We Age Dramatically at 44 and 60

If the mirror has felt a little less kind than usual lately, and you happen to be 44 or 60, science may have just proved you aren't imagining things. A new study published in Nature Aging has found that rather than change at a slow and steady pace, our molecules fluctuated in number in what the Guardian calls "at least two accelerated bursts": at ages 44 and 60. The Washington Post reports the study found 81% of molecules significantly changed in number around those two ages. As lead author Michael Snyder of Stanford puts it, "There are some really dramatic changes ... no matter what class of molecules you look at."

The researchers followed 108 volunteers for periods of one to seven years. Every few months the participants provided a suite of samples: of blood and stool, plus skin, oral, and nasal swabs. Using that material, researchers evaluated 135,000 molecules and microbes. "The analysis revealed consistent nonlinear patterns in molecular markers of aging, with substantial dysregulation occurring at two major periods occurring at approximately 44 years and 60 years of chronological age," per the study.

The shift at 44 saw changes in molecules associated with cardiovascular disease and the ability to metabolize caffeine, alcohol, and lipids, which NBC News reports are fatty substances (think LDL, HDL and triglycerides) that can be harmful if they accumulate in the blood. The metabolic changes didn't sync with a slowdown in calorie burn in one's mid-40s, NBC News adds, but did reflect the fact that the body is breaking down food differently—what that means is unclear.

story continues below

The shift at 60 concerned molecules involved in immune regulation, carbohydrate metabolism, and kidney function. Molecules tied to skin and muscle aging changed at both times. The earlier aging burst was originally thought to be a false finding skewed by perimenopausal changes in female subjects, but the data found men experienced similar shifts at the same time. The Guardian notes earlier research flagged the potential of a third burst at 78, but the participants in this study were capped at age 75, so that possibility was not explored. (More study stories.)