Body’s physical decline starts at 34, study suggests

The human body begins a measurable physical decline at age 34, with further significant shifts in the ageing process occurring at 60 and 78, new research suggests.

Rather than progressing steadily, the findings indicate ageing accelerates in phases, driven by changes in specific proteins found in the blood.

The study identified three major ageing milestones – 34, 60 and 78 – marking transitions between adulthood, late maturity and old age.

Researchers analysed blood plasma from more than 4,200 healthy volunteers aged 18 to 95. From a large subgroup, they developed a “proteomic clock” – a tool that estimates biological age by tracking protein levels.

According to the National Institute of Ageing, the clock was able to accurately predict the chronological age of the remaining 1,446 participants within a defined range, using 373 of nearly 3,000 proteins examined.

The clock was also tested on four separate groups not involved in the initial study and correctly predicted participants’ chronological age in each case. Remarkably, accurate estimates could be made using only nine of the most informative proteins.

The researchers found that individuals whose protein profiles suggested they were biologically younger than their actual age also performed better on physical and cognitive tests.

“The results suggest the potential for developing a blood test that can identify individuals who are biologically ageing faster than others,” the researchers said. “Such individuals may face increased risks of age-related health complications including cardiovascular issues, Alzheimer’s disease and osteoarthritis earlier in life.”

The researchers said the findings could pave the way for treatments designed to slow the proteomic clock, potentially helping people stay biologically younger than their actual age. In previous work, the same team demonstrated that transfusing blood from young mice into older ones had a rejuvenating effect.

They noted that the first major ageing surge, at age 34, was particularly striking because it occurs well before typical signs of ageing or related health problems usually appear. The period from 34 to 60 was defined as adult life, 60 to 78 as late maturity, and after 78 as old age.