A busy doctor says he's reversed his age from 78 to 57. Here's his simple, 3-step workout routine.

A doctor with a packed schedule still manages to fit in exercise to improve his longevity. Here's how.

• Everyone knows exercise is good for you, but many of us don't do enough. 
• Longevity expert Dr. Michael Roizen shared how he fits exercise into his busy schedule.
• He has a walking desk to help him hit 10,000 steps a day, and parks his car one mile from work.

A busy doctor and longevity expert who says he's reversed his age by 20 years shared with Business Insider how he finds time to stay fit.

Dr. Michael Roizen, 78, chief wellness officer at Cleveland Clinic and author of books on longevity, claims his "biological age" (a concept experts are divided on) is 57.6.

Regular exercise is a key part of his health routine. Although he doesn't work out enough to achieve maximum strength or fitness, he said, he walks whenever he can and squeezes in a few dedicated exercises sessions each week.

Research suggests that even small amounts or lower intensity workouts can help keep us healthy.

That may be welcome news to the vast majority of Americans who, according to the National Center for Health Statistics, don't do the minimum 150 minutes of moderate-intensity exercise each week recommended by the government. Evidence suggests a lack of time is one of the biggest factors that stand in people's way.

Here's Roizen's weekly exercise regime.

Cardio three times a week

Three times a week, without fail, Roizen does 48 minutes of cardio, or aerobic, exercise on a treadmill or exercise bike. He chose that number because that's how long he used to play squash for, and he wants to be fit enough to play again.

He does this on Wednesday evenings, Saturdays, and Sundays. If he knows he'll have to miss a session due to a social event, he makes up for it another day.

Cardio exercise has a huge range of health benefits, including reducing the risks of heart disease, high blood pressure, and type 2 diabetes, strengthening the heart, and improving mood, according to the Mayo Clinic.

10,000 steps a day

Roizen walks as much as possible, aiming for 10,000 steps a day. To keep moving throughout the day, he uses a treadmill desk when working in his office, and walks patients in and out of his clinic

He also parks his car a mile away from work, helping him to rack up 2,000 steps in his commute. If he hasn't met his target by the end of the day, he'll get on a treadmill or exercise bike.

The popularly quoted goal of 10,000 steps a day has its origins in marketing for a Japanese pedometer company, but walking has many health benefits. According to a 2022 study published in the journal GeroScience, 30 minutes of brisk walking five days a week appeared to lower the risk of cardiovascular disease and type 2 diabetes, improve mental well-being, and increase longevity.

Even if you can't reach 10,000 steps a day, walking an extra 500 steps a day could improve your longevity, according to a recent study.

Weight lifting twice a week

After two of his three weekly cardio workouts, Roizen lifts weights.

He said that resistance training is great for building muscle and improving longevity.

One 2022 study published in the British Journal of Sports Medicine linked doing between 30 and 60 minutes of resistance training each week with a 17% lower risk of dying from any cause, an 18% reduction in the risk of cardiovascular events, and a 9% lower risk of developing cancer. Similarly, a 2019 meta-analysis published in the European Journal of Preventive Cardiology suggested one or two weekly resistance training sessions could lower a person's risk of dying from any cause.