"60 is the New 40" is more than a marketing slogan. The phrase is also a metaphor for optimism, as well as a metaphor for good health.
How can 60 really be the new 40? First, there are the demographics. Forty years ago, when today's 40-year-olds were just being born, 40 was a fairly substantial age. In the early 1970s, every 40-year-old had lived through World War II. For the Americans, many of the men fought in the Korean War and some may even have fought in the Vietnam War. In the early 1970s, most women had had their first child by age 25. Today, child-rearing years for adults frequently begin in their 30s and even late into their 40s. Life expectancy in 1970 was approximately to age 71. Today, average life expectancy is to age 79 or 80. Putting everything together, it can reasonably be stated that our "senior years" keep getting pushed further and further back.
"60 is the new 40" means there is plenty of productive life ahead. The phrase implies that, if one is ready, able, and motivated, whole new aspects of living can be explored. Whereas in 1970, 40-year-olds were often beginning to be established in middle-management roles in their white-collar companies, or were becoming shop stewards and supervisors in their factories, today men and women in their 60s are becoming entrepreneurs and launching their own businesses. Backed by a lifetime of experience, people in their 60s are going back to school to get the undergraduate or graduate degree of their dreams, or they're setting up shop for themselves as artists, artisans, or consultants. Regardless of the particular individual choice, the point is that people in their 60s are manifesting the spirit and vision that was previously thought to be the special province of those much younger, specifically, men and women in their 20s and 30s. But it would be a stretch to say that "60 is the new 30", so we'll stick with "60 is the new 40".
But these new activities and endeavors require physical resources and energy.1 If one is not healthy, 60 may in fact not be the new 40. If one is not enjoying good health, then one's focus is usually primarily directed toward getting well. For 60 to really be the new 40, that is, for one to be fully engaged with family, friends, and work, for one to be focusing on the present and maintaining a positive, expectant attitude toward the future, an optimum state of health is required. Such an optimum varies from person to person. What is needed is for us to be functioning at our optimum. Such maximal functioning is based upon numerous factors, including a healthy, nutritious diet,2,3 regular vigorous exercise, and consistent, sufficient rest. Putting these lifestyle choices into place and making these elements of healthy living habitual will go far toward helping all of us make our chronological age irrelevant.