Debra Whitman is an economist and expert on aging issues. As AARPs chief public policy officer, she leads global policy and research to help communities, lawmakers, and the private sector make aging easier. She has also served as staff director for the Senate Special Committee on Aging and as a researcher in the Social Security Administration.Below, Whitman shares five key insights from her new book,The Second Fifty: Answers to the 7 Big Questions of Midlife and Beyond.Listen to the audio versionread by Whitman herselfin the Next Big Idea App.1. Zip codes determine how long we live.On average, Americans live only 76 years. Our lives are shorter and less healthy than those of people in our peer nations and people in many poorer nations. However,wherewe reside in this country dramatically affects our lifespans. Between the longest-lived county, Summit in Colorado, and the shortest, Oglala Lakota County in South Dakota, there is a 20-year difference in average lifespan. And residents of West Virginia tend to develop chronic health conditions two decades earlier than those in Wisconsin.These disparities are linked to the social drivers of healththings like education, income, access to affordable health care, and zip code. Social drivers account for 60 percent of our longevity. The rest is split about equally between genes and the healthcare we receive.Not surprisingly, higher incomes equate with longer life: men in the top one percent of wealth outlive men in the bottom one percent by 15 years. There are disparities by race, too: Asian Americans live nearly 20 years longer than Native Americans.Certain state policies help drive health and longevity. These include the more obvious laws, like higher tobacco taxes, which reduce smoking, but also those related to minimum wage and paid family leave. We need to use this countrys abundant resources to create environments that support all of us in living healthier and longer.2. Health isnt just what we eat and how many steps we take.We can all take action to improve our health and extend our lives. Youve probably heard about the five healthy habits: a good diet, exercise, a healthy body weight, no smoking, and little or no alcohol. People who practice four of the five habits gain eight to ten years free of major medical problems such as cancer and heart disease.But mindset has a big impact. Harvard epidemiologist Becca Levy found that people with the most positive perceptions of aging live more than seven years longer than their peers with the most negative attitudes. The positive thinkers have fewer strokes and heart attacks, higher physical functioning, and shorter recovery times after illness or injury.The other big health enhancer in aging is relationships. Healthy relationships are linked to better immune functioning, lower blood pressure, and lower levels of inflammationall critical to good health. By contrast, prolonged isolation has roughly the same impact as smoking 15 cigarettes a day. Researchers from the Harvard Study of Adult Development found that the best predictor of physical and mental health for people in their eighties was not cholesterol level or blood pressure but having had good relationships in their fifties.3. Cognitive change is normal as we age, but cognitive decline is not inevitable.Americans tend to overestimate the likelihood of dementia. About half of us believe we will probably get it when only about 15% of people between 75 and 79 have even mild cognitive impairment. And our chances of getting dementia have declined over the last decade, likely because of improvements in nutrition, health care, education, and lifestyle.The Lancetrecently identified 12 modifiable risk factors that account for about 40 percent of dementia worldwide. Some of thesesuch as air pollution and inadequate educationneed to be addressed by the government and the private sector. But many relate to individual behavior.Adopting the five healthy habits I mentioned earlier could help lower dementia risk with aging by up to one-third. Sleep is important, too. People who sleep seven to eight hours a night are significantly less likely to develop dementia than those who sleep five to six hours. Nurturing relationships and staying socially active lower the risk, as does strengthening the muscle of our brain with activities that involve memory, attention, and reasoning.Some cognitive faculties improve as we age: our grasp of meaning and the connections between ideas and our ability to think constructively. We tend to become more emotionally resilient. Our brains continue to change in our second fifty, but not all of that change is decline.4. Older workers are a boon to the economy.When I was a kid, the norm for many Americans was education, followed by a few decades of work, followed by retirement. The reality today is different. More older Americans are working than ever before, even as we see our skills become outdated with no opportunities for reskilling. The average age of retirement continues to creep up. Working while retired is the new norm, and many Americans will never be able to retire.Helping older people stay in the workforce benefits individuals, employers, and the economy. Among older workers, it slows cognitive decline and keeps people socially engaged. Employers with multigenerational workforces see more innovation and higher productivity in both younger and older workers. And older workers help grow the economy. Research has shown that age discrimination that pushed older Americans out of the workforce cost $850 billion for one year in lost wages, salaries, taxes, and consumer spending.But not everyone can keep working indefinitely, and we must better support those who cant. For people who want or need to keep working, we must address the barriers they face, such as outdated skills, caregiver demands, and ageism. About half of Americans are laid off or pushed out of jobs at least once after turning fifty. In the changing work landscape, we allworkers, employers, and lawmakersneed to reimagine what it means to earn and learn over a lifetime.5. We canand mustmake it easier to age well in America.The programs that support us as we age desperately need updating. Social Security hasnt been touched in 40 years, and our safety net programs remain stingy compared to those of our peer countries. The cost of long-term care in the United States can bankrupt people.We need a comprehensive Plan for Aging Well in America that tackles these challenges. This plan should address the disparities that cut the lives of some Americans short while others live comfortably into their nineties. It must ensure affordable long-term care for older people who are ill or disabled, while helping all of us stay as healthy as possible for as long as possible.Too often, we operate from a scarcity mindsetthe belief that supporting longer, healthier lives for older Americans will drain the resources needed for young people or that supporting young people is not connected to health in later life. But investing in our youngest citizens makes them more likely to be healthy adults. Creating a better society for older people lays a foundation for future generations.Improving health care, income, employment, and long-term services costs money. But the less we invest now, the more we will spend later to care for people as they age. And the benefits of such investments arent only economic. A healthier and more financially secure second fifty means less physical suffering and psychological stress, and more freedom to enjoy those final years.This article originally appeared in Next Big Idea Club magazine and is reprinted with permission.