A doctor said his biological age is 20 years younger than his actual age. Here's his morning routine.

• Longevity expert Dr. Mark Hyman said his biological age is decades younger than his chronological age.
• At 63, he said he's as healthy as 43-year-old thanks to simple habits like exercise and good nutrition.

Dr. Mark Hyman doesn't act his age — the 63-year old longevity expert said his "biological age" (based on markers of cellular health) is 43, thanks to years of honing his personal routine.

There's good evidence that your lifestyle can reduce markers of cellular aging, although tests to determine biological age can be controversial (and Insider hasn't independently verified Hyman's cellular health markers).

And you don't have to take drastic, expensive measures (like infusions of teenager blood) to stave off age-related decline.

Habits like diet, exercise, sleep, supplements and stress management may be able to add healthy years to your life, helping you feel (and potentially even look) younger, although the science around some anti-aging strategies is mixed.

Hyman isn't against aging — he just wants us all to do it better. He said it's a common misconception that getting old automatically comes with health problems like achy joints, foggy thinking, and chronic illness.

"People don't realize those problems occur with things that we can change, that are reversible. It's a treatable condition, as opposed to an inevitable decline," Hyman told Insider.

His new book "Young Forever" breaks down the science of healthy aging, with tips for habits to extend not just your lifespan but your "health span."

He said longevity strategies like good nutrition and exercise are key for not just a long life, but a better quality of life, and his healthy routine helps stave off longer-term problems while keeping him in peak shape right now.

"Something to make things better decades down the road is kind of a hard sell. You're not just adding years to your life, you're adding life to your years," Hyman said.

He starts the day with meditation, coffee, and time to write

Hyman said the first thing he does every morning, after waking up at 6 am, is meditate for 20 minutes.

Then, he enjoys his morning coffee, and sits down for some dedicated writing time.

Evidence suggests both habits can aid longevity. Coffee linked to lower risk of conditions like heart disease and dementia. and provides a wealth of health-promoting plant-based compounds called antioxidants. Meditation can help improve mental health and reduce stress, a major factor in how quickly we age.

Strength training exercise is an essential part of the healthy aging routine

After his coffee, Hyman hits a strength training routine with resistance bands, which he said has helped him build muscle and reduce back pain.

"It used to be doing yoga, tennis, or walking. Resistance training really transformed my body and health," he said.

Research suggests that even small amounts of strength training can reduce health risks. While lifting weights is a great form of strength training, resistance bands can offer a convenient, portable option if you're traveling or don't have access to a gym.

Hyman said his morning workout is about 30 minutes, but if possible, he likes toget moving throughout the day with activities like hiking or biking.

"My happy place is about three hours of exercise a day," he said.

After his morning workout, Hyman uses a steam shower and cold plunge, staying in the 40-degree water for three minutes. Some evidence suggests hot and cold exposure may reduce inflammation and improve metabolism.

His healthy aging breakfast is high-protein and packed with nutrients

Following his morning workout, Hyman fuels up with what he calls a "healthy aging shake," with a combination of plant nutrients and healthy fats from ingredients like berries, chia seeds, and hemp seeds.

He also has 48 grams of protein, an essential nutrient for building and maintaining muscle, which he gets by adding whey protein powder to his shake.

"As you get older, muscle mass is more important. It's a critical piece of healthy aging," Hyman said.

He follows a "pegan" diet, a combination of paleo and vegan which focuses on mostly plant-based whole foods, he previously told Insider.

Hyman said his supplement routine includes creatine, for muscle and brain health. He also takes a special type of recently-discovered fatty acid called C15:0, linked to better sleep, more energy, and lower stress.

For people who don't yet have a longevity routine, old-fashioned healthy habits like exercise and dietary changes can be one of the simplest changes to make for better health,

"The most important things are exercise, and a diet with healthy fats and plant foods," Hyman said. "No amount of supplements can replace those."