Have you ever woken up in the morning and suddenly felt old? There might be a good reason. A series of studies has found that, rather than ageing gradually on a linear timescale, we might have significant "bursts" of getting old during our adult years, said National Geographic.
These usually happen in our mid 40s and early 60s, according to a research team at Stanford University, who tracked thousands of different molecules in people aged 25 to 75. The researchers found that 81% of the molecules didn't change continuously, as you'd expect, but actually transformed significantly around certain ages.
Their "provocative" findings seem to "fly in the face" of current models of ageing, said David Sinclair, a molecular geneticist, longevity researcher and professor at Harvard Medical School.
A separate study by a team in Germany last year found that sudden chemical modifications to DNA occurred in mice in early to mid life and again in mid to late life, and a 2019 analysis found "significant jumps" in concentrations of blood plasma proteins associated with ageing in the fourth, seventh and eighth decades of human life.
This "sudden ageing" can come with "an acceleration in muscle wastage and skin decline", said New Scientist, along with an inability to metabolise alcohol, a swift dwindling of immune cells and substantial increases in the risk of cardiovascular disease and dying.
But with other studies suggesting people often experience a "mid-life crisis" in their late 30s and early 40s, or a "late-life crisis" in their late 50s and early 60s, said Sinclair, it is possible that "associated psychological and lifestyle changes may be responsible for these changes in ageing", and not our "inherent biology".
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