Scientifically Speaking | Researchers find massive ageing shifts twice in life: At 44 and 60

We don’t age at a steady pace throughout life in a straight line. Instead, ageing is more of a roller-coaster with two major waves, as per the new study

During the first few months of isolation during the Covid-19 pandemic, while I was holed up at home, I began to feel more tired. Over the following months, I noticed my hair greyed more than usual. Was it the stress of global upheaval, or was it natural ageing?

Age may simply be a number, but ageing is more than the calculation of how many years a person has lived on this planet.(Unsplash)

There’s no way to know for sure, of course, and outward signs of ageing can be deceptive. However, by examining a wide range of biological markers for ageing, scientists have now reached a remarkable conclusion that fits my observation at the start of the pandemic when I was 44.

We don’t age at a steady pace throughout life in a straight line. Instead, ageing is more of a roller-coaster with two major waves, according to a study led by Michael Snyder from Stanford University. Significant biological shifts occur at specific ages, notably in the mid-40s and around 60 years, the study noted.

Published in the scientific journal, Nature Aging on August 14, the study tracked a whopping 135,000 molecules and microbes in a group of participants aged 25 to 75. Over several years, the participants provided blood and stool samples, as well as swabs from their skin, mouths, and noses. Scientists analysed these biological samples for changes in RNA, proteins, metabolites, and the diverse organisms that populate our bodies. The goal was to get a holistic picture of ageing, rather than focusing on one or a few health indicators.

What the researchers found was striking. The most dramatic shifts in these biological markers clustered around the ages of 44 and 60, suggesting that there are two major periods in life when ageing may accelerate.

The mid-40s spike was particularly interesting because it was observed in both men and women. While the hormonal changes of perimenopause could explain this shift in women, the same pattern was seen in men, leading scientists to believe that broader factors are at play. In people in their 40s, notable changes were observed in molecules associated with alcohol and caffeine metabolism, breaking down fats, heart health, as well as skin and muscle function.

The second wave, around age 60, was marked by changes in the body's regulation of immunity, carbohydrate processing, and kidney function. Skin and muscles also showed signs of ageing, aligning with the increased risk of age-related diseases like Alzheimer’s and cardiovascular disease.

While the study provides important insights into ageing, it’s important to acknowledge its limitations. Although comprehensive in its tests, the study involved only 108 participants, who might not represent the broader population, especially given the diversity of genetic backgrounds, lifestyles, and environmental exposures that influence ageing. Additionally, the participants were aged between 25 and 75, meaning the study did not capture ageing patterns in people younger than 25 or those over 75.

Despite these limitations, the findings are valuable. No experiment can capture all the factors of ageing in every individual. Researchers need to choose between testing many people for a few things or fewer people for many things. In this case, understandably, they chose the latter.

Age may simply be a number, but ageing is more than the calculation of how many years a person has lived on this planet. To understand ageing, we need to look at the concept of biological age. Someone who leads a healthy lifestyle with regular exercise and a balanced diet would probably have a biological age younger than their actual years. On the other hand, chronic stress, heavy drinking or smoking, or illness might make someone older biologically than their chronological age.

In short, reader, your personal ageing experience may vary from the study’s conclusions. However, the broader idea that ageing may occur in peaks is sound.

With this knowledge, what can we do about ageing? Ageing is inevitable and natural, but lifestyle adjustments at critical times can help keep us healthy. Snyder offers sound advice that we would do well to follow: “I’m a big believer that we should try to adjust our lifestyles while we’re still healthy.”

In my case, that means exercising to stay fit and reduce the loss of muscle mass (an inevitable part of ageing) and eating better. The goal is not to prevent ageing or even to extend our lives but to increase "healthspan" – the period of life spent in good health.

Anirban Mahapatra is a scientist and author, most recently of the popular science book, When The Drugs Don’t Work: The Hidden Pandemic That Could End Medicine. The views expressed are personal.