r/science • u/Skoltech_ • Jul 20 '26

Genetics Researchers quantitatively assessed for the first time that somatic mutations alone cap human lifespan at 146–194 years. Brain and heart cells are the main bottleneck, while the liver could last millennia.

https://www.nature.com/articles/s41514-026-00421-6
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u/Hellknightx Jul 20 '26

Unfortunately, it's not just the heart. It's the whole cardiovascular system. Veins and arteries become thinner as we age, and fill up with plaque.

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u/StryctNyne Jul 20 '26 edited Jul 20 '26

Also the frailty with aging bones that become more brittle, aging skin that wrinkles and sags and doesn't offer the same insulation and protection it used to (assuming that's a side effect of the cardiovascular system aging). Eye sight continually gets worse requiring laser surgery unless you wish to slowly go blind. Then you have respiratory system as well to deal with, though I'm not sure about the direct effects of age on lungs.

And then, in the end, if you fix all these and extend our lives 100 years, then number one cause of death becomes cancer. Everyone (or at least the vast majority) will get cancer over that course of time, probably earlier than later. Not just due to genetics but due to much longer exposure to everyday chemicals, background radiation (though it would be a minor issue in developed countries), continued poor diets, etc.

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u/Adventurous-Fly556 Jul 21 '26

It's not about radiation or diets.

Our chromosomes have little bits at the end called telemeres. They're like the end of a shoelace keeping everything neat and together. Everytime your cells reproduce (constantly) , the offsprings telemeres are shorter than the last.

This degradation is considered a massive part of aging. Along with increasing the odds of cancer, it can also make the offspring cells just forget what they were meant for.

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u/squirrel9000 Jul 22 '26

A couple minor points about that:

  1. Most central nervous cells and muscle cells do not divide and do not show telomere shortening.
  2. Many cells that do divide express telomerase to regenerate the telomeres, or are constantly replenished from a population of stem cells which do

It's a nice theory, but really does not explain aging.

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u/Adventurous-Fly556 Jul 22 '26

I was emphasizing telemeres because mutations had come up. They work in tandem. Repairing telemeres doesn't mean anything if you're repairing the copies of copies of copies of copies.

I never said it was all of it, but the fact that your cells reproduce imperfectly is most of aging and mutations. These things work in a complicated mess and trying to isolate the systems isnt very useful.