I'm the 83-year-old founder and chairman of a PE firm. Here's my daily routine that's reversing my biological age.

This as-told-to essay is based on a conversation with Robert Rosenkranz, the 83-year-old chairman of Delphi Capital Management, about his daily routine. It's been edited for length and clarity.

I started my career as an economist and tax lawyer before founding my private equity firm, Delphi Capital Management. From 1987 to 2018, I was the CEO, managing over $40 billion in assets.

At 83, I find it hard to retire successfully. Part of what made me successful in my career is that I enjoyed the process. And if you enjoy the process, why stop?

When I stepped back from day-to-day management at Delphi in 2018 at 75, I knew staying engaged with different projects would be more satisfying than hanging out on a beach or playing golf. I'm still the company's chairman and provide counsel to the senior management team.

I know a lot of people who retire and, over time, become less interesting and less healthy. A good friend of mine, Byron Wien, used to say, "If you work forever, you'll live forever." It didn't work out for him, but I'm going with it.

Here's what a typical day looks like.

I wake up at 7:30 a.m. every day

I usually skip breakfast and start my day with a cup of coffee. I practice intermittent fasting and consume all my calories between 1 p.m. and 9 p.m.

I've been working with top longevity scientists as part of my philanthropic work in life extension research. Their studies show that caloric restriction and regular exercise can reverse biological aging. I've been at this for about four years, and I'm biologically six years younger than when I started.

I've also experienced dramatic improvements in my long-term memory. I realized I can recall books I've read or conversations I've had from over 40 years ago. Fasting matters, but so do exercise, sleep, and the mindset. It's the whole routine working together.

Exercise is a part of my non-negotiable morning routine

I exercise two or three times a week. I do weight training and cardio, or play tennis with a professional.

I watch a TV series while I train. I'm hooked on the show Slow Horses.

I spend my mornings with newspapers and AI

I read the Financial Times, The Wall Street Journal, and The New York Times newspapers daily with my coffee. These have been my primary sources of information throughout my career.

I'm a techno-optimist. My instinct is to be an early adopter of technological advances so they can serve me well in my activities. I'm a heavy user of Claude and ChatGPT. It's almost like having a couple of PhDs at my disposal 24 hours a day.

My workspace reflects both philosophy and profit

My office tells the story of my career. On the wall opposite my desk is a magnificent image of the Chicago Board of Trade by Andreas Gursky. It reminds me of some of the silver trades I made early in my career that helped me build my reputation.

I also have a 1930s Paul Strand image of people walking past a building on Wall Street. It shows people looking completely overwhelmed by the architecture of the buildings they're passing. That symbolized Strand's thinking about the overwhelming nature of capitalism and finance in those days.

There's also an early image of the Buddha from Gandhara, along with several other images from Buddhist iconography.

I schedule every hour, including social calls

My typical day includes three to four hours of scheduled calls or meetings. Even my social calls are scheduled.

I'm very conscious about my social relationships. I think about which social relationships serve a purpose, which ones I want to nurture, and which need repair. Some of my most important friendships go back decades, including those with Mike Milken, Paul Singer, and Kiril Sokoloff. Relationships like those require the same intentionality I bring to everything else.

I don't take unnecessary meetings, and I'm quick to say no to demands on my time that don't align with my priorities. One of my guiding principles is to do less, but with greater intensity. By doing less, I mean eliminating non-essentials from your life.

My Delphi work is now just 2-3 hours a week

I work in a non-executive capacity at Delphi. I provide my input at weekly investment committee meetings and have regular calls with senior management.

COVID-19 taught me I don't need to be physically tied to any particular location. I own homes in Aspen and London, and I spend time in East Hampton and New York as well. I can function just as well from any of them.

I break my fast at 1 p.m. with a salad

I break my fast with a salad and some protein. When I have business meetings, I prefer lunch in the office, and we usually order takeout from a nearby restaurant.

If there's a special occasion, I might have my cook prepare a nice meal.

Stoicism helped me build my firm

Since the early days of my career, I've relied on Stoic principles to guide my decision-making. The principles of Stoicism have helped me rein in toxic emotions like anger and fear, so I can respond to events calmly and rationally.

There have been instances when people have behaved in ways that made me very angry. Stoic philosophy taught me that by taking a time-out, not reacting emotionally, and thinking more rationally about the situation, I can achieve better outcomes.

These days, my primary job is reading and absorbing information about what's happening in the world. I can't separate investment time from everything else. Almost everything I do has investment implications.

If I read headlines about fiscal policy or new legislation, my mind immediately jumps to inflation, interest rates, and market positioning implications. If your mind is active, everything you do will start to interconnect with each other.

I also spend a lot of time working on various philanthropic projects. I'm actively involved in many activities in the public policy, arts, and medical science fields.

I have dinner at 8 p.m. and read afterward

I eat dinner at 8 p.m. My wife, Alexandra, and I have a personal chef in New York and in Aspen, so we usually have very nice dinners.

After dinner, I sit down and read a book. My reading is eclectic and driven by my interests in art, science, and public policy.

I go to bed around midnight

I get about seven and a half hours of sleep every night. Sleep becomes even more critical for health and longevity as you get older.

Weekends are for family and physical activity

I usually won't schedule business activities on weekends. Instead, I play tennis, bike, and socialize with friends.

One of the hardest things to schedule is time with my children and grandkids. My grandkids are in different schools around the country, my kids have busy schedules, while I spend most of my time in Aspen.

We usually get together in the Hamptons and hang out as a family. Family time requires the most planning, but it's worth it.