Older adults lose cold resistance because thermogenic fat grows sluggish over time, according to new research published in Nature.
Unlike white fat that stores energy, thermogenic fat burns calories to keep the body warm. This specialized tissue becomes less active as people age.
Researchers from City of Hope uncovered the biological mechanism behind this shift. Signals from nerves and immune cells regulate how much heat thermogenic fat produces by balancing active and inactive cells.
Experiments in mice show this system loses flexibility with age. The tissue takes longer to respond when temperatures drop.
Thermogenic fat cells vary in heat output. Some cells contain high levels of the heat-generating protein UCP1, while others remain largely dormant.
This mix allows the body to adjust to changing temperatures. Nervous and immune systems prompt dormant cells to generate warmth when needed.
Older mice showed a sluggish response during cold exposure. While their thermogenic fat still increased heat production, the delay made body temperature regulation difficult.
“Learning how the body controls this process may offer insights into obesity, type 2 diabetes and other metabolic disorders,” said Qiong “Annabel” Wang, Ph.D., an associate professor at City of Hope’s Arthur Riggs Diabetes & Metabolism Research Institute and corresponding author of the study.
Researchers restored some heat production in older mice by blocking part of the biological pathway responsible for the slowdown. Treated animals burned more energy and produced more heat.
The experiment utilized mifepristone, a drug that affects multiple body systems. Scientists stress that mifepristone is not a treatment for age-related cold sensitivity.
Wang said that metabolic health is affected beyond simply staying warm. Thermogenic fat actively burns glucose and fat alongside its primary heating function.
“If scientists can find a safe, precise way to restore that activity, this foundational research could eventually deepen our understanding of age-related metabolic problems, including obesity and type 2 diabetes,” Wang said.
Thermogenic fat becomes less active and slower to respond to temperature drops with age. This reduction limits the body’s natural ability to generate internal heat.
Researchers successfully restored heat production in older mice by blocking specific biological pathways. However, safe treatments for humans remain in the early research phase.
Thermogenic fat also burns glucose and fat to produce heat. Scientists study its decline to better understand metabolic disorders like obesity and type 2 diabetes.
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