EXPH 2115: Exercise Physiology - Glossary of Important Terms

A comprehensive set of flashcards covering important vocabulary and definitions related to exercise physiology.

Exercise physiology

The study of the stress of physical activity on the body.

Acute exercise

A single bout of exercise.

Chronic exercise

Exercise training to induce adaptations.

Homeostasis during exercise

Changes in physiological variables needed to maintain critical function.

Environmental physiology

The study of the stress of environmental conditions (e.g. temperature, altitude, pressure, noise) on the body.

Bioenergetics

Study of energy-exchanging (and thus energy-generating) reactions in living things.

Energy

Capacity to do work; it takes ~100 kcal/mile.

Calories (Kcals)

A unit of energy, and the energy needed to raise 1 kg (L) of water 1 °C (equal to 1,000 calories).

Exercise

Planned, structured, and repetitive physical activity for the purpose of improving/maintaining health/function.

Physical activity

Any bodily movement beyond resting conditions.

Activities of daily living (ADLs)

Essential and routine tasks related to independent living (e.g. showering, dressing, cleaning).

Chronic disease

Includes cardiovascular disease (CAD, stroke), cancer, type II diabetes (and obesity, arthritis, dementia…).

Metabolic syndrome

Having at least 3 of 5 metabolic anomalies (hypertension, hyperglycemia, dyslipidemia, visceral adiposity).

Evolutionary mismatch theory

Perspective that living in an environment discordant to one we evolved in contributes to poorer health.

Scientific literature

The journals in which peer-reviewed research studies are published (where evidence accumulates).

Epistemology

Branch of philosophy concerned with the nature and limits of human knowledge (facts vs. opinions).

Longitudinal study design

Research involving repeated observations of certain variables in the same subjects over time.

Cross-sectional study design

Research comparing measurements taken at one time of people with different representative characteristics (e.g. age).

Experimental study design

Research that applies an intervention to subjects, ideally blinded with randomization and a control group.

Observational study design

Correlational research where researchers compare groups but don't assign or control subject behavior.

Wearable technology

General term for worn electronic devices used to track physiological or fitness-related data.

Ancient history

Era of recorded history before 500 AD (back to ~3,000 BC).

Hippocrates

Greek physician of 400 BC who established medicine as a discipline with disease as a natural phenomenon.

Galen

Activity-promoting Roman era (200 AD) doctor whose anatomy and physiology text persisted until 1500 AD.

The Renaissance

Inspired transitional period of ~15-16th century Europe with advancement in art, anatomy, astronomy.

Antonie van Leeuwenhoek

17th century Dutch microbiologist and microscopist.

The Enlightenment

17-18th century philosophical movement that precipitated evidence-based rationality and liberalism.

Antoine Lavoisier

Late 18th century French scientist who advanced understanding in many areas including O2 combustion.

A.V. Hill

Early 20th century British physiologist and muscle biochemist who helped elucidate energy metabolism.

Harvard Fatigue Lab

Foundational exercise physiology lab at Harvard University (1927-1947).

Douglas bag

Device used to collect expired air for analysis.

Ergometer

Apparatus on which work is performed (i.e. energy expended) and measured.

Philip Gollnick

Exercise physiologist who developed the muscle biopsy technique furthering understanding of muscle function.

Barbara Drinkwater

Exercise physiologist pioneering work in female physiology and female sports participation advocacy.

Katherine Switzer

First woman to officially finish the Boston Marathon (1967), advocate for female sports participation.

Joan Benoit-Samuelson

Winner of the first women's Olympic marathon in 1984.

Adenosine triphosphate (ATP)

High-energy compound formed via energy-yielding reactions as an energy source for cellular work.

Metabolism (conceptual)

Sum total of all bioenergetic reactions in the body.

Metabolism (functional)

Rate of heat production by the body, conventionally expressed in kcal/min.

Energy systems

A group of three processes (sets of reactions) used to resynthesize ATP.

Anaerobic metabolism

Reactions that resynthesize ATP without the use of O2 (e.g. phosphocreatine, glycolysis).

Substrate

Organic compound from which energy is derived via metabolism, roughly speaking phosphocreatine, carbohydrates, fat, protein.

Cytoplasm/cytosol

Intracellular aqueous space between organelles (aka sarcoplasm in muscle).

Creatine phosphate (PCr)

High-energy compound that releases energy for ATP resynthesis, part of the immediate energy system.

Glycolysis

Anaerobic/cytosolic process converting a glucose molecule into 2 pyruvate molecules, yielding 2 ATP.

Aerobic metabolism

A series of mitochondrial-based, oxygen-requiring reactions that result in resynthesis of ATP.

Mitochondrion

Organelle in which aerobic metabolism occurs (site of cellular respiration, aka powerhouse of the cell).

Direct calorimetry

Measurement of heat via use of a calorimeter as a way to assess metabolism.

Bomb calorimeter

Measurement of heat yield from total combustion of food to find energy content.

Indirect calorimetry (IC)

Measurement of respiratory gas exchange as a means to estimate heat production, thus metabolism.

VO2

Measure of O2 consumption rate (typically determined via indirect calorimetry at the level of the lungs).

VCO2

Measure of CO2 production rate (typically determined via indirect calorimetry at the level of the lungs).

Absolute VO2

Oxygen consumption expressed in L/min, indicative of aerobic metabolism (caloric energy expenditure).

Relative (mass-specific) VO2

Oxygen consumption expressed in mL/kg•min, useful when comparing individuals of different sizes.

Atmospheric CO2

While only 0.0422% of air, unabated anthropogenic contributions play a major role in the mounting greenhouse effect.

Anthropogenic

Influence of human activity on nature.

Greenhouse effect

Process where atmospheric gases trap some outwardly radiating heat thus warming the planet.

Landfill flare

The burning of methane generated from anaerobically decomposing organic matter to convert to CO2 and H2O.

Fracking flare

The burning of excess methane harvested while drilling for oil and natural gas to convert to CO2 and H2O.

Respiratory quotient (RQ)

Ratio of CO2 produced to O2 consumed during mitochondrial respiration (thus, at the tissue level).

Respiratory exchange ratio (RER)

Ratio of CO2 produced to O2 consumed as measured by indirect calorimetry (thus, VCO2/VO2 at the lung level).

Non-metabolic CO2

CO2 not from aerobic metabolism (originated from blood HCO3-), CO2 that allows RER > 1.0.

Caloric equivalent of O2

Energy yielded from the aerobic metabolism of fat and carbohydrates, expressed as ~5 kcal/L of O2.

Total daily energy expenditure (TDEE)

Sum total of all kcals burned in a day = BMR + PA + TEF.

Basal metabolic rate (BMR)

Energy required at rest under fasted and unstimulating conditions, ~1 kcal/min or 3.5 mL/kg*min.

Thermic effect of food (TEF)

Energy required to digest and absorb dietary nutrients, averages ~10% of dietary caloric intake.

Catabolism

Breakdown of complex to simpler molecules thus yielding energy.

Anabolism

Building up of simpler to more complex molecules thus requiring energy.

1st Law of Thermodynamics

Energy in a system is not created or destroyed (it is conserved and thus just changes form).

2nd Law of Thermodynamics

Total useful energy in a system dissipates = increased entropy (e.g. heat moving from hotter to colder objects).

Metabolic flexibility

The ability to rapidly shift between glucose and fatty acids as fuels during fasted and fed state transitions.

Immediate energy system

Phosphagen-based (primarily PCr) pathway, activated during explosive work to limit ATP decline.

Creatine kinase

Enzyme catalyzing ATP resynthesis from breakdown of creatine phosphate.

Myokinase (aka Adenylate kinase)

Enzyme catalyzing ATP resynthesis from 2 ADP molecules, yields AMP, part of the immediate energy system.

Adenosine monophosphate (AMP)

Product of ATP resynthesis in the adenylate kinase reaction, plays role in regulating carbohydrate metabolism.

Creatinine

Creatine breakdown waste product found in urine, blood level used as an indicator of kidney function.

Creatine loading phase

Large supplementation dose to quickly achieve maximum intramuscular levels.

Oxidation

The loss of electrons from a molecule, thus lowering the molecule's energy content.

Reduction

The gain of electrons from a molecule, thus raising the molecule's energy content.

Dehydrogenation reaction

Most biological oxidation reactions involve the removal of a hydrogen atom (e- + H+).

Redox reaction

Reaction in which one molecule loses electrons (oxidized) and another gains electrons (reduced).

Nicotinamide adenine dinucleotide

NAD+ is a cellular coenzyme that commonly carries hydrogen atoms (electrons and protons).

Flavin adenine dinucleotide

FAD is a cellular coenzyme that commonly carries hydrogen atoms (electrons and protons).

Saccharide

Sugar unit (~glucose), can be individual (monosaccharide), paired, or linked as a polymer (polysaccharide).

Polysaccharide

Glucose polymer in plants (aka digestible = starch, indigestible = fiber) and animals (aka glycogen).

Glucose

Carbohydrate (i.e. hydrated carbons), monosaccharide, common metabolic substrate.

Healthy fasting blood glucose

70-100 mg/dl.

Pyruvate

Primary 3-carbon end-product of glycolysis, two formed from each glucose molecule.

Phosphofructokinase (PFK)

Rate-limiting enzyme of glycolysis, stimulated by ADP + Pi.

Rate-limiting step

Indicates the point that determines how fast the reaction proceeds.

Lactate

Formed from the reduction of pyruvate to free up NAD+ to return to glycolysis.

Lactate dehydrogenase (LDH)

Enzyme catalyzing reduction of pyruvate to form lactate, has isoforms (LDHH, LDHM).

Decarboxylation

Reactions in which CO2 is liberated, occurs in aerobic metabolism reactions.

Acetyl-CoA

Entry molecule of the Krebs cycle and common molecule in carbohydrate, fat, and protein metabolism.

Coenzyme A (CoA)

Vitamin B5-derived cofactor required in carbohydrate & fat metabolism, functions to carry acetyl & acyl groups.

Krebs cycle

Main aerobic metabolism reactions, mitochondrial reactions oxidizing acetyl-CoA, primarily yields hydrogen atoms.

Electron transport chain (ETC)

Mitochondrial membrane assembly joining electron transfer with proton pumping and gradient generation.

Mitochondrial matrix

Most inner part of the double-membraned organelle housing aerobic metabolism.

Mitochondrial proton pump

ETC component that uses electron power to move protons up their gradient into the inner membranous space.

ATP Synthase

Enzyme on proton channel that uses energy from proton movement to phosphorylate ADP to ATP.