The 3 ‘Spans’ of Longevity: A New Framework for Living Longer, Better, and More Fully
By Sophia Fay, BS and Sharon Brock, MS, MEd
Today, conversations about longevity often focus on metrics, optimization, and biohacking. We track more, measure more, and optimize more than ever before. While these tools and approaches can help us better understand our personal health data and potentially build healthier habits, they are not sufficient to ensure a life that feels meaningful, connected, and fully lived.
Gerontologist and leadership coach Barbara Waxman offers a provocative perspective on the topic of longevity, inspired by her weekly ritual of reading obituaries. Rather than focusing on how many years a person lived, obituaries capture what mattered most in a person’s life—the love shared, the risks taken, and the legacy they’ve left behind.
This perspective beckons a broader definition of longevity, one that expands beyond lifespan and healthspan (the number of years we are physically healthy), into what Waxman calls the “thirdspan”— the mindset, joy, purpose, and relationships that allow a person to flourish.
“Obituaries are the true highlight reels of our lives. In just a few paragraphs, you see what truly mattered. The passions, the quirks, the loves lost and gained, the impact, the risks taken or not. They’re a masterclass in what it takes to live, not just last,” said Waxman in a TEDx talk.
Lifespan: Adding Years to Life
The first aspect of longevity—lifespan—is the one most of us are already familiar with. Lifespan refers to the total number of years an individual lives and is mostly determined by lifestyle medicine as opposed to genetics.
In fact, some studies show that only 20 percent of how long we live is determined by genetics, while the remaining 80 percent is shaped by our behaviors and choices regarding health, as well as advancements in public health.
“In little over a century, we’ve added three decades to our life expectancy—not from wearables or chasing VO₂ max, rather due to increased access to clean water, vaccines, and antibiotics,” said Waxman.
Healthspan: Adding Life to Years
The overall increase in human lifespan reveals extraordinary achievements of modern society, but it also presents a new challenge as more years lived does not automatically mean better years lived.
This brings us to the second “span” of longevity— healthspan—the number of years we live with minimized disease and preserved physical and cognitive function. Healthspan measures how well we function physically and reflects our ability to remain active, independent, and engaged as we age.
As our understanding of health has evolved, the past decade has seen a surge of interest in self-tracking and health optimization. Around half of adults in the U.S. wear “health wearables” that monitor sleep, activity levels, heart rate variability, resting heart rate, and other health markers in real time. These tools can provide valuable insights into our behaviors and motivate positive health changes, however, Waxman emphasizes that the data these wearables provide should not be the ultimate end goal regarding our health and longevity.
“Understanding health data can be foundational to creating a successful longevity life plan, but it’s important to remember that data is not the destination,” said Waxman. “We’ve become so fixated on data and protocols that we’re losing sight of the significance and the impact of other aspects of our lives that enable us to flourish.”
The Thirdspan: The Flourishing Factor
Waxman offers the compelling idea that another “span” is missing, which she calls the “thirdspan” of longevity. If lifespan reflects how long we live and healthspan reflects how well our bodies function physically, the thirdspan describes how well we flourish, mentally and emotionally, within those years.
The thirdspan encompasses mindset, purpose, relationships, and joy, which are key factors that shape our emotional and psychological wellbeing. Far from being “nice-to-have” qualities, these factors are increasingly being recognized as important contributors, not only to mental health, but also physical health and longevity. For example, multiple large-scale studies have found that poor relationship quality and loneliness are associated with increased mortality risk, placing them alongside factors such as smoking, poor diet, and lack of exercise.
Mindset also plays a significant role. Waxman highlights a study in which hotel housekeepers were told that their daily work, including lifting objects, vacuuming, and making beds, met the Surgeon General’s recommendations for physical activity. After just four weeks, participants experienced measurable improvements in blood pressure and body fat, even though their actual activity level had not changed. Another study on mindset found that individuals who consistently believed they were not active enough had a mortality risk up to 72 percent higher over a 21-year period. These findings suggest that our beliefs about our health behaviors greatly influence our physical health outcomes.
“Research shows the greatest predictor of health later in life isn’t about cholesterol or cold plunges, it’s determined by the quality of our relationships,” said Waxman. “Therefore, starting in midlife, we should put less focus on improving our health data and more focus on cultivating thirdspan qualities, such as mindset, purpose, relationships, and joy.”
Three Steps to Cultivating Thirdspan Qualities
Since the thirdspan is essential for flourishing, how might we cultivate a positive mindset, sense of purpose, quality relationships, and joy in our daily lives?
Waxman offers these three steps:
- Track Joy for 30 days: Along with your protein intake, adopt joy as a data point worth tracking. In a culture that prioritizes productivity and performance, intentionally noticing moments of joy can help shift our mindset in a positive direction and help us experience more joy in our daily lives.
- Improve Two Relationships: Reach out to someone you have lost touch with and let them know why they matter to you. At the same time, consider creating a healthy boundary around a relationship or situation that consistently drains your energy.
- Identify Your “Why”: Write down three reasons why you want to flourish. Perhaps it is to hike a specific mountain, see your grandchild graduate from high school, deepen your friendships, or pursue a passion that brings meaning to your life. Writing these reasons down can serve as a reminder of what truly matters to you.
“These three steps can help define your thirdspan and connect you to the deeper sense of purpose behind your pursuit of longevity,” said Waxman. “Ultimately, the question is not simply how long we live, but how we choose to live the years we are given.”
