A 91-year-old interior designer still plays golf. She shared her three secrets to longevity.

• Sari Mainzer is 91 years old and still plays golf regularly.
• Exercising regularly could be one lifestyle factor that has helped her stay healthy.
• She also tries to step out of her comfort zone and keep busy, she told Business Insider.

The year was 1990 and Sari Mainzer was looking for something to do at a hotel in Maine. The hotel was on a golf course, so she decided to grab a club and give it a try, sparking a 34-year-long hobby that she still does at the age of 91.

Mainzer added golf to the list of all the ways she kept active. On top of her work as an interior designer, she played volleyball in high school, fenced in college, and played tennis into her 80s .

While longevity is partly due to genes and luck , Mainzer's lifestyle has likely contributed to her staying healthy and active in later life.

Research suggests regular exercise is hugely important for longevity , with a study published earlier this year in BMJ Evidence-Based Medicine finding that a healthy lifestyle could offset the effects of a genetic predisposition to a shorter lifespan by 62%.

Mainzer shared her secrets to staying active into her 90s with Business Insider.

Stay physically and mentally active

Mainzer believes "activity, activity, activity," whether physical or mental, has helped her stay young.

In addition to golfing, Mainzer keeps herself busy by working on a select few interior design projects with her daughter, who has taken over her business. She has also started a program at her Atria Senior Living community in Roslyn Harbor, New York, to help incoming residents decide which items to bring and how to maximize the space in their apartments.

A 2019 study published in JAMA Neurology found that people with higher cognitive reserve — meaning they are able to think efficiently and flexibly, and have minimal signs of brain aging — had a lower risk of developing dementia.

Step out of your comfort zone

"Don't be afraid to try new things," Mainzer said. "Don't be afraid to fail. It's not going to come knocking at your door, you have to go after it."

Since moving into her senior living community, Mainzer has tried a variety of new things. She paints every Saturday and plays bridge three times a week.

Learning new things creates new connections in our brains, which helps keep them active, Heidi Tissenbaum, a molecular, cell, and cancer biology professor at the University of Massachusetts, previously told BI. This is thought to be key for healthy aging.

Meet new people

Mainzer doesn't just play golf for the exercise, she also likes how it helps her meet new people.

When trying new things and finding yourself in new situations, she said, "don't be afraid to feel alone" because meeting new people can "broaden your horizons."

Professor Rose Anne Kenny, a gerontologist at Trinity College Dublin, previously said that positive social relationships are just as important for longevity as more obvious factors such as a healthy diet or regular exercise.