4-7-8 Breathing
4-7-8 breathing is a pattern popularized by Andrew Weil: inhale 4 seconds, hold 7 seconds, exhale 8 seconds through pursed lips. The extended exhale s…
Lexique
74 définitions claires sur la longévité, les hormones, le métabolisme et la chronobiologie. avec les liens vers les guides approfondis.
4-7-8 breathing is a pattern popularized by Andrew Weil: inhale 4 seconds, hold 7 seconds, exhale 8 seconds through pursed lips. The extended exhale s…
Allostatic load is the cumulative wear on the body from chronic stress and repeated cycles of physiological adaptation. It represents the biological c…
AMPK (AMP-activated protein kinase) is the cell's master energy sensor. It activates when cellular energy is low — during exercise, fasting, or calori…
Apigenin is a flavonoid concentrated in chamomile, parsley, and celery. It inhibits CD38 (an enzyme that degrades NAD+), helping preserve cellular NAD…
ApoB (apolipoprotein B) is a protein found on every atherogenic lipoprotein particle — LDL, VLDL, IDL, and Lp(a). Because each of these particles carr…
Autophagy is the cellular self-cleaning process by which cells identify, dismantle, and recycle damaged proteins and organelles. It is a critical long…
Berberine is a plant alkaloid found in barberry and goldenseal with potent effects on glucose metabolism. It activates AMPK, improves insulin sensitiv…
BHMT (betaine-homocysteine methyltransferase) is an enzyme that clears homocysteine by attaching a methyl group from betaine (TMG). It is an alternati…
Box breathing is a 4-second equal-ratio pattern: inhale 4, hold 4, exhale 4, hold 4. Used by military, athletes, and first responders for rapid stress…
Cellular senescence is a state of permanent cell cycle arrest in which a cell can no longer divide but remains metabolically active. Senescent cells a…
Chronobiology is the science of biological timing — how living organisms organize physiological processes across time. In practice, it encompasses cir…
Cold plunge (deliberate cold water immersion at 10–15°C for 2–5 minutes) activates PGC-1α, releases norepinephrine 2–3x baseline, stimulates brown adi…
Collagen is the most abundant protein in the body — the structural scaffold of skin, tendons, ligaments, cartilage, and bone. Collagen synthesis decli…
Cortisol is the body's primary stress hormone, produced by the adrenal glands. In healthy patterns it peaks in the morning to mobilize energy and decl…
The cortisol awakening response (CAR) is the sharp, programmed rise in cortisol — typically 50–150% above baseline — that occurs in the first 20–45 mi…
Creatine is an amino acid derivative stored in muscle as phosphocreatine, used to rapidly regenerate ATP during high-intensity effort. It is one of th…
C-reactive protein (CRP) is an inflammatory marker produced by the liver in response to IL-6 signaling. It is one of the most widely measured inflamma…
Curcumin is the primary active compound in turmeric, with broad anti-inflammatory effects through NF-κB suppression and Nrf2 activation. Its major wea…
CYP1A1 is a phase I liver enzyme that metabolizes estrogens — and its activity determines whether estrogens are processed through the protective 2-hyd…
Deep sleep (slow-wave sleep) is the most physically restorative sleep stage. It is when growth hormone is released, the brain's waste-clearance system…
DNA methylation is the addition of methyl groups to cytosine bases in DNA, typically at CpG sites. It is the most studied epigenetic modification and …
Epigenetics is the study of heritable changes in gene expression that do not involve changes to the DNA sequence itself. Epigenetic modifications — in…
Estrogen is the primary female sex hormone produced mainly by the ovaries. It regulates the menstrual cycle, maintains bone density, supports cardiova…
Fasting insulin measures circulating insulin after an 8–12 hour fast. It is a more sensitive early marker of insulin resistance than fasting glucose o…
Ferritin is the body's iron storage protein — the best single marker of iron stores. Women are uniquely prone to low ferritin through menstruation, wi…
Traditional Finnish sauna (80–90°C, 15–30 minutes, 4+ times per week) has some of the strongest longevity evidence of any lifestyle intervention. The …
The follicular phase spans from day 1 of menstruation to ovulation — typically 12–16 days. Estrogen rises progressively, supporting improved insulin s…
GLUT4 is the insulin-responsive glucose transporter in muscle and fat cells. When insulin binds its receptor, GLUT4 moves from intracellular storage t…
Glycation is the non-enzymatic attachment of sugars to proteins, lipids, or DNA, creating Advanced Glycation End-products (AGEs). AGEs crosslink tissu…
Glycine is the smallest amino acid and an inhibitory neurotransmitter in the brain. Supplementation (3g pre-bed) has direct evidence for improving sle…
The gut microbiome is the ecosystem of trillions of microorganisms inhabiting the gastrointestinal tract. It regulates inflammation, immune function, …
HbA1c is hemoglobin with sugar attached — a measurement of how much glucose has glycated red blood cells over the previous ~3 months. It is the standa…
Homocysteine is an amino acid intermediate in the methylation cycle. Elevated levels signal impaired methylation, typically due to inadequate B vitami…
The Horvath clock is an epigenetic biological age calculator developed by Steve Horvath in 2013. It measures DNA methylation at hundreds of CpG sites …
HRV, or heart rate variability, is the variation in time between consecutive heartbeats. A high HRV reflects a responsive, well-recovered nervous syst…
hs-CRP (high-sensitivity C-reactive protein) is a refined CRP test that detects low-grade chronic inflammation that standard CRP testing misses. It is…
Heat shock proteins (HSPs) are a family of molecular chaperones that protect cells from stress. HSP70 is the most studied — it prevents protein misfol…
Inflammaging is the chronic, low-grade systemic inflammation that accumulates with age. Unlike acute inflammation (which is protective), inflammaging …
Insulin resistance is a condition in which cells become less responsive to insulin's signaling, requiring the pancreas to produce more insulin to main…
Intermittent fasting (IF) refers to eating patterns that cycle between periods of eating and fasting. It activates autophagy, improves insulin sensiti…
L-theanine is an amino acid found primarily in green tea. It promotes calm focus by increasing alpha brainwave activity, modulating GABA and dopamine,…
Lactobacillus plantarum 299v is a specific probiotic strain with evidence for reducing IBS symptoms, improving iron absorption, and supporting gut bar…
The lactate threshold is the exercise intensity at which lactate production begins to exceed the body's ability to clear it, causing accumulation in t…
The LH surge is a sharp rise in luteinizing hormone that triggers ovulation approximately 24–36 hours later. It is the cycle's most precise timing sig…
Lipoprotein(a) is an LDL-like particle with an additional apolipoprotein(a) attached, giving it enhanced pro-atherogenic and pro-thrombotic properties…
The luteal phase spans from ovulation to menstruation — typically 12–14 days. Progesterone dominates, raising core body temperature, increasing metabo…
Magnesium is a mineral involved in over 300 enzymatic reactions including ATP production, muscle contraction, nervous system regulation, and DNA synth…
Melatonin is the hormone produced by the pineal gland in response to darkness. It signals nighttime to the body's circadian clocks, initiates sleep on…
Metabolic flexibility is the ability to efficiently switch between burning carbohydrates and fats depending on fuel availability and energy demand. It…
Methylcobalamin is the active, coenzyme form of vitamin B12 — the form your body uses directly for methylation and nervous system function. It is pref…
Methylfolate (5-MTHF) is the biologically active form of folate — the form your cells actually use. People with MTHFR gene variants convert dietary fo…
Mitochondria are the organelles responsible for producing ATP — the cell's energy currency — through aerobic respiration. Mitochondrial health and den…
Mitochondrial biogenesis is the process of creating new mitochondria within cells. It is orchestrated by PGC-1α, stimulated by exercise, cold exposure…
mTOR (mechanistic Target of Rapamycin) is the cell's master growth sensor. It activates in response to nutrients — particularly protein and insulin — …
NAD+ (nicotinamide adenine dinucleotide) is a coenzyme essential for mitochondrial energy production, DNA repair, and activation of sirtuins — longevi…
NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells) is the master transcription factor of inflammation. When activated, it drives p…
The Norwegian 4x4 is a high-intensity interval protocol: four 4-minute intervals at 85–95% max heart rate, with 3-minute active recovery between. It i…
Nrf2 (Nuclear factor erythroid 2-related factor 2) is the master regulator of cellular antioxidant defense. It turns on the production of glutathione,…
Omega-3 fatty acids are essential polyunsaturated fats that the body cannot synthesize. EPA and DHA — the long-chain forms found in fatty fish — are d…
The Omega-3 Index measures EPA + DHA as a percentage of total fatty acids in red blood cell membranes. It reflects tissue omega-3 status over approxim…
The one-carbon cycle is a network of interconnected biochemical pathways that transfer methyl groups for DNA methylation, neurotransmitter synthesis, …
PGC-1α (PPARγ coactivator 1-alpha) is the master regulator of mitochondrial biogenesis. It integrates signals from exercise, cold, fasting, and stress…
Polyphenols are bioactive plant compounds with antioxidant, anti-inflammatory, and signaling properties. They include flavonoids, resveratrol, curcumi…
A 10–15 minute walk within an hour of eating blunts the postprandial glucose excursion by 30–50%. It works by activating muscle contraction-mediated G…
Progesterone is a sex hormone produced primarily in the corpus luteum after ovulation. It prepares the uterus for pregnancy, counterbalances estrogen,…
Quercetin is a flavonoid concentrated in onions, capers, apples, and berries. It has anti-inflammatory, antihistamine, and senolytic properties. In re…
Sirtuins are a family of seven proteins (SIRT1–SIRT7) that regulate gene expression, mitochondrial function, DNA repair, and cellular stress resistanc…
Stem cell exhaustion is the age-related decline in the number and function of tissue stem cells. As stem cells lose their regenerative capacity, tissu…
Sulforaphane is a sulfur-containing compound concentrated in broccoli sprouts. It is one of the most potent natural Nrf2 activators known, upregulatin…
Telomeres are the protective caps at the ends of chromosomes, analogous to the plastic tips on shoelaces. They shorten with each cell division and are…
Testosterone is an androgen present in women at lower levels than men but with critical roles in muscle maintenance, bone density, libido, energy, and…
TMG (trimethylglycine, also called betaine) is a compound that donates methyl groups through the BHMT pathway — an alternative to the folate-dependent…
VO2 max is the maximum volume of oxygen your body can consume per minute during maximal exercise. It is the gold-standard measure of aerobic fitness a…
Zone 2 is a training intensity where you work aerobically at a pace you can sustain for long periods while still holding a conversation. It is the pri…
Ava Longevity · Built on the Ava Method · MMXXV