Frailty is a serious problem for many older adults because it makes them more vulnerable to bad health outcomes.
People who become frail are more likely to fall, spend longer in the hospital, and even have shorter life expectancy.
A new study suggests that one important way to protect against the dangers of frailty later in life may come from something unexpected: keeping the body’s natural hormone system intact.
The study was carried out by scientists at the Gerald P. Murphy Cancer Foundation’s Center for Exceptional Longevity Studies, a research institute focused on cancer and aging located at Purdue Research Park in Indiana.
Their findings were published in the journal Scientific Reports. While many previous studies have explored what causes frailty to develop, very few have looked at why some older individuals seem to be more resilient once frailty occurs.
This new research focuses on the body’s HPG axis—the system that regulates testosterone and other reproductive hormones—and how it influences survival du…
According to senior author David J. Waters, DVM, Ph.D., the study is the first to describe how the strength of the HPG axis relates to mortality risk in frail older male dogs.
The researchers found that male dogs that had the shortest lifetime exposure to their testes had a very high risk of death once they became frail. In contrast, the dogs that kept their testicular function the longest did not experience the same rise in mortality risk, even when their frailty increased.
These findings point to an important question: Are there certain parts of the body’s physiology that help reduce the harm caused by frailty? And if so, could protecting hormone function be one of the keys to healthier aging?
Waters believes so. “On the basis of our findings, we propose that HPG axis function is an important regulator of the impact of late-life frailty,” he explained. The idea is that the hormones produced by the gonads may help buffer the body from some of the damage associated with aging, even when frailty is already present.
Markus H. Schafer, Ph.D., a professor of sociology at Baylor University and co-author of the study, explained that the approach was unique because it used a life‑course perspective. Instead of looking only at what happens late in life, the researchers examined how early-life events—such as hormone removal—can influence resilience decades later.
Schafer noted that his own work in sociology shows how social connections can buffer feelings of loneliness. This study, he said, shows how biological systems may also provide buffering effects.
The study stands out because it involved contributions from multiple scientific fields. Kenneth Ferraro, Ph.D., a distinguished professor at Purdue University, praised the interdisciplinary nature of the work.
Experts in veterinary medicine, sociology, nutritional science, exercise science, and comparative medicine all contributed to the project. Many of the co-authors earned their Dual‑Title Ph.D. in Gerontology from Purdue, the first university in the U.S. to award this type of degree.
A key part of this research came from an unusual source: some of the oldest-living dogs in North America. Waters leads the Exceptional Aging in Rottweilers Study, which focuses on companion dogs that have lived far longer than the average lifespan of their breed.
These exceptional dogs, equivalent to 100‑year‑old humans, provide valuable insights into healthy aging. Researchers gather lifetime medical histories from owners through interviews, questionnaires, and veterinary records. In this study, the scientists used this unique long‑term dataset to examine the relationship between lifetime testis exposure, frailty levels, and survival.
The findings build on earlier work linking ovaries to longevity in female dogs and research showing how early hormone disruption affects ligament health.
These new results challenge long‑held beliefs about the health consequences of spaying and neutering in companion animals by showing that lifetime hormone exposure may play a more important role in aging than previously thought.
Waters noted that dogs have contributed to major scientific discoveries before, including the discovery of insulin and the early development of prostate cancer treatments. Because of this history, he believes that the exceptional aging seen in some dogs can help scientists better understand how hormonal systems influence healthy aging.
“Our work suggests that avoiding deterioration of the HPG axis may help retain an internal hormonal environment that protects the body from the harmful effects of frailty,” he said.
As scientific interest in canine research grows, Waters sees these long‑lived dogs as important partners in the search for new answers about aging. “We’ve identified a special group of dogs that can help inform future research directions,” he said. “Our message to these dogs should be a simple one: We’re ready to listen.”
If you care about wellness, please read studies about nutrients that could combat inflammation in older people, and essential foods for healthy aging.
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