What If You Stopped Aging at 25?

What If You Stopped Aging at 25? On your twenty-fifth birthday, you blow out the candles, and your body stops aging. Forever. No wrinkles, no gray hair, no back pain. You get carded at sixty. You beat your marathon time at fifty-five. But you stopped. And nobody else did. Your mom gets older. Your best friend Leo goes gray. And one day, you're the only one left who looks like the photos. Would you want to stop aging at 25? Tell us in the comments. 0:00 Leo's eightieth birthday 0:15 What if you stopped aging at 25? 0:18 The day the clock stopped 1:05 Forever twenty-five 2:26 Why do we age? 3:53 Nature's rule-breakers 4:33 What could go wrong? 5:28 Mom 6:04 Left behind 6:41 The bench 7:10 The one who remembers 8:25 The ending Science notes: the "what if" is fiction, but the science is real. This video is not medical advice. The human body has roughly 30 trillion human cells (Sender, Fuchs and Milo, PLOS Biology, 2016), and replaces about 330 billion of them every day, around one percent (Sender and Milo, Nature Medicine, 2021). Aging is thought to come from many kinds of damage adding up over time (Lopez-Otin et al., "The Hallmarks of Aging", Cell, 2013 and 2023), including everyday DNA damage that cells repair only imperfectly. In the early 1960s, Leonard Hayflick and Paul Moorhead found that normal human cells grown in a dish divide only a limited number of times, about 40 to 60, before they stop (the "Hayflick limit"). Telomeres, the protective caps at the ends of chromosomes, get shorter as cells divide; the 2009 Nobel Prize in Physiology or Medicine went to Elizabeth Blackburn, Carol Greider and Jack Szostak for discovering how telomeres and the enzyme telomerase protect chromosomes. Skin makes less collagen as we get older, which is one reason it wrinkles. After about age 30, people lose roughly 3 to 8 percent of their muscle mass per decade if they don't train (Volpi et al., 2004). Many adults gradually lose the ability to hear very high-pitched sounds (around 17,000 hertz and up) as they age. The oldest person whose age has been fully verified is Jeanne Calment of France, who died in 1997 at 122 years and 164 days. Turritopsis dohrnii, often called the "immortal jellyfish", is only about 4 to 5 millimeters across. When it is injured or stressed, it can turn its adult body back into an early polyp stage and start its life cycle again (Piraino et al., Biological Bulletin, 1996). In the wild, most still die from predators or disease. Naked mole-rats are mouse-sized rodents that can live more than 30 years in captivity, while house mice usually live about 2 to 3 years. A 2018 study of thousands of records found that their risk of dying did not rise with age the way it does in other mammals (Ruby, Smith and Buffenstein, eLife, 2018). #whatif #aging #science #animation