Why Older People Should Chill When it’s Hot Out? (Biology)

Cooling off during extreme heat appears to help preserve cellular defenses

Taking a break from extreme heat, by visiting a cooling center for example, could help our cells protect themselves from damage, according to preliminary findings from a new study. The research, which focused on older people, suggests temporarily cooling down on a hot day helps cells maintain autophagy, a process cells use to rid themselves of dangerous protein buildups caused by stressors like extreme heat.

“By lessening the time spent in a state of elevated internal body temperature, cooling centers may help to preserve autophagy in older adults, which may translate to greater cellular protection and improved health outcomes during an extreme heat event,” said James J. McCormick, PhD, a postdoctoral fellow at the Human and Environmental Physiology Research Unit of the University of Ottawa in Canada, and the study’s first author.

McCormick will present the research at the American Physiological Society annual meeting during the Experimental Biology (EB) 2021 meeting, held virtually April 27-30.

Sustained elevations in internal body temperature can lead to heat stroke, cardiovascular events and kidney failure. Older people are particularly vulnerable since the body’s systems for regulating temperature degrade as we age.

A researcher pipettes blood samples to measure markers of autophagy, a defense mechanism cells use to protect themselves from damage. © James McCormick, University of Ottawa.

During periods of extreme heat, health agencies recommend that people without home air conditioning spend a few hours in a cooled location, such as a cooling center or heat-relief shelter. However, there has been little research into how visiting a cooling center actually affects the physiological processes associated with heat exposure.

“With climate change, the global population is increasingly exposed to protracted periods of extreme heat,” said Robert D. Meade, a doctoral candidate who is part of the research team. “Prolonged exposure to hot temperatures can overwhelm the body’s ability to cool itself, particularly in older adults. Thus, there is a crucial need to develop evidence-based guidance for protecting older adults from extreme heat.”

The researchers analyzed how older people responded to a simulated heat wave with and without a cooling break. A total of 17 volunteers spent nine hours in a room heated to 40° C (104° F). In the middle of the day, seven of the volunteers had a two-hour break in a room that was a comfortable 23° C (73° F).

While the cooling break did not result in lasting reductions in participants’ core body temperature, these participants did show improved markers of autophagic function compared to the group that endured high heat for the full nine hours. The findings suggest that visiting a cooling center could help older people avoid some of the cellular damage that may contribute to serious health impacts of heat exposure, according to researchers.

The researchers plan to conduct further studies to determine whether other cooling strategies, such as using a fan, could also help to preserve autophagic function in older adults.

McCormick will present this research in poster R3744 (abstract). Contact the media team for more information or to obtain a free press pass to access the virtual meeting.

Featured image: A volunteer in the test chamber used for the research. The chamber is heated to simulate a heat wave while devices continually monitor whole-body heat exchange. © James McCormick, University of Ottawa.


Provided by American Physiological Society


About Experimental Biology 2021

Experimental Biology is an annual meeting comprised of thousands of scientists from five host societies and multiple guest societies. With a mission to share the newest scientific concepts and research findings shaping clinical advances, the meeting offers an unparalleled opportunity for exchange among scientists from across the U.S. and the world who represent dozens of scientific areas, from laboratory to translational to clinical research. http://www.experimentalbiology.org 

About the American Physiological Society (APS)

Physiology is a broad area of scientific inquiry that focuses on how molecules, cells, tissues and organs function in health and disease. The American Physiological Society connects a global, multidisciplinary community of more than 10,000 biomedical scientists and educators as part of its mission to advance scientific discovery, understand life and improve health. The Society drives collaboration and spotlights scientific discoveries through its 16 scholarly journals and programming that support researchers and educators in their work. http://www.physiology.org

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