Why aging seems to speed up around 50

A team from the Chinese Academy of Sciences reports that the body’s aging process hits a turning point around age 50.

By examining changes in proteins in people of varying ages, researchers found that around 50, tissues and organs begin to age more rapidly and noticeably than in earlier decades. Blood vessels showed some of the fastest signs of wear.

“Based on the changes in proteins associated with aging, we developed a specific biological clock and described the aging trajectories at the organ level. Our temporal analysis revealed a turning point in aging—around 50 years. Blood vessels are particularly prone to early aging,” the team wrote.

“Our findings lay the groundwork for a systematic understanding of human aging through the lens of proteins,” they said.

What Did the Researchers Discover?

Science still doesn’t fully understand how individual organs age. So the researchers looked at how proteins in different tissues change over time. They collected tissue samples from 76 organ donors, ages 14 to 68, who died from accidental traumatic brain injuries.

The samples covered seven body systems: cardiovascular (heart and aorta), digestive (liver, pancreas, and intestines), immune (spleen and lymph nodes), endocrine (adrenal glands and white adipose tissue), respiratory (lungs), integumentary (skin), and musculoskeletal (muscles). The researchers also analyzed blood samples.

The team compiled a catalog of proteins identified in these systems and tracked how those proteins changed as the donors aged. By comparing their results with a database of diseases and related genes, the researchers found that the expression of 48 proteins associated with disease increased with age.

This pattern mainly involved cardiovascular disease, tissue fibrosis, fatty liver disease, and liver tumors.

The most pronounced proteomic changes occur between ages 45 and 55. During this window, many tissues undergo significant proteomic remodeling—changes in protein composition. The aorta showed the clearest signs of aging, suggesting high vulnerability; the pancreas and spleen also displayed notable changes, according to ScienceAlert.

To test their findings, the researchers isolated an aging-related protein from the aorta of older mice and introduced it into younger mice. Treated rodents showed declines in physical performance, grip strength, and endurance, along with worse balance and coordination, compared with untreated mice. They also displayed clear markers of vascular aging.

Why Is This Work Important?

Previous studies identified other aging peaks, around ages 44 and 60. These new results support the idea that human aging is complex and occurs in stages that affect different body systems at different times. Knowing which organs change at particular ages could help guide medical interventions to slow or mitigate those effects.

“Our research aims to create a comprehensive proteomic atlas that maps the aging process over five decades; it will help identify the mechanisms behind proteostasis imbalance in aging organs and reveal both universal and tissue-specific aging patterns,” the authors wrote.

“That knowledge could inform targeted strategies to fight aging and age-related diseases, paving the way for better health in later life,” they added.

The study was published in the journal Cell.

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