacts of climate change on human health.
The study found that many regions may soon experience heat and humidity levels that exceed the safe limits for human survival. “Our research provided important data supporting recent suggestions that the conditions under which humans can effectively regulate their body temperature are actually much lower than earlier models suggested,” states Kenny. “This is critical information as we face increasing global temperatures.”
Utilizing a widely used technique known as thermal-step protocols, Meade and his team exposed 12 volunteers to various heat and humidity conditions to identify the point at which thermoregulation becomes impossible. What made this study different, was that participants returned to the laboratory for a daylong exposure to conditions just above their estimated limit for thermoregulation. Participants were subjected to extreme conditions, 42°C with 57% humidity, representing a humidex of approximately 62°C. “The results were clear. The participants’ core temperature streamed upwards unabated, and many participants were unable to finish the 9-hour exposure. These data provide the first direct validation of thermal step protocols, which have been used to estimate upper limits for thermoregulation for nearly 50 years”, says Meade.
“Our findings especially timely, given estimated limits for thermoregulation are being increasingly incorporated into large scale climate modelling” explains Meade. “They also underscore the physiological strain experienced during prolonged exposure to extreme heat, which is becoming more common due to climate change.”
The implications of this research extend beyond academia. As cities prepare for hotter summers, understanding these limits can help guide health policies and public safety measures. “By integrating physiological data with climate models, we hope to better predict and prepare for heat-related health issues,” adds Kenny.
As the world grapples with the realities of climate change, this research aims to spark important conversations about our safety and adaptability in increasingly extreme environments.
For more information, read the study titled “Validating new limits for human thermoregulation”, published in the Journal PNAS.
Journal
Proceedings of the National Academy of Sciences
DOI
10.1073/pnas.2421281122
Method of Research
Meta-analysis
Subject of Research
People
Article Title
Validating new limits for human thermoregulation
Article Publication Date
31-Mar-2025
Media Contact
Bernard Rizk
University of Ottawa
Journal
Proceedings of the National Academy of Sciences
DOI
10.1073/pnas.2421281122
Journal
Proceedings of the National Academy of Sciences
DOI
10.1073/pnas.2421281122
Method of Research
Meta-analysis
Subject of Research
People
Article Title
Validating new limits for human thermoregulation
Article Publication Date
31-Mar-2025
Keywords
/Life sciences/Physiology/Homeostasis/Body temperature/Body temperature regulation
bu içeriği en az 2000 kelime olacak şekilde ve alt başlıklar ve madde içermiyecek şekilde ünlü bir science magazine için İngilizce olarak yeniden yaz. Teknik açıklamalar içersin ve viral olacak şekilde İngilizce yaz. Haber dışında başka bir şey içermesin. Haber içerisinde en az 12 paragraf ve her bir paragrafta da en az 50 kelime olsun. Cevapta sadece haber olsun. Ayrıca haberi yazdıktan sonra içerikten yararlanarak aşağıdaki başlıkların bilgisi var ise haberin altında doldur. Eğer yoksa bilgisi ilgili kısmı yazma.:
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Keywords
Tags: body temperature stability in heatclimate change impacts on healtheffects of global warming on healthextreme heat exposure studyheat and humidity survival limitshuman health and climate crisishuman heat tolerance thresholdshuman physiology and temperature regulationthermal-step protocols in researchthermoregulation limits in extreme heatUniversity of Ottawa research studyurgent need for climate action in health
