Drastic signs of ageing show up twice in a lifetime. Once around 44, and then at...

Often we look into the mirror and wonder, what happened? When did we start to look so old? The blemishes and wrinkles that weren't there until a few weeks back have now made a permanent place on your face. While it might look like life is catching up, science has an explanation.

As per a study, there are two specific ages when humans see a drastic change in their appearance. The first is around the age of 44, and the second is when you turn 60. 

The study on molecular changes associated with ageing was published a few weeks back and states that the changes are not gradual, but really drastic and noticeable.

"We're not just changing gradually over time; there are some really dramatic changes," geneticist Michael Snyder of Stanford University said.

"It turns out the mid-40s is a time of dramatic change, as is the early 60s. And that's true no matter what class of molecules you look at."

As we age, the risk of contracting diseases also increases. Snyder and his team have been working to understand the biology of ageing to help avoid and treat these conditions early on. 

Also Read: Bryan Johnson’s latest anti-ageing experiment goes awry

The researchers tracked a group of 108 adults who donated biological samples every few months over several years. An average of 47 samples were submitted by each participant over 626 days. The longest-serving participant gave 367 samples.

In these samples, they tracked different kinds of molecules, such as RNA, proteins, lipids, gut, skin, nasal, and oral microbiome taxa, for a total of 135,239 biological features.

Clear signs of ageing twice

The team found that at two stages of a human being's life, there was a clear change in the abundance of different kinds of molecules in the body. These changes were noticed in around 81 per cent of all the molecules studied in either one or both of these stages. They peaked in the mid-40s, and again in the early 60s.

During the mid-40s, changes were seen in the metabolism of lipids, caffeine, and alcohol, as well as cardiovascular disease, and dysfunctions in skin and muscle. During the 60s, it was about carbohydrate and caffeine metabolism, cardiovascular disease, skin and muscle, immune regulation, and kidney function.

In women, menopause or perimenopause were not found to be a factor. "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," metabolomics and first author Xiaotao Shen, of Nanyang Technological University Singapore, said.