It’s not exactly a secret that our bodies continue to change as we age—and not always in a good way. Each year can feel like it brings added aches, pains, health issues, and other signs of getting older as time goes on. But while it might seem like a gradual progression overall, the truth might not be so simple. In fact, new research suggests that the human body will often change the most at two separate times: ages 44 and 60.
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In a new study conducted by Stanford Medicine published in Nature Aging, scientists collected blood and stool samples and nasal and oral swabs from 108 volunteers between the ages of 25 and 75 over the course of several months. The team analyzed samples for more than 135,000 different data points, including molecular elements such as RNA, metabolites, and proteins, and parts of their individual biomes such as bacteria and fungus.
Researchers found that rather than increasing over time, there were two points where participants showed significant changes within the body. Specifically, they appeared to happen around the age of 44 and sometime around their 60th birthday.
“We’re not just changing gradually over time; there are some really dramatic changes. It turns out the mid-40s is a time of dramatic change, as is the early 60s,” senior author Michael Snyder, PhD, geneticist and director of the Center for Genomics and Personalized Medicine at Stanford University, said of the findings in a press release from Stanford Medicine. “And that’s true no matter what class of molecules you look at.”
It also appears that biological sex is not a key factor. While researchers originally attributed the first spike of changes seen in participants in their mid-40s to premenopause in female participants, data also showed that men were undergoing the same transitions.
“This suggests that while menopause or perimenopause may contribute to the changes observed in women in their mid-40s, there are likely other, more significant factors influencing these changes in both men and women,” first author Xiaotao Shen, PhD, a former postdoctoral scholar at Stanford Medicine, said in the press release. “Identifying and studying these factors should be a priority for future research.”
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The study results also suggest that both sets of changes may affect different areas of health. In the study, there were shifts in molecules and biological processes related to immune function and carbohydrate processing during the 60-year transition. During the 40-year transition, there were changes related to cardiovascular disease, lipid metabolism, and alcohol processing.
However, the researchers also pointed out that some of the changes might be more related to behavioral changes than biological causes. For example, the observed shift in alcohol metabolism might be related to a sudden increase in alcohol consumption during a person’s mid-40s, which is often a particularly stressful period, per the press release.
Ultimately, the findings emphasize the importance of monitoring one's health and well-being, especially around the apparently sensitive times observed in the study. They said this could mean focusing on maintaining muscle mass during these periods and trying to lessen alcohol intake in one's mid-40s—but that still doesn’t mean one should wait to get started.
“I’m a big believer that we should try to adjust our lifestyles while we’re still healthy,” Snyder said in the release.
