That's kind of the premise of the John Scalzi book "Old Man's War". In the book, they take elderly people (aka Wise people), and put their minds/memories into young fit bodies. This, in theory, creates soldiers who are both Wise, and Young/Fit.
John Scalzi is an amazing author. You'll love it. Another good one by him is The Dispatcher. There's even an audiobook of this narrated by Zachary Quinto
Transported are kinda soft sci Fi, and plausible explanation for why a thing can't be done is easily hand waived by technobabble about a device that says it can be.
Are you ever you? You are an amalgamation of experiences that changes from one moment to the next. You aren't the same person now as you were ten years ago, and you won't ever be the same person you are right now ever again.
Huh. A lot of the Keiko/ O'Brien squabble episodes of DS9 are going to be easier to watch, with that idea in place. He's not divorcing or fixing his marriage, because he can simply outlive her and do better next time.
So just filter out neurons and other majorly complicated nervous system cells. Your mind will still age, but your body will not, and that will make you last significantly longer than you otherwise would.
Couple that with advances in alzheimer's/dementia/etc research, the average person could grow to be a century old without breaking a sweat.
Funnily enough in jujutsu kaisen many of the people who got transfigured by patchwork face die of shock because their mind doesn't accept their new body as their. Also I vaguely remember an experiment where surgeons were trying to transplant a entire head. And one of the many issues was the fact that the brain kept waking up and rejecting the body because of small differences like a vain being in the wrong spot. I really need to dig that study up I remember it being a pretty neat and oddly terrifying read.