Exercise Physiology Exam I Flashcards

Vocabulary flashcards reviewing core exercise physiology concepts from Exam I Study Guide covering Chapters 1 through 4.

Direct Calorimetry

A measurement of metabolic rate determined through the direct measurement of body heat production.

Indirect Calorimetry

A measurement of metabolic rate estimated through the measurement of oxygen consumption ($VO_2$).

Absolute $VO_2$

Oxygen consumption expressed in liters per minute ($L/min$), reflecting total oxygen used without considering body weight.

Relative $VO_2$

Oxygen consumption expressed in milliliters per kilogram per minute ($mL/kg/min$), allowing for a fair comparison between individuals of different body sizes.

MET (Metabolic Equivalent)

A unit used to express energy expenditure, where $1\text{ MET}$ is defined by a resting $VO_2$ value of $3.5\,mL/kg/min$.

Homeostasis

The maintenance of a constant and normal internal environment during resting conditions.

Steady State

A constant internal environment during exercise where a physiological variable remains constant, though not necessarily equal to resting values.

Negative Feedback Loop

A biological control system that responds by reversing the initial stimulus to restore internal stability.

Positive Feedback Loop

A biological control system where the response amplifies or increases the original stimulus.

Glycolysis

The metabolic pathway that breaks down glucose or glycogen into pyruvate or lactate.

Glycogenolysis

The enzymatic breakdown of glycogen into individual glucose molecules.

Glycogenesis

The metabolic process of synthesizing glycogen from individual glucose units.

Gluconeogenesis

The metabolic process of forming new glucose from non-carbohydrate precursors.

ATP-PC System

An anaerobic energy system that utilizes phosphocreatine to rapidly resynthesize ATP; it provides the fastest rate of ATP production but has the most limited capacity.

Krebs Cycle

A cyclic pathway in the mitochondria that oxidizes acetyl-CoA derived from carbohydrates, fats, or proteins, producing $NADH$, $FADH_2$, $ATP$, and $CO_2$.

Electron Transport Chain

A series of mitochondrial membrane complexes that transfer electrons from $NADH$ and $FADH_2$ to oxygen (the final electron acceptor) to drive ATP synthesis.

Beta Oxidation

The process of breaking down fatty acid chains into two-carbon acetyl-CoA units for entry into the Krebs cycle.

Oxygen Deficit

The lag in oxygen uptake at the onset of exercise before steady-state oxygen consumption is reached.

EPOC

Excess Post-Exercise Oxygen Consumption; the elevated oxygen uptake above resting levels that persists during recovery from exercise.

$$VO_2\text{max}$$

Maximal oxygen uptake, representing the gold-standard measure of cardiorespiratory fitness and maximal capacity to transport and utilize oxygen during exercise.

Lactate Threshold

The exercise intensity or oxygen consumption level at which blood lactate concentration begins to systematically accumulate above resting levels.

Respiratory Exchange Ratio (RER)

The ratio of carbon dioxide produced to oxygen consumed ($VCO_2 / VO_2$), used to estimate the relative contribution of carbohydrate and fat to energy metabolism.

Peripheral Fatigue

Fatigue caused by metabolic or mechanical factors operating at or beyond the neuromuscular junction, including hydrogen ion accumulation, phosphocreatine depletion, or glycogen depletion.

Central Fatigue

Fatigue originating in the central nervous system that reduces the neural drive to active muscles.