At 103 years old, I’m the ‘world’s oldest doctor’: My 3 rules for a long, happy life are so simple—I tell it to ‘all my patients’

Howard Tucker died on Dec. 22, 2025 at age 103, shortly after writing this essay for CNBC Make It. It is published here with his family’s permission.

I spent more than 75 years practicing as a neurologist, continuing until my hospital closed in 2022. Now, at 103 — and recently named the oldest doctor ever by Guinness World Records — people often ask how I stay happy, sharp and fulfilled.

I don’t believe there is one magic answer. Good genes and good luck certainly can give you a head start. But over the years, I’ve come to believe there are a few principles that matter a great deal.

These are my three non-negotiables for a long and meaningful life — they are simple, and pretty much anyone can follow them.

I tell all my patients that the mind is like any other muscle in the body: If you don’t use it, it weakens.

My work keeps me thinking, learning and solving interesting problems. When one chapter of my medical career ended, I found another way to keep going through medical-legal review and learning how to use social media. I’m not looking for an excuse to stop.

In my early 60s, I attended law school at night after working full-time as a physician. I passed the Ohio Bar Exam at 67. I never set out to break a record. I did it because law, like medicine, interests me and I have always believed it is important to keep learning.

Work does not have to mean a job or career. It can mean volunteering, reading, learning a skill, playing music, joining a club or finding any activity that keeps your mind active.

I have seen many people slow down once they stop engaging with the world. In my experience, staying mentally active is one of the best things you can do for yourself.

When people ask me about my longevity, most want to know about a secret diet or exercise. Diet and exercise matter, of course. But I also think your outlook on life matters.

I have been around for a long time. Like everyone else, I experience disappointment, loss and unfairness. But I never think it makes sense to carry the hatred around with me.

Anger and resentment take energy. They take a physical toll. In my view, they do more harm to the person carrying them than to anyone else. Anger can raise your blood pressure, increase stress hormones and increase your risk for heart disease over time. Not to mention the mental energy spent hating someone.

You don’t have to forget every wrong or excuse bad behavior. The point is to not let bitterness take over your life. I have always felt it is healthier to move forward, to stay interested in other people, and to focus your energy on the things that give life meaning.

I don’t believe that living well means denying yourself every pleasure.

I enjoy a martini. I enjoy a good steak. My wife of 68 years, Sue, is a wonderful cook, and we always eat well. We also believe in having balance, plenty of salad, vegetables and moderation in all things.

To me, moderation is what makes enjoyment possible over the long run. Have a sensible approach to what you eat. The same is true in many parts of life. Too much of anything can wear you down. Too little can do the same.

So the best advice I can give is to keep your mind active, let go of bitterness and enjoy life. Each day is a chance to live well, so why not make the most of it?

Dr. Howard Tucker was a neurologist from Cleveland, Ohio. He was named the “Oldest Doctor Ever” by Guinness World Records at age 103. Throughout the pandemic, he taught medical residents and treated patients at St. Vincent Charity Medical Center, as well as law students at Case Western Reserve University. He also starred in the feature documentary, ”What’s Next?″, produced by his grandson, Austin Tucker, and directed and produced by Taylor Taglianetti.

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