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health Glossary
Explore clear, concise definitions for health terms. Each entry is written for fast comprehension and quick reference.
Featured health Terms
Start with the most referenced concepts
Aerobic Exercise
Physical exercise of low to high intensity that depends primarily on the aerobic energy-generating process.
Amino Acid
Organic compounds that combine to form proteins.
Anabolic
Metabolic pathways that construct molecules from smaller units.
Anaerobic Exercise
Physical exercise intense enough to cause lactate to form.
Atrophy
The wasting away or decrease in size of an organ or tissue in the body.
BMI (Body Mass Index)
A screening tool used to estimate the amount of body fat a person has based on their height and weight.
Aerobic Exercise
Physical exercise of low to high intensity that depends primarily on the aerobic energy-generating process.
Amino Acid
Organic compounds that combine to form proteins.
Anabolic
Metabolic pathways that construct molecules from smaller units.
Anaerobic Exercise
Physical exercise intense enough to cause lactate to form.
Atrophy
The wasting away or decrease in size of an organ or tissue in the body.
BMI (Body Mass Index)
A screening tool used to estimate the amount of body fat a person has based on their height and weight.
BMR (Basal Metabolic Rate)
The number of calories your body burns while at rest to maintain basic life functions like breathing and circulation.
Body Fat Percentage
The total mass of fat divided by total body mass, multiplied by 100. It is a more accurate measure of fitness than BMI.
Burnout
A state of emotional, physical, and mental exhaustion caused by excessive and prolonged stress.
Cardiac Output
The amount of blood pumped by the heart per minute.
Catabolic
Metabolic pathways that break down molecules into smaller units that are either oxidized to release energy or used in other anabolic reactions.
Chronotype
The natural inclination of your body to sleep at a certain time, also known as your "body clock."
Circadian Rhythm
Physical, mental, and behavioral changes that follow a 24-hour cycle.
Cortisol
A steroid hormone that regulates a wide range of processes throughout the body, including metabolism and the immune response.
Gestation
The process of carrying or being carried in the womb between conception and birth.
Glycemic Index (GI)
A relative ranking of carbohydrate in foods according to how they affect blood glucose levels.
Glycemic Load (GL)
A number that estimates how much the food will raise a person's blood glucose level after eating it.
Glymphatic System
A waste clearance system in the brain that removes toxic proteins (like beta-amyloid) primarily during sleep.
Heart Rate
The speed of the heartbeat measured by the number of contractions (beats) of the heart per minute (bpm).
HIIT (High-Intensity Interval Training)
A training technique in which you give all-out, one hundred percent effort through quick, intense bursts of exercise, followed by short, sometimes active, recovery periods.
Homeostasis
The state of steady internal, physical, and chemical conditions maintained by living systems.
Hydration
The process of causing something to absorb water, or the state of being hydrated.
Hypertension
High blood pressure.
Hypertrophy
The enlargement of an organ or tissue from the increase in size of its cells.
Macronutrient
Nutrients required in large amounts that provide energy.
Macros (Macronutrients)
The three main nutrients that provide energy: Protein, Carbohydrates, and Fats.
Medicaid
A health care program that assists low-income families or individuals in paying for doctor visits, hospital stays, long-term medical, etc.
Medicare
A US federal health insurance program for people who are 65 or older.
Melatonin
A hormone primarily released by the pineal gland at night, and has long been associated with control of the sleep–wake cycle.
Metabolism
The chemical processes that occur within a living organism in order to maintain life.
Micronutrient
Chemical elements or substances required in trace amounts for the normal growth and development of living organisms.
Mitochondria
Membrane-bound cell organelles (mitochondrion, singular) that generate most of the chemical energy needed to power the cell's biochemical reactions.
NEAT
Non-Exercise Activity Thermogenesis. The energy expended for everything we do that is not sleeping, eating, or sports-like exercise.
Neuroplasticity
The ability of the brain to form and reorganize synaptic connections, especially in response to learning or experience or following injury.
Nocebo
A detrimental effect on health produced by psychological or psychosomatic factors such as negative expectations of treatment or prognosis.
Placebo
A substance or treatment with no active therapeutic effect.
Placebo Effect
A beneficial effect produced by a placebo drug or treatment, which cannot be attributed to the properties of the placebo itself, and must therefore be due to the patient's belief in that treatment.
Protein
Large biomolecules and macromolecules that comprise one or more long chains of amino acid residues.
REM Sleep
Rapid Eye Movement sleep, a unique phase of sleep in mammals and birds, characterized by random rapid movement of the eyes, accompanied by low muscle tone throughout the body, and the propensity of the sleeper to dream.
Resting Heart Rate (RHR)
The number of times your heart beats per minute while you are at rest.
Revenge Bedtime Procrastination
A psychological phenomenon where people who lack control over their daytime life refuse to sleep early to regain a sense of freedom at night.
Sarcopenia
The age-related progressive loss of muscle mass and strength.
Serotonin
A key hormone that stabilizes our mood, feelings of well-being, and happiness.
Sleep Apnea
A serious sleep disorder in which breathing repeatedly stops and starts.
Sleep Cycle
An oscillation between the slow-wave and REM (paradoxical) phases of sleep.
Sleep Inertia
The state of grogginess and impaired cognitive performance experienced immediately after waking up.
Social Jetlag
The discrepancy between an individual's biological clock and their social clock (work/school schedules).
Stroke Volume
The volume of blood pumped from the left ventricle per beat.
Subcutaneous Fat
The jiggly fat visible just under the skin.
TDEE (Total Daily Energy Expenditure)
The total number of calories you burn in a day, including exercise and daily activity.
TEF (Thermic Effect of Food)
The energy required for digestion, absorption, and disposal of ingested nutrients.
Trimester
A period of three months, especially as a division of the duration of pregnancy.