AFib (Atrial Fibrillation)
An irregular, often rapid heart rhythm originating in the heart's upper chambers, one of the most common cardiac conditions detectable by consumer wearables through FDA-cleared algorithms.
Longevity Glossary
Plain-English definitions for the terms, concepts, and frameworks used in longevity science and healthspan research.
A
AI Hallucination
An instance where an AI system generates false or fabricated information, a nonexistent citation, an incorrect dosage, a misidentified condition, and presents it with the same confident tone it uses for accurate information.
B
Biological Age
An estimate of how old the body is functionally, based on objective biological measurements, as opposed to chronological age, which simply counts years since birth.
Biomarker
A measurable biological characteristic that indicates the state of a biological process, disease condition, or response to an intervention. In longevity science, biomarkers are used to track aging and assess healthspan.
C
Continuous Glucose Monitor (CGM)
A wearable sensor that measures glucose levels in real time throughout the day via a small filament under the skin, historically prescription-only, now increasingly available in over-the-counter wellness versions.
D
Digital Biomarker
A measurable, objective signal collected from a digital device, a wearable, smartphone sensor, or implant, that has been clinically validated to correlate with a specific health outcome.
E
Epigenetic Clock
A biological age measurement tool that uses patterns of DNA methylation, chemical modifications to DNA that change predictably with age, to estimate a person's biological age.
F
FDA Clearance
Authorization from the U.S. Food and Drug Administration allowing a medical device or software tool to be marketed after demonstrating it is as safe and effective as a legally marketed comparator device.
H
Healthspan
The period of life spent in good health, with physical strength, cognitive function, mobility, and independence intact. Distinct from lifespan, which is simply the total years lived.
Heart Rate Variability (HRV)
The variation in time between consecutive heartbeats, used as a proxy for autonomic nervous system balance, recovery status, and stress response in wearable health tracking.
L
Longevity
The capacity to live a long, healthy life. In modern science, longevity refers not just to maximum lifespan but to the extension of healthspan, the years lived in full physical and cognitive health.
R
Retrieval-Augmented Generation (RAG)
A technique that forces an AI model to pull information from a specific, verifiable source, a medical database, a set of guidelines, a curated literature index, before generating an answer, rather than relying only on patterns learned during training.