Study: People Age Dramatically in Two Waves—First at 44, Then at 60

Scientists have discovered that humans age dramatically in two waves—first at 44, then at 60 years old. The findings, which suggest that aging is not a slow and constant process, could explain the sudden increase in health issues at certain ages, The Guardian says.

If you’ve noticed a sudden increase in wrinkles, aches, or a general feeling of aging almost overnight, there might be a scientific explanation. Research suggests that aging occurs in at least two accelerated phases, rather than as a slow and constant process.

The study, published in Nature Aging, tracked thousands of different molecules in people aged 25 to 75 and detected two major waves of age-related changes around the ages of 44 and 60. These findings could explain why certain health issues, including musculoskeletal problems and cardiovascular diseases, peak at specific ages.

“We don’t gradually change over time. There are some truly dramatic shifts,” said Professor Michael Snyder, a geneticist and director of the Center for Genomics and Personalized Medicine at Stanford University, and the study’s lead author.

“It appears that the mid-40s is a period of dramatic change, as is the early 60s—and this is true no matter what class of molecules you’re looking at.”

The research tracked 108 volunteers, who provided blood, stool samples, and skin, oral, and nasal swabs every few months for one to nearly seven years.

The researchers assessed 135,000 different molecules (RNA, proteins, and metabolites) and microbes (bacteria, viruses, and fungi living in the participants’ intestines and on their skin).

The abundance of most molecules and microbes did not change gradually over time. When scientists looked for groups of molecules with the most significant changes, they found that these transformations tended to occur when people were between 40 and 60 years old.

The mid-40s peak in aging was unexpected and initially thought to be the result of perimenopausal changes in women, skewing the results for the entire group.

However, data showed similar changes occurring in 40-year-old men as well.

“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,” said Dr. Xiaotao Shen, a former postdoctoral researcher at Stanford Medical School and the study’s lead author, now at Nanyang Technological University in Singapore.