Caloric restriction refers to reducing daily caloric intake without malnutrition, a strategy shown to extend lifespan in animal models. Topol notes that human evidence is more modest, with studies linking moderate restriction (12–14%) to reduced biological age and improved immune function. The concept represents one of the oldest and most studied interventions in the science of longevity.

Centenarians—people who live to age 100 or beyond—serve as both statistical markers and living case studies of longevity. Topol highlights projections that the number of US centenarians will increase dramatically by 2060, reflecting demographic changes rather than biomedical breakthroughs. Their example illustrates the possibility of extended lifespan and underscores persistent challenges in extending health span.

This concept, first proposed by James Fries in the 1980s, argues that the period of illness or disability before death can be shortened even if lifespan is not greatly extended. In the book, Topol contrasts this idealized vision with current evidence, which suggests morbidity is often deferred rather than compressed. The metaphor of dying by “falling off a cliff” after a long life of good health encapsulates the aspirational vision of this model.

Digital biology refers to the fusion of biology with computational modeling, AI, and large-scale data analysis. Topol calls the 21st century a potential golden era in medicine, where protein language models and genome editing can make biology “engineering, not science” (334). The term “digital biology” captures the transformative potential of technology to accelerate discoveries in longevity research.

Epigenetic reprogramming involves resetting cellular markers of age by altering gene expression without changing DNA sequence. Building on the discovery of Yamanaka factors, researchers like Juan Carlos Izpisua Belmonte have experimented with “partial reprogramming” to rejuvenate cells while retaining their identity. In Super Agers, this strategy symbolizes both promise and peril, since uneven reprogramming risks cancer while successful tuning could extend health span.

Frailty describes the increased vulnerability to illness, disability, and death that often accompanies old age. Topol notes that despite the existence of more centenarians, frailty remains largely unconquered, with chronic conditions accumulating in late life. The term grounds his argument that expanding lifespan without addressing frailty risks adding years of suffering rather than vitality.

Originally developed for diabetes, GLP-1 receptor agonists like semaglutide have emerged as powerful treatments for obesity and related conditions. Topol highlights them as examples of how decades of failed interventions can give way to breakthroughs with wide-ranging benefits for longevity. Their affordability and access remain pressing concerns, making them a case study in both biomedical promise and systemic inequity.

The hallmarks of aging are 12 interconnected biological processes, such as genomic instability, telomere shortening, and cellular senescence. First codified in 2013 and updated in 2023, they provide a framework for interventions targeting specific mechanisms of decline. In the book, Topol uses the hallmarks to show how research is moving from descriptive biology toward actionable therapeutics.

HALE measures the average number of years a person is expected to live in good health, in contrast to raw life expectancy (LE). Topol stresses that the gap between LE and HALE is widening in the US, with most Americans developing chronic conditions soon after age 65. The concept anchors the book’s central distinction between simply living longer and truly aging well.

Immunosenescence is the gradual decline of immune function with age, marked by reduced responsiveness and chronic inflammation. Topol identifies the immune system as a crucial target for future interventions, with “immunomes,” or maps of an individual’s specific immune system, offering a way to measure and potentially rejuvenate immune health. This term highlights how vulnerability to infection and cancer intersects with longevity science.

Coined by futurist Ray Kurzweil, this term refers to the point when medical advances add more than a year of life expectancy per calendar year, theoretically allowing humans to outrun aging. Topol includes it as an example of extreme speculative optimism, contrasting its bold vision with the slower, incremental reality of medical progress. The idea reflects cultural hopes for immortality, even if it remains scientifically implausible.

Organ clocks are biomarker systems that estimate the biological age of specific organs such as the brain, heart, or kidneys. Research cited in Super Agers shows that individuals often have one or two organs aging faster than others, which predicts related diseases. These tools suggest that personalized, organ-specific interventions may be more realistic than whole-body rejuvenation.

Senolytics are drugs designed to selectively eliminate senescent “zombie” cells that no longer divide but instead secrete inflammatory molecules. While promising in animal models, senolytics pose risks of collateral damage and inflammation in humans. Topol presents them as emblematic of the trade-offs in anti-aging interventions, which must balance potential rejuvenation with safety concerns.