Why cells age
DNA damage
Errors build up over a lifetime
Shorter telomeres
Chromosome tips shorten as cells divide
Senescent cells
Worn-out cells that stop dividing but linger
Fewer stem cells
Less ability to repair tissue
Lifespan facts
122years: the oldest verified person
~79years: U.S. life expectancy
~47years: U.S. life expectancy in 1900
100,000+Americans aged 100 or older
Much of the rise came from clean water, vaccines, antibiotics and safer childbirth.
What helps
Strong evidence
- Regular physical activity
- Not smoking
- Good sleep and social ties
Still being studied
- Drugs that clear senescent cells
- Gene and stem-cell therapies
- Calorie restriction in humans
Sources: National Institute on Aging; CDC; Guinness World Records
Remember
Aging is complex biology, but everyday habits still have the best proven effect on healthy years.
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Answer key
- What are telomeres?Protective tips on chromosomesThey shorten as cells divide.
- What was the age of the oldest verified person?122Jeanne Calment of France lived to 122.
- About what was U.S. life expectancy in 1900?About 47It was under 50.
- What are senescent cells?Worn-out cells that stop dividingThey stop dividing but linger and can cause harm.
- Which has strong evidence for healthier aging?Regular physical activityExercise is among the best-supported habits.