Health and Fitness Glossary of Terms (Terminology)

When it comes to health and fitness there are many terms that you may not know the definition of. This health and fitness glossary of terms is meant to help you with understanding the content of this site as well as potentially other health and fitness content. Especially if you are a beginner or intermediate-level fitness enthusiast. That being said we have gathered up more than 100 of the terms you may hear or see us use in content and we have provided the definition for these terms. This health and fitness glossary of terms is informational and meant to help if needed.

The health and fitness glossary of terms below is thorough but also we tried to break it into plain English so it’s more understandable. We mixed our explanations with dictionary definitions to create this fitness glossary of terms to make it understandable and easily searchable. You can either scroll through by using the buttons and scrolling to look through the glossary table for fitness and health terms or you can use the search bar to speed up the results.

Term (Word)Definition (Description)
Activities of Daily Living (ADLs)Physical tasks of everyday living, such as bathing, and walking up the stairs. ADLs are usually factored in to a person's basal metabolic rate, so tracking calories burned for these types of movement isn't recommended when trying to lose weight.
Aerobic exerciseAny rhythmic activity that increases the body's need for oxygen by using large muscle groups continuously for at least 10 minutes. The term aerobic means “with oxygen.”
Agonist muscleA muscle that is very effective in causing a certain joint movement. Also called the prime mover. On a biceps curl, the biceps is the agonist muscle that flexes the elbow joint.
AmenorrheaThe absence of menstruation, is commonly found in women with a very low body fat percentage and/or exercise excessively.
Anaerobic exerciseshort lasting, high intensity activity, where the demand for oxygen from the exercise exceeds the oxygen supply.
Angina pectorisChest pain due to lack of blood flow (oxygen) to the heart.
Antagonist muscleA muscle that causes movement at a joint in a direction opposite to that of the joint’s agonist (prime mover).
Beta-blockersType of medication that reduces heart rate. Exercisers who take beta-blockers will have a lower heart rate at rest and during exercise, so the target heart rate formula cannot be used in this case.
Bioelectrical impedanceThis method of measuring body composition is based on the fact that the lean tissue of the body is much more conductive due to its higher water content than fat tissue. The more lean tissue present in the body, the greater the conductive potential, measured in ohms.
Body compositionAmount of fat vs. lean muscle tissue in the human body.
Body Mass Index (BMI)Measure of the relationship between height and weight; calculated by dividing weight in kilograms by height in centimeters squared.
CaffeineA stimulant found in coffee, tea, chocolate, and some soft drinks that increases heart contractions, oxygen consumption, metabolism, and urinary output.
CalisthenicsExercising using one’s own body weight which helps develop muscular tone.
Cardiorespiratory fitnessThe measure of the heart’s ability to pump oxygen-rich blood to the muscles. Also called cardiovascular or aerobic fitness.
Cardiovascular systemA complex system consisting of the heart and blood vessels; transports nutrients, oxygen, and enzymes throughout the body and regulates temperature, water levels of cells, and acidity levels of body components.
Circuit trainingTakes the participant through a series of exercise stations (which could also include strength training), with relatively brief rest intervals between each station. The purpose is to keep the heart rate elevated near the aerobic level without dropping off. The number of stations may range from 4 to 10.
Concentric muscle actionForce produced while the muscle is shortening in length.
Continuous trainingThis is the most common type of sustained aerobic exercise for fitness improvement, slowly adding more time to the workout to increase endurance.
Cool downLowering of body temperature following vigorous exercise. The practice of cooling down after exercise involves slowing down your level of activity gradually.
CoreA muscle group comprised of the abdominals, lower back, obliques, and hips.
CortisolA hormone secreted by the adrenal gland that makes stored nutrients more readily available to meet energy demands. These hormone levels increase under stress, which can stimulate your appetite, leading to weight gain or difficulty losing weight.
Cross-trainingAn individualized combination of all aerobic-training methods, characterized by a variety of intensities and modes.
Detraining PrincipleThis principle says that once consistent exercise stops, you will eventually lose the strength that you built up. Without overload or maintenance, muscles will weaken in two weeks or less.
Diastolic blood pressureThe pressure exerted by the blood on the vessel walls during the resting portion of the cardiac cycle, is measured in millimeters of mercury. The diastolic number is the bottom of the fraction. 120/80 is an average value for normal blood pressure (80 is the diastolic number). Mild high blood pressure is considered to be between 140/90 and 160/95. High blood pressure is defined by a value greater than 160/95.
DOMS (Delayed Onset Muscle Soreness)Muscle soreness or discomfort that appears 12 to 48 hours after exercise. It is most likely due to microscopic tears in the muscle tissue, and it usually requires a couple of days for the repair and rebuilding process to be completed. The muscle tissue grows back stronger, leading to increased muscle mass and strength.
Eccentric contractionA lengthening of the muscle during its contraction; controls the speed of movement caused by another force.
EctomorphA body shape characterized by a narrow chest, narrow shoulders and long, thin muscles.
ElectrolytesSalts (ions) found in bodily fluids. Pertaining to exercise, your body loses electrolytes (sodium, potassium) when you sweat. These electrolytes need to be replaced to keep concentrations constant in the body, which is why many sports drinks include electrolytes.
EndomorphA body shape characterized by a round face, short neck , wide hips, and heavy fat storage.
EndorphinsOpiate-like hormones that are manufactured in the body and contribute to natural feelings of well-being.
EPOC (Excess Post-Exercise Oxygen Consumption)This explains why your breathing rate remains heavy for a few minutes after finishing a workout. Your body needs more oxygen after a workout in order to restore the oxygen stores in the blood and tissues and to meet the oxygen requirements of the heart rate, which is still elevated.
EpinephrineAlso called adrenaline, a hormone that stimulates body systems in response to stress.
EstrogenEstrogen is a hormone that plays various roles in the body. In females, it helps develop and maintain both the reproductive system and female characteristics. Men can also have estrogen as there are different types of estrogen. Estrogen promotes fat storage, so that is why many people who have gained weight or who are gaining fat may consider checking or lowering their estrogen levels.
Ergogenic aidsA substance, appliance, or procedure that improves athletic performance.
Eustress"Good" stress that presents opportunities for personal growth. (Exercise is an example of this. It puts stress on the body and its systems, but the results of this stress are positive.)
Exercise metabolic rate (EMR)The energy expenditure that occurs during exercise.
Fast twitch muscle fibersFibers that are better-suited for high-force, short duration activities because they contain more stores for anaerobic energy utilization.
Fixed resistanceStrength training exercises that provide a constant amount of resistance throughout the full range of motion. Examples include free weights and resistance bands.
FlexibilityThe measure of the range of motion, or the amount of movement possible, at a particular joint.
Graded Exercise Test (Incremental Exercise Test)An exercise test involving a progressive increase in work rate over time. Often graded exercise tests are used to determine the subject’s maximum oxygen consumption or lactic threshold.
Heart Rate Reserve (HRR)Difference between resting and maximal heart rate.
Heat CrampsMuscle cramps that occur during or following exercise in warm or hot weather.
Heat exhaustionA heat stress illness caused by significant dehydration resulting from exercise in warm or hot conditions; frequent precursor to heat stroke.
Heat strokeA deadly heat stress illness resulting from dehydration and overexertion in warm or hot conditions; can cause body core temperature to rise from normal to 100 or 105 degrees Fahrenheit in just a few minutes.
High-density lipoprotein (HDL)Retrieves cholesterol from the body’s cells and returns it to the liver to be metabolized. Also referred to as “good” cholesterol.
High impactActivities that place more stress on the bones and joints, where your limbs are actually making contact with the ground or other surface with force. Examples include: walking, running, step aerobics, and sports that involve impact, like basketball or tennis.
Hydrostatic (underwater) weighingThis method of measuring body composition is considered the “gold standard” and is based on the assumption that density and specific gravity of lean tissue is greater than that of fat tissue. By comparing test subject’s mass measured underwater and out of the water, body composition may be calculated.
HyperplasiaAn increase in the number of cells in a tissue; usually in reference to fat or muscle cells.
HypertrophyAn increase in cell size (girth), usually in reference to fat or muscle cells.
HypothermiaA life-threatening condition in which heat is lost from the body faster than it is produced.
Incremental Exercise Test (Graded Exercise Test)An exercise test involving a progressive increase in work rate over time. Often these tests are used to determine the subject’s maximum oxygen consumption or lactic threshold.
Interval trainingRepeated intervals of exercise interspersed with intervals of relatively light exercise. This type of training provides a means of performing large amounts of high-intensity exercise in a short period of time.
Isokinetic exerciseExercise in which the rate of movement is constantly maintained through a specific range of motion even though maximal force is exerted.
Isometric exerciseAny activity in which the muscles exert force but do not visibly change in length. For example, pushing against a wall or carrying a bag of groceries.
Isotonic exerciseAny activity in which the muscles exert force and change in length as they lift and lower resistance. For example, bicep curls or leg extensions.
Karvonen formulaOne of the most effective methods used to calculate target heart rate. It factors resting heart rate into the equation.
KetosisA condition in which the body adapts to prolonged fasting or carbohydrate deprivation by converting body fat to ketones, which can be used as fuel for some brain activity. The real danger in ketosis is that ketones are acidic, and high levels of ketones make the blood abnormal acid.
Lactic acidOnce thought of as a waste substance that builds up in the muscles when they are not getting enough oxygen, leading to muscle fatigue and soreness. Now, experts believe that lactic acid is beneficial to the body, acting as a "fuel" to help people continue high-intensity (anaerobic) exercise even when oxygen consumption is low.
Lactic thresholdThe point at which the level of lactic acid in the blood suddenly increases (during exercise). This is a good indication of the highest sustainable work rate. Also known as anaerobic threshold.
Lean massTotal weight of your muscle, bone, and all other body organs. (Everything in the body besides fat.)
Low-density lipoprotein (LDL)Transports cholesterol and triglycerides from the liver to be used in various cellular processes. Also referred to as “bad” cholesterol.
Low impactActivities that place less stress on the bones and joints. These are better for people with joint pain, and overweight individuals whose weight can hurt their joints. Examples include: swimming, elliptical, cycling, and other activities where your feet (or other body parts) aren’t touching the ground with force or where you are somehow supported.
Max VO 2(Also referred to as V02 Max) The highest amount of oxygen one can consume during exercise. The higher this number, the more you are cardiovascularly fit and capable of increased levels of intensity.
MesomorphA body shape characterized by a large chest, long torso, solid muscle structure and significant strength.
METAlso known as metabolic equivalent of task. An expression of the energy it takes to sit quietly. It is frequently used as a measure of intensity on cardiovascular machines (treadmill, stationary bike, etc.) For example, moderate intensity activities are those that get you moving fast enough or strenuously enough to burn off three to six times as much energy per minute as you do when you are sitting quietly, measured as 3-6 METs.
Moderate intensityActivities that range from 40-60% of max heart rate. These activities cause a slightly increased rate of breathing, and feel light to somewhat-hard. Individuals doing activity at this intensity can easily carry on a conversation.
Muscle fibersIndividual muscle cells that are the functional components of muscles.
Muscular enduranceThe ability of the muscle to perform repetitive contractions over a prolonged period of time.
Muscular strengthThe ability of the muscle to generate the maximum amount of force.
ObesityA weight disorder generally defined as an accumulation of fat beyond that considered normal for a person based on age, sex, and body type.
One-Rep Max (1 RM)The amount of weight/resistance that can be lifted or moved once, but not twice; a common measure of strength.
Opposing musclesMuscles that work in opposition to the ones you are training. For example, the bicep is the opposing muscle to the triceps; the hamstring is the opposing muscle to the quadriceps.
OsteoporosisA disease characterized by low bone mass and deterioration of bone tissue, which increases risk of fracture.
Overload PrincipleThis principle says that in order to train muscles, they must work harder than they are accustomed to. This “overload” will result in increased strength as the body adapts to the stress placed upon it.
Overuse InjuriesInjuries that result from the cumulative effects of repetitive (day-after-day) stresses placed on tendons, muscles, and joints.
Percent gradeThe measure of the elevation of a treadmill. (Also referred to as incline as well.)
Physical fitnessThe ability to perform regular to vigorous physical activity without great fatigue.
PilatesExercise programs that combine dynamic stretching with movement against resistance.
PlateauPoint in an exercise program where no additional progress is being made (gains in strength, weight loss, increased endurance, etc). One way to break through a plateau is to change the kind of activity you are doing or something about your current activity- adding hills, increasing speed, increasing distance, etc.
PNF stretchingProprioceptive neuromuscular facilitation (PNF) stretching is a static stretch of a muscle immediately after maximally contracting it.
Primary preventionActions designed to stop problems before they start.
PronationTo turn or rotate (the foot) so that the inner edge of the sole bears the body's weight.
Plyometric trainingExercises that enable a muscle to reach maximal force production in as short a time as possible. For example, jumping from a 3 ft. stool to the ground and immediately springing back up to another stool.
Rate of perceived exertion (RPE)Scale of 1-10 that rates how you are feeling (both physically and mentally) as it relates to exercise fatigue.
RepetitionThe number of times an exercise is repeated within a single exercise “set.”
Resistance trainingSee “Strength training in the glossary of terms”
Resting HRRate at which your heart beats at rest (while sitting or being inactive). Low resting heart rates are a good measure of health and fitness.
Resting Metabolic Rate (RMR)Number of calories expended to maintain the body during resting conditions. Also referred to as basal metabolic rate.
SetA basic unit of a workout containing the number of times (repetitions) a specific exercise is done (e.g. do 3 sets of 5 repetitions with 100 pounds).
Shin splintGeneric term used to describe pain in the lower leg, either on the medial (inside) or lateral side (outside) of the shin bone.
Sit and reach testA common fitness test that determines flexibility (of the hamstrings and lower back).
Skinfold caliper testA method of determining body fat whereby folds of skin and fat at various points on the body are grasped between thumb and forefinger and measured with calipers.
Skin fold measurementsThis method of measuring body composition assumes that substantial fat is proportional to overall body fat, and thus by measuring several sites, total body fat may be calculated.
Slow twitch muscle fibersFibers that are better-suited for low-force, long duration activities because they possess more endurance enzymes.
Specificity of Training PrincipleThis principle says that only the muscle or muscle group you exercise will respond to the demands placed upon it. By regularly doing curls, for example, the muscles involved (biceps) will become larger and stronger, but curls will have no effect on the muscles that are not being trained. Therefore, when strength training, it is important to strengthen all of the major muscles.
Static stretchingA low force, high-duration stretch where the muscle is held at the greatest possible length for up to 30 seconds.
Strength training (resistance training)The process of exercising with progressively heavier resistance for the purpose of strengthening the musculoskeletal system.
Systolic blood pressureThe pressure exerted on the vessel walls during ventricular contraction, is measured in millimeters of mercury. The systolic number is the top of the fraction. 120/80 is an average value for normal blood pressure (120 is the systolic number). Mild high blood pressure is considered to be between 140/90 and 160/95. High blood pressure is defined by a value greater than 160/95.
Tai chiAn ancient Chinese form of exercise, widely practiced in the West today, that promotes balance, coordination, stretching, and meditation.
Talk testMethod to ensure you are working out at a level where you can answer a question but not comfortably carry on a conversation. This is a good intensity level for weight loss and improved physical fitness.
TaperingThe process athletes use to reduce their training load for several days prior to competition.
Target heart rate (THR)The recommended range is 60-85% of your maximum heart rate. It represents a pace that ensures you are training aerobically and can reasonably be maintained.
Tension PrincipleThis principle says that tension is created by resistance, which can come from weights, bands, machines, or body weight.
TestosteroneThe steroid hormone produced in the testes; involved in growth and development of muscle mass. Since men have more testosterone than women, they are able to gain muscle mass more easily.
ThyroidEndocrine gland located in the neck that secretes T3 and T4 (hormones), which increase metabolic rate.
Type I muscle fibersFibers that contain large numbers of oxidative enzymes and are highly fatigue resistant (more prevalent in endurance athletes).
Type IIA muscle fibersFibers that contain biochemical and fatigue characteristics that are between Type IIB and Type I fibers (the best of both worlds).
Type IIB muscle fibersFibers that have a relatively small number of mitochondria, a limited capacity for aerobic metabolism, and are less resistant to fatigue than slow fibers (more prevalent in sprinters and power lifters).
Variable resistanceStrength training exercises that change the amount of resistance throughout the full range of motion.
Vigorous intensityActivities above 60% of max heart rate. These activities cause an increased rate of breathing, sweating, and feel somewhat-hard to hard.
Waist to hip ratioA calculation of the proportion of fat stored on your body around your waist and hips. Formula: waist measurement divided by hip measurement. Women should have a ratio of 0.8 or less; men should have a ratio of .95 or less.
Warm upTo prepare for an athletic event (whether a game or a workout session) by exercising, stretching, or practicing for a short time beforehand.
Warm up setsWarm up sets are sets you do to prepare for your working sets for a workout. For an analogy it's kind of like preheating an oven, Warm up sets help to warm up the muscles to get into the working sets of the workout.
Working SetsWorking sets are the main sets of the workout, these are done after the warm up sets. Once you are warmed up the working sets are when you really get going in the workout.
YogaA variety of Indian traditions geared toward self-discipline and the realization of unity; includes forms of exercise widely practiced in the West today that promote balance, coordination, flexibility, and meditation.

This tool helps to clear up some common myths or terminology issues as well in regards to fitness health terms, for example when you hear the word core, many times people think this is referring to the abs. That is not the case, a person’s core is made up of more than just the abdominals (abs), which you can see listed in the “core” definition in the health and fitness terminology table provided.

Is there a term you don’t know that isn’t on the table/ database we have created with health and fitness terminology? Don’t forget if you have any questions, comments, concerns or want to suggest something to us you can do so by emailing us directly at: or by using the Contact Page.

Please Note: The author of this site is not engaged in rendering professional advice or services to the individual reader. The ideas, procedures, and suggestions contained within this work are not intended as a substitute for consulting with your physician. All matters regarding your health require medical supervision. The author shall not be liable or responsible for any loss or damage allegedly arising from any information or suggestions within this blog. You, as a reader of this website, are totally and completely responsible for your own health and healthcare. Your results may vary. Testimonials and examples used are exceptional results and are not intended to guarantee, promise, represent and/or assure that anyone will achieve the same or similar results. The information provided is strictly informational material provided to further develop understanding.

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