Researchers with Stanford University have published a study revealing that physical aging is not a smooth process, but rather something that happens in what they describe as a ‘herky-jerky trajectory.’ Using blood tests to look at specific proteins, the researchers found that human aging involves three distinct turning points, the first starting in one’s mid-thirties.
Proteins in the blood can provide clues about a person’s health and, according to the new study, show changes that allow researchers to estimate a person’s age. The study found that the levels of many proteins in the blood change with age — something that may cause, rather than just reference, the process of physically aging.
The study involved blood plasma from more than 4,200 people ages 18 through 95. Based on their analysis of protein changes, the researchers found that humans experience multiple ‘distinct times’ when protein levels experience pronounced ‘changes in abundance,’ something found to happen at around the ages of 34, 60, and 78 years.
Using a formula based around these proteins, the researchers say they can estimate someone’s age with an accuracy of within a three-year range. The times when the formula failed by estimating someone as younger than they were pointed toward the presence of particularly remarkable health. As well, the researchers found that a significant number of proteins showed changes that differed based on sex.
The findings ‘strongly support’ that men and women age differently, underscoring the need to include women in clinical trials and to note participants’ biological sex as a factor in research.
The researchers explain that in the future, looking at protein levels in blood may be able to reveal when a person is aging much faster than expected, helping doctors intervene in the potential development of health issues like dementia. As well, the findings may help experts develop new ways to slow down aging.