How to Live to 100

The latest research suggests the key to longevity lies in changing daily habits.

Live to 100 ebook
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Kuhns earns extra cash from the gig, too. "[My wife and I] have more available funds when I'm working than during the months when I'm not," he says, and this year he got promoted to a higher pay grade.

Doreen Orion, 52, and her husband, Tim Justice, 54, decided to scale back work and hit the road in their 340 square-foot RV, so they could focus on adventure, each other, and reducing their dependence on material goods. She documented their trip in her 2008 memoir, Queen of the Road. As psychiatrists who work for insurance companies, they can do much of their work remotely. "We had a really good marriage before, but being thrust into new situations all the time and having to problem-solve, it can't help but bring you closer together," she says. Orion and her husband recently decided to put their Colorado home on the market and live in their RV full-time.

While still in her twenties, Nicole Mladic, a communications director in Chicago, realized she was never going to save enough for retirement if she continued on her current trajectory of little or no savings each month. So she started slowly by saving 2 percent of her salary each month. A few months later, she raised it to 3 percent, then 4 percent, and eventually reached her goal of 10 percent. Today, Mladic is in her early thirties and her net worth is over $100,000. "The thought of saving 10 percent of my salary for retirement each month seemed impossible when I first started working," says Mladic. "But by starting small, it was easy to get to 10 percent, and far less of a shock to my budget."

George Vaillant, a professor of psychiatry at Harvard Medical School, has overseen the longest-running longitudinal study of health and happiness. His study has tracked the lives of more than 500 Harvard students and men from inner-city Boston since the 1930s, and has drawn some intriguing conclusions, including that stable relationships are one key to a long and happy life. Divorce, he says, "is very bad for your health."

Vaillant says what makes him happiest now, at age 77, are his grandchildren. His advice is sometimes at odds with what one usually hears: He urges people to take money out of their retirement accounts to go on vacation, because learning how to relax and spend time with loved ones is essential to one's happiness later in life. "Just remember, if you get nothing else out of talking to me, to put some of your IRA money into vacations," he says.

As for what brings happiness to that retirement, he says it almost always comes down to relationships. "There were three things that correlated with a fun retirement: 1) whether your marriage was good, 2) whether you took fun vacations before you retired, and 3) whether you have always liked doing things for other people. So it's being more interested in others than yourself that leads to a happy retirement, and having somebody you enjoy being with. And it's having learned before you retire how to play." That's why he suggests investing in vacations long before retirement—to practice.

Love of grandchildren, he found, can trump even disease. "People in poor health with 13 grandchildren are happy … I'm 77, and what I enjoy most are my grandchildren."

The chapters that follow are designed to help you sort through the seemingly endless findings about what you can do now to increase your odds of being a healthy and happy 77-year-old, 90-year-old, and beyond. Getting your heart rate up by exercising at least 150 minutes a week, for example, can cut your chances of heart disease and cancer. Eating a Mediterranean diet, which is heavy on olive oil and fish, capping red meat at 18 ounces per week, flossing daily, sleeping at least six hours a night, and having no more than two drinks a day for men and one for women also appear to promote good health.

To boost your chances of happiness, build a long and loving marriage, cultivate gratitude and optimism, and commit to constant self-improvement. To afford your long life, start a vigorous savings plan as early as your twenties, make frugal lifestyle choices, such as living in a smaller home and cooking more meals at home, and work as long as possible, well past age 65.