The physiology underneath every protocol. How the cells, the metabolic state, the cardiovascular system, the circadian rhythm, and the nervous system actually work, and where to intervene. The concepts that connect the compounds.
Metabolic state.
Insulin sensitivity, fuel substrate flexibility, and the metabolic levers that move every chronic-disease risk together.
Glycation
The non-enzymatic reaction of sugars with proteins. The upstream process that creates AGEs.
AGEs (Advanced Glycation End Products)
Sugar-protein cross-link byproducts. Accumulate with age, drive stiffness in tissue, and accelerate cardiovascular decline.
Brown Adipose Tissue (BAT)
Thermogenic fat. Burns calories to produce heat. Activated by cold exposure.
Visceral Fat
Fat surrounding internal organs. The metabolically active, inflammation-driving fat that matters for disease risk.
CGM (Continuous Glucose Monitor)
Wearable glucose sensor. The most informative biofeedback device for metabolic health.
NAD+/NADH Ratio
The redox indicator of cellular energy state. NAD+ is the oxidized form; NADH the reduced form.
Polyphenols
Plant secondary metabolites with broad health effects. The 'colored compound' family — flavonoids, anthocyanins, lignans, more.
Glucose Sink
Muscle's role in clearing blood glucose. The biggest single reason resistance training is longevity work.
Anti-Inflammatory
A protocol or compound that lowers systemic inflammation. The most modifiable longevity lever.
Insulin Resistance
Cells stop responding to insulin. The root state behind most metabolic disease.
Glycemic Load
Glycemic index × carb amount. The honest metric for blood-sugar impact of a meal.
Ketosis
A metabolic state where the body runs primarily on ketones instead of glucose.
Intermittent Fasting
Time-restricted eating. Less about the fast itself, more about meal timing and the eating window.
Insulin Sensitivity
The opposite of resistance. Cells respond well to small insulin signals.
Metabolic Flexibility
The ability to switch between burning glucose and burning fat as needed. A defining marker of metabolic health.
Cellular & longevity.
Autophagy, epigenetics, mitochondrial function, and the cellular biology that underlies aging.
Biological Age
An estimate of physiological age, distinct from chronological age. The objective of longevity practice.
Cellular Senescence
Cells stop dividing but don't die. Accumulate with age and drive inflammaging via the SASP.
Glutathione
The master endogenous antioxidant. Tripeptide of glutamate, cysteine, and glycine.
DNA Methylation
Chemical tags on DNA that regulate gene expression. The substrate of epigenetic aging clocks.
mTOR
Mechanistic target of rapamycin. The central growth-vs-conservation pathway. The bull's-eye of longevity intervention.
NK Cells (Natural Killer Cells)
Innate immune cells that kill virus-infected and cancer cells. NK activity declines with age and chronic stress.
ROS (Reactive Oxygen Species)
Free radicals from oxygen metabolism. Damage at chronic excess, signaling at controlled levels.
REM Sleep
Rapid Eye Movement sleep. Where emotional processing, learning consolidation, and dreaming happen.
Sarcopenia
Age-related loss of muscle mass and function. The single biggest reason resistance training is non-negotiable.
Senolytics
Compounds that selectively kill senescent cells. The leading edge of geroscience.
SIRT1 (Sirtuins)
NAD+-dependent deacetylase enzymes. Activated by caloric restriction; modulate metabolism, DNA repair, and aging.
Stem Cells
Undifferentiated cells that can self-renew and become specialized. The biological reserve pool. Declines with age.
Telomeres
Protective caps on chromosome ends. Shorten with cell division; below a critical length, cells senesce.
Epigenetics
How DNA expression changes without changing the underlying sequence. The control layer.
Autophagy
The cell's self-cleaning process. Recycles damaged components into raw materials.
Neuroplasticity
The brain's ability to rewire. Use-dependent throughout life.
Mitochondria
The cellular power plants. Make ATP. Run signaling. Drive aging when they fail.
Inflammation
The body's response to threat. Acute is healing; chronic is destruction.
Healthspan
Years of healthy, functional living. The metric that should replace lifespan.
Cardiovascular.
Blood flow, vascular health, heart fitness, and the bone-density story that runs alongside it.
Coronary Artery Calcium Score (CAC)
Cardiac CT-based score. The single best non-invasive marker of established coronary atherosclerosis.
Endothelial Function
The lining of blood vessels. Its capacity to vasodilate is the earliest reversible CV warning.
Cerebral Blood Flow
Brain perfusion. Declines with age and dysfunction; supports cognitive performance and dementia risk.
Vagal Tone
Parasympathetic baseline. Measured via HRV. Higher = better autonomic balance and resilience.
Heart Health
The cardiovascular system's reserve capacity. The single biggest determinant of all-cause mortality.
Blood Flow
The transport system. Delivery of oxygen, nutrients, and signaling molecules to every tissue.
Bone Mineral Density
The mass per unit volume of bone tissue. Determines fracture risk; declines without resistance.
Nitric Oxide
Vasodilator signaling molecule. Endothelium-derived; declines with age.
Recovery & circadian.
Sleep architecture, light timing, the microbiome, and the lymphatic plumbing that keep the system clean.
Allostatic Load
Cumulative wear-and-tear from chronic stress response. The integrated cost of unresolved demand.
Chronotype
Your genetically influenced sleep-wake preference. The mismatch with schedule drives social jet lag and metabolic strain.
Glymphatic System
The brain's overnight cleanup network. CSF-mediated waste clearance that runs primarily during deep sleep.
Heat Shock Protein (HSP)
Stress-response chaperones. Protect protein folding under thermal, hypoxic, or oxidative challenge.
Hormesis
Beneficial adaptation from low-dose stress. The mechanism behind exercise, cold, heat, fasting, and most longevity interventions.
Hyperbaric Oxygen (HBOT)
Pressurized oxygen therapy. Approved indications plus emerging off-label longevity protocols.
Inflammaging
Chronic low-grade inflammation that accumulates with age. The integrated driver of most age-related disease.
Sauna
Dry heat exposure. Trains cardiovascular reserve, raises BDNF, induces HSPs. The cleanest hormetic data of any modality.
Sleep Latency
Time from lights-out to sleep onset. A diagnostic of sleep pressure and sleep hygiene.
Circadian Rhythm
The body's 24-hour internal clock. Hormones, metabolism, mood, and cognition all run on it.
Microbiome
The trillions of microbes in the gut. Affects immunity, mood, metabolism, and inflammation.
Lymphatic Drainage
The body's filtration and immune transport network. Moved by muscle, not the heart.
Deep Sleep
Slow-wave sleep. Where physical recovery, memory consolidation, and glymphatic clearance happen.
Cold Plunge
Brief immersion in cold water. Hormetic stress for recovery, dopamine, and mitochondrial function.
Mind & nervous system.
Neurotransmitters, cognitive reserve, breathwork, and the practices that move the autonomic nervous system.
ATP
Adenosine triphosphate. The cellular energy currency. Every effortful thing you do is paid for in ATP.
Cognitive Health
The integrated state of attention, memory, executive function, and processing speed.
Breathwork
Deliberate breathing patterns to shift physiology. The fastest lever into the autonomic nervous system.
Dopamine
Reward and motivation neurotransmitter. Not pleasure itself; the signal to pursue.
Flow State
The 'in the zone' state. Full absorption in a challenging task, with time perception altered.
Cognitive Reserve
The brain's structural and functional buffer against decline. Built through education, challenge, and complexity.
GABA
The primary inhibitory neurotransmitter. Why benzos, alcohol, and sleep aids work.
Endorphins
Endogenous opioid peptides. The body's own pain modulators and reward chemicals.