When most people are heading home from work, Dr. Ronald Primus often heads to see patients.
Primus’ office hours typically end by 6 p.m., but as a concierge doctor based in New York City, he makes house calls and sees patients whose “traditional appointments are not possible due to work, travel, or medical circumstances,” so he is essentially available 24 hours a day, he says. “I often go to bed around 1 a.m. or later if my patients need me.”
His work includes a twist. With more than 30 years of medical experience under his belt, the trained internal medicine physician considers himself a long-lived physician. He says he tests patients to assess their genetic health risks and creates personalized health plans for them based on the results. Although he still makes urgent care appointments, his focus dates back to the 1990s on preventive care, trying to help people build healthier daily lives to prevent future chronic diseases and age-related deterioration.
“Back then, no one was using terms like healthy lifespan, biological age, or longevity medicine. We didn’t have wearables, we didn’t have genomics, and yet the principles were already clear: The trajectory to chronic disease often begins years before the first symptoms appear, and maintaining function is as important as treating the disease,” Primus, 66, says.
Now, he points out, “science, tools, and public interest have caught up with the thinking behind longevity medicine.” Physical and mental health are often associated with success, and healthy people generally report feeling more productive at work. The industry has become awash with hot biotech startups, funding from billionaires, expensive longevity memberships to clinics and gyms, and legions of biohacking influencers on YouTube and TikTok.
Primus believes in the power of small habits. “The little tweaks you make every day add up,” he says. And he tries to practice what he preaches. “I can tell my patients what to do until they’re blue in the face. They won’t really pay attention unless I lead by example. I try to check the longevity box as much as I can.”
Here, Primus talks about how she builds a daily health routine, from wearable devices to a diet rich in plant-based foods. Always consult your doctor before making any major changes that may affect your health.
“We try to follow as much as possible the way our ancestors lived before farming.”
CNBC Make It: What do you do every day to stay healthy?
Ronald Primus: I work out seven days a week. I strength train three times a week and also do high intensity interval training. I do Norwegian four-by-four twice a week (a type of interval training aimed at heart health) and twice a week I do 45 minutes of Zone 2 training (a type of exercise that focuses on gradually increasing your heart rate). Weekends focus on stretching and balance training.
I protect my exercise time the same way I protect my important medical appointments. I usually train in the evening after work. I also try to walk for 20 minutes after every meal. This is an easy way to break up sedentary time and can help reduce the rise in blood sugar levels after meals. I try to get up and move at least once an hour while I’m at work, often doing 10 to 20 bodyweight squats.
During an unusually busy week, even if you can’t complete your regular workout, do a short session, walk, mobility work, or a few sets of resistance exercises. In most cases, something is better than nothing.
Optimize your sleep. Bedtime is fixed. I don’t go to bed until about 1 a.m., maybe later, but I wake up around 9 a.m. That means you’re in bed for 8 hours and sleeping about 7+ hours a night. And that’s quality sleep. I try to keep my bedroom completely dark. Make sure it’s cool and below 67 degrees and have a comfortable bed.
CNBC Make It: How do you structure your diet?
Plymouth: I follow as much as possible the way my pre-agricultural ancestors lived. You could call it the paleo diet. I eat only whole foods. No grains, no dairy, no sugar.
I get my fiber and calcium from root vegetables like parsnips, celery root, turnips, and sweet potatoes. I eat a lot of tuna, salmon, and grass-fed meat, but always supplement with vegetables and nuts. I eat fruits like blueberries, raspberries, and blackberries. Eating a variety of whole fruits makes for a great meal.
Our family meals are intentionally simple and built around making sure to rotate protein, vegetables, healthy fats, and a few practical staples. You don’t have to cook elaborate meals or eat expensive fish and meat every night to eat well. The most important pattern is one built around minimally processed foods, including vegetables (fresh or frozen), beans, lentils, eggs, plain yogurt, canned salmon or sardines, frozen berries, nuts, and olive oil when allowed. The goal is not a perfect diet. It’s durable.
I follow a timed breastfeeding period. Eat two meals and a snack within a 6-8 hour window each day, and never stop eating within 4 hours of bedtime. Avoid getting too close to bedtime for the best quality sleep. The longer you eat before bed, the better your health will be and the better your health metrics will be on your Oura Ring and Biostrap (wearable health tracker).
CNBC Make It: What habits have you built specifically for brain health?
Plymouth: No smoking. That’s natural. The vegetable fats in my diet (avocados, walnuts, fish oil tablets, algae oil tablets) help support cell membranes throughout my body, including my brain. The fatty fish in my diet provides DHA (docosahexaenoic acid), an omega-3 fat that is particularly concentrated in the brain and retina.
What really helps the brain is exercise, especially high-intensity interval training. Anything is better than nothing. It increases a hormone in the body called BDNF, which is brain-derived neurotrophic factor, which can stimulate neuron growth and increase neuroplasticity.
The goal is not to create a perfect, super-optimized life. It’s about creating a repeatable routine.
And of course, your brain cleans itself while you sleep, so you get quality sleep. Chronically shortening it affects cognition, mood, metabolism, and long-term health. Sleep is when the brain consolidates memory, rebalances stress and immune signaling, and supports other recovery processes.
To reduce stress, I practice Qigong, a form of meditation, every chance I get. Another thing I do is something called Heart Mass Breathing. When you clip this device to your ear, you can synchronize your breathing with the technology.
Also, I’m very sociable. My wife and I have a lot of friends, we hang out together, we do fun things, and we take a lot of vacations together. I try to make time for my wife, family, friends, and dogs. The goal is not to create a perfect, super-optimized life. It’s about creating a repeatable routine.
CNBC Make It: Given that sociability is important to longevity, what lessons have you learned over the years to make it easier to be sociable?
Plymouth: The main thing I’ve learned over the years is to not sweat the small stuff. When I was younger, I paid attention to what people thought of me, how I was judged, and things like that.
At this point, I’m an adult so I don’t care. But I wish I had learned this when I was younger, and I try to pass that on to my children.
CNBC Make It: We’re coming to the end of our chat, but I can’t leave without asking the questions I always ask longevity experts. What have you been reading lately?
Primus: Even though I practice preventive medicine, I’m still a board-certified internist, so most of the books I read are magazine articles.
I just purchased Michael Fossel’s book “Aging: How we age, ways to reverse it, and prospects for curing the diseases of aging” and Eric Topol’s book “Super Agers: An Evidence-Based Approach to Longevity”. I haven’t reached them yet.
But I’m a nerd. Most of the time, all I do is stay up to date with the medical literature.
Daily health plan of a 66-year-old longevity doctor
Here’s an overview of Plymouth’s daily health routine:
For physical health: Train 7 days a week and maintain consistent sleep habits. For your diet: Stick to whole foods, a diet rich in vegetables, and stick to evening meal time limits. For brain health: Take active steps to protect your brain, such as practicing meditation, eating plenty of plant-based fats, and participating in high-intensity interval training. For social health: Spend time frequently with your wife and friends, take vacations with loved ones. For the media diet: stay up-to-date on medical literature and research.
This interview has been edited and condensed for clarity.
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