In this episode of The Mind–Gut Conversation, Dr. Emeran Mayer speaks with Dr. Jamie Justice, Executive Vice President of the Health Domain at the XPRIZE Foundation and Executive Director of XPRIZE Healthspan, about the science of aging and why living longer has not meant living healthier.

Over the past century, average lifespan in Western countries has grown by about 30 years, yet most people still spend roughly the last 12 of those years in poor health. Dr. Justice explains this gap between lifespan and healthspan, and why research in model organisms suggests that aging itself may be modifiable rather than an inevitable decline across every system in the body.

She also describes how XPRIZE Healthspan, a $101 million, seven-year global competition, is testing therapies designed to restore muscle, cognitive, and immune function in older adults. Rather than funding proposals up front, the competition rewards teams for demonstrated results, using shared protocols and central laboratories so therapies can be compared head to head for the first time. The approach has drawn unexpected teams from around the world, including a high school team from Malaysia.

The conversation then turns to some of the field’s central debates: whether aging should be classified as a disease, how lifestyle interventions compare with new drugs and biologics, and how to hold the consumer longevity market to real evidentiary standards. Dr. Justice also shares why she will not try any of the therapies in her own competition until judging is complete.

The episode closes with a look at how far human lifespan might be extended, and how society will need to rethink purpose, work, and technology as populations age.

Key Topics Covered:

• The gap between lifespan and healthspan
• How the XPRIZE Healthspan competition model works
• Why aging is a risk factor rather than a disease
• Lifestyle interventions vs. new longevity therapies
• Scientific objectivity and evidence in the consumer longevity market
• The limits of lifespan extension and their societal implications

This is a practical, science-driven discussion for anyone interested in longevity, healthy aging, and the future of aging research.

Chapters:

0:00 – Introduction
3:37 – Why Has Interest in Longevity Surged?
7:02 – Healthspan vs. Lifespan
14:35 – Inside the XPRIZE Healthspan Competition
24:26 – Lifestyle Interventions vs. New Therapies
37:49 – Is Aging a Disease?
48:30 – How Long Could Humans Live?
56:01 – Closing Remarks

Frequently Asked Questions:

What is the difference between lifespan and healthspan?

Lifespan is how long we live. Healthspan is how many of those years we spend in good health. Dr. Justice notes that average lifespan in Western populations has grown by about 30 years over the past century, but healthspan has not kept pace. The result is a gap of roughly 12 years in most Western countries, and 17 to 20 years in some countries where people live even longer.

Why has interest in longevity grown so much in recent years?

Dr. Justice points to several forces arriving at once: populations living far longer than ever before, multiple generations who have cared for aging parents and seen what they don’t want the end of life to look like, and two decades of research showing that aging can be slowed in worms, flies, mice, and even non-human primates.

What is XPRIZE Healthspan?

XPRIZE Healthspan is a $101 million, seven-year global competition launched in 2023. Teams must develop a therapy that restores muscle, cognitive, and immune function in older adults, with measurable improvements equivalent to 10, 15, or 20 years. Therapies can be anything from a single drug to a biologic, gene therapy, or combination approach.

How is a prize competition different from a research grant?

With a grant, funding comes first and the work follows. In a prize competition, teams have to demonstrate results before they are awarded. XPRIZE Healthspan teams also share a common data coordinating center at the University of Utah and central laboratories coordinated through UC San Diego’s Stein Institute for Research on Aging, which makes head-to-head comparisons between therapies possible for the first time.

Is aging a disease?

Dr. Justice argues it is not. Labeling aging a disease would carry consequences such as stigma, liability, and workforce implications, and it would undercut the value of prevention. She describes aging as a progressive, universal, intrinsic decline in physiological integrity that raises the risk of disease, disability, and death. In her analogy, aging is the chain, and a disease is one broken link.

Which matters more for healthy aging: lifestyle or new therapies?

Dr. Justice’s answer is both. Proven lifestyle measures like exercise, diet, and preventive care should be the standard any new therapy has to beat, in effectiveness as well as cost and access. XPRIZE Healthspan finalists range from engineered extracellular vesicles and gene therapies to a telehealth platform delivering repurposed drugs, supplements, and health coaching.

Does Dr. Justice use longevity therapies herself?

No. She focuses on the basics: daily exercise and meditation, a walking treadmill desk, sleep, and regular health screenings. To protect her scientific objectivity, she will not try any therapy being tested in the competition until it has concluded.

How long could humans realistically live?

Dr. Justice cites recent computer modeling suggesting that, even if every known aging pathway were targeted under ideal conditions, maximum lifespan might extend to around 150 to 190 years, and perhaps as high as 250. That is a limit, not immortality. She adds that society already needs to rethink purpose at every stage of life, regardless of how far lifespan extends.

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