Human aging speeds up significantly at ages 44 and 60, according to a small study that suggests people in their 40s and 60s experience major physiological changes, potentially linked to age-related diseases. The research, published in *Nature Aging*, found that 81% of over 11,000 molecules measured in the adult body undergo significant changes at these ages. This study focuses on “biological age,” which reflects bodily changes over a lifetime, as opposed to “chronological age.”
The discovery that biological aging accelerates at these midlife points could shed light on why certain illnesses, like coronary artery disease, become more prevalent as chronological age increases. For instance, while 6.5% of people aged 40-59 have coronary artery disease, this figure jumps to 19.8% for those aged 60-79.
Researchers at Stanford University recruited 108 participants from diverse backgrounds, aged 25 to 75. Over several years, blood samples were collected every three to six months to track changes in gene activity, blood sugar levels, and other factors. Many changes observed around ages 44 and 60 were related to heart health, including increased levels of a protein associated with atherosclerosis and decreased ability to metabolize caffeine and alcohol. The body’s pathway for producing unsaturated fatty acids, which reduce “bad” cholesterol, also weakened at these ages.
Although these findings were correlative, they suggest why heart disease and other conditions may become more common with age. The study also noted that blood sugar levels peaked in participants in their 40s and 60s, hinting at a connection to type 2 diabetes. However, the reasons behind these significant shifts in body chemistry remain unclear, and lifestyle factors like diet and exercise were not accounted for.
Juan Carlos Verján, an aging researcher not involved in the study, speculates that inflammation might be a factor, especially since participants over 60 had higher levels of antioxidant enzymes, which combat inflammation. The study also found that both men and women experienced aging accelerations at the same ages, suggesting a shared, yet unidentified, trigger.
The study had limitations, including its small sample size and the specific age range of participants. Additionally, the focus on blood molecules may not fully represent changes occurring in other organs. More research, including animal studies, is needed to determine whether these biological changes directly cause age-related diseases or are merely byproducts of the aging process.
