Key Terms
Concise definitions for terms used throughout this guide
The following definitions are provided for quick reference. Full context for each appears in the relevant section of the guide.
AMPK (AMP-Activated Protein Kinase)
A cellular signalling pathway activated by energy scarcity (fasting, caloric restriction, aerobic exercise), promoting autophagy and mitochondrial maintenance. Broadly opposes mTOR signalling.
Autophagy
The cell's internal recycling and clean-up process, clearing damaged proteins and organelles. One of the twelve hallmarks of aging; activated by AMPK and caloric restriction.
Biological Age
An estimate of physiological aging based on biomarkers, as distinct from chronological age (years since birth). Epigenetic clocks are the research-grade standard measurement method.
Cellular Senescence
The state where cells stop dividing but don't die off — instead they linger and leak inflammatory signals that damage nearby healthy tissue. One of the twelve hallmarks of aging.
Epigenetic Clock
A method of estimating biological age from patterns of DNA methylation in a tissue sample. Responsive to interventions like caloric restriction, making it a useful research outcome measure.
Hallmarks of Aging
A framework of twelve distinct, interconnected biological mechanisms driving aging, including genomic instability, telomere attrition, cellular senescence, and mitochondrial dysfunction.
Healthspan
The number of years spent in good physical and cognitive function, free of significant disability — distinct from lifespan (total years lived), and the primary target of most interventions in this guide.
mTOR (Mechanistic Target of Rapamycin)
A cellular signalling pathway activated by nutrient availability and mechanical loading, driving growth and tissue repair. The target of rapamycin, which inhibits it.
Sarcopenia
The age-related loss of muscle mass, strength, and function, now formally defined with clinical diagnostic criteria. Resistance training is the primary evidenced intervention against it.
VO2 Max
The maximum rate of oxygen utilisation during exercise, and the strongest single objective predictor of all-cause mortality identified in large clinical cohorts.