A 101-year-old former doctor who worked until he was 85 shared his 3 longevity secrets — including eating sardines

• 101-year-old William is active and lives independently.
• He shared what he thinks are some of his secrets to becoming a centenarian.
• They include a varied career, lifting weights, and eating sardines.

A 101-year-old man who worked until he was 85 shared his secrets for living a long, healthy life.

Born in 1922 in the UK, William (who didn't share his last name) is older than Mount Sinai Hospital in Toronto, where he's a patient. There, doctors from the geriatrics department treat any healthcare issues that come up and provide support to help him stay healthy and live independently at home.

William is one of a small, but growing, group: centenarians. In 2024, 0.03% of the US population was 100 years old or over. But the Pew Research Center, using data from the US Census Bureau, estimates this will grow to 0.1% by 2054.

Dr. Samir Sinha, William's doctor at Mount Sinai Hospital, told Business Insider that he hopes to live as long as William and mirror his optimism and curiosity.

Although a team of doctors helps William stay healthy, lifestyle factors can also play a huge role a person living past 100. (Their genetics likely helps, too.)

Sinai Health, the parent company of the Mount Sinai Hospital, shared what William thinks has helped him live so long.

Keeping active

William would swim four or five times a week when he was younger. Now, he walks and lifts 15-pound weights daily.

"Beware of inactivity," he said. "I don't allow myself to become immobile."

Dr. Sinha said that the mix of resistance and aerobic exercise that William does every day is "ideal" to "maintain his vascular and brain health as well as to keep his muscles and bones strong."

Research suggests that just 20 minutes of walking a day or 30 minutes of exercise that strengthens muscles a week could help you live longer.

Eating home-cooked meals — and lots of sardines

William said that he still prepares all his meals. Home cooking can make it easier to eat fewer ultra-processed foods , which were linked to a higher risk of 32 health issues , including type 2 diabetes, cancer, and cardiovascular disease in a study published in The BMJ earlier this year.

William has also always eaten sardines, starting at the age of six, "before they discovered omega 3s ," he said.

Sardines contain lots of nutrients necessary for our bodies to function, such as potassium, iron, and calcium, and were linked to better cardiovascular health and lowered blood pressure in a 2023 study published in Frontiers in Nutrition.

Having a long and varied career

William has had various jobs and didn't retire until he was 85.

He started as a primary care physician, then moved into public health and workers' compensation, and was a psychotherapist by the time he retired.

"Change in careers is good for anybody," he said, adding, "You can't sleep through life. You have to stay interested."

Dr. Sinha said that a long and varied career allowed William to stay engaged and maintain a purpose, but it is also beneficial to volunteer, have hobbies, and social stimulation.

Healthy aging expert Dr. Heidi Tissenbaum, a professor in molecular, cell, and cancer biology at the University of Massachusetts Medical School, previously told BI that keeping your mind busy is a basic tenet of longevity .