Have you ever stood in front of the mirror one morning and instantly thought you'd aged a whole night in one! Well, you may not be dreaming! Researchers have found that growing old doesn't occur as a gradual, slow process. Rather, our bodies experience two dramatic changes—one at the age of 44 and one at 60.

Researchers headed by geneticist Michael Snyder at Stanford University explored how human bodies transform as we age. They discovered that yes, we do undergo gradual aging, but there are two such major points in life when our bodies undergo major transformations.

"We're not just changing gradually over time; there are some really dramatic changes," explained Snyder when the study was published in August 2024.

These sudden shifts occur regardless of which section of the body you examine—our blood, skin, or even the little microbes that live inside us!

Scientists followed 108 adults over a few years to study these patterns of aging. Volunteers gave biological samples—such as blood and saliva—every few months so researchers could examine how their bodies were changing.

They tested more than 135,000 various biological markers within the body, ranging from proteins and lipids to gut flora. In total, they gathered an astonishing 246 billion data points!

When they processed the data, two distinct peaks emerged:

  • The first major shift occurs in the mid-40s (age 44).
  • The second shift occurs in the early 60s (age 60).

What does the body experience at these ages?

Scientists observed that at about age 44, most of the biological changes take place, such as:

  • How the body metabolizes fats (lipids), caffeine, and alcohol.
  • Increased risk of heart disease and muscle weakness.
  • Skin begins to change and exhibit signs of aging.

Then, at age 60, another significant change takes place

  • How our body metabolizes sugar (carbohydrates) is altered.
  • The immune system, kidney function, and heart health undergo dramatic changes.
  • The body's capacity to repair itself decelerates.

As the first big change occurs around the age when many women experience menopause, scientists were curious to find out if that was why. But they discovered that men experience the same changes at the same age 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 Xiaotao Shen, the study’s lead author.

This research examined a small sample of individuals between 25 and 70, so scientists wish to research a greater number of more varied individuals in order to see better why these unexpected aging changes occur.

By knowing more about when and how the body adapts, researchers hope to develop more effective means to retard aging and prevent such conditions as heart disease and Alzheimer's.

(This article is based on the study published in Nature Aging)

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