Acute Responses to Exercise & Chronic Adaptations to Training

Comprehensive vocabulary flashcards covering the acute cardiovascular, respiratory, and muscular responses to exercise, as well as the chronic physiological adaptations that occur following long-term training.

Acute Response to Exercise

An immediate physiological response occurring at the onset of exercise to cope with the body's demands, which returns to pre-exercise baseline levels following an exercise bout.

Chronic Adaptation to Training

A long-term structural or functional change to the body's systems developed as a result of sustained training over a minimum duration of $6+\text{ weeks}$.

Maximum Heart Rate (MHR)

The highest number of heartbeats per minute an individual can achieve, calculated using the formula: $\text{MHR} = 220 - \text{Age}$.

Aerobic Zone

The exercise intensity training zone spanning $70\text{--}84\%$ of an individual's maximum heart rate, where ATP energy production occurs with the presence of oxygen.

Anaerobic Zone

The high-intensity exercise training zone spanning $85\text{--}100\%$ of maximum heart rate, where ATP is produced without sufficient oxygen, leading to fatigue.

Oxygen Deficit

The shortfall between the oxygen required by working muscles and the actual oxygen taken in and consumed at the start of exercise, during which ATP must be produced anaerobically.

Steady State

The physiological phase during aerobic exercise where oxygen supply equals oxygen demand, characterized by a leveling off of oxygen consumption and a consistent heart rate.

Excess Post-Exercise Oxygen Consumption (EPOC)

The volume of oxygen consumed above resting levels after exercise cessation, used to aid in the removal of accumulated $H^+$ ions and replenish creatine phosphate stores.

Anticipatory Response

A slight preliminary rise in heart rate and pulmonary ventilation occurring immediately prior to physical exertion as the body prepares for exercise.

Heart Rate (HR)

The frequency of myocardial contractions measured in beats per minute ($\text{BPM}$), which increases acutely during exercise to elevate blood and oxygen delivery.

Stroke Volume (SV)

The volume of blood ejected from the left ventricle of the heart into the aorta during each myocardial contraction, measured in $\text{mL/beat}$.

Cardiac Output (Q)

The total volume of blood pumped out by the heart per minute, expressed in $\text{L/min}$ and calculated by the equation: $Q = \text{HR} \times \text{SV}$.

Pulmonary Ventilation (V)

The total volume of air inhaled and exhaled per minute, measured in $\text{L/min}$ and calculated using the formula: $V = \text{RR} \times \text{TV}$.

Tidal Volume (TV)

The volume of air inspired or expired in a single respiratory cycle, measured in $\text{mL/breath}$.

Respiratory Rate (RR)

The total number of respiratory cycles (breaths) completed per minute, which increases acutely during exercise to enhance gas exchange.

Vasodilation

The widening of the internal diameter of blood vessels, directed toward active skeletal muscles and the skin during exercise to increase localized blood and oxygen delivery.

Vasoconstriction

The narrowing of blood vessels supplying non-essential organs (such as the kidneys, liver, stomach, and intestines) to redirect blood flow to active muscles during exercise.

Medulla

The structure located in the brainstem responsible for detecting physiological shifts and regulating acute cardiovascular adjustments during exercise.

Cardiac Hypertrophy

A chronic training adaptation characterized by the enlargement and thickening of the left ventricular muscular wall, enabling more forceful contractions and greater stroke volume.

Metabolic By-Products

Substances such as lactate and hydrogen ions ($H^+$) that accumulate inside active muscles when energy is produced via anaerobic pathways at intensities of $85\%+$ of maximum heart rate.

Fuel Depletion

The progressive exhaustion of internal food fuel stores—primarily carbohydrates and fats—used by muscle tissues to synthesize ATP during ongoing physical activity.

Motor Unit Recruitment

An acute muscular response where an increased number of motor units and muscle fibers are activated simultaneously to generate greater muscular force during exercise.

$$\text{VO}_2$$

The absolute volume of oxygen taken up, transported, and utilized by the body's tissues per minute during rest or physical exertion.

$$\text{VO}_2\text{ max}$$

The maximum volume of oxygen that the body can take in (respiratory), transport (cardiovascular), and use (muscular) per minute, expressed relative to mass in $\text{mL/kg/min}$.

Mitochondria

The aerobic powerhouse organelles of muscle cells responsible for producing ATP, which increase in both size and total number as a chronic adaptation to aerobic training.

Decreased Resting Heart Rate

A chronic adaptation where resting heart rate falls due to increased stroke volume and cardiac efficiency, delivering required oxygen with fewer ventricular contractions.

Decreased Resting Respiratory Rate

A chronic respiratory adaptation where resting breaths per minute decline because improved lung efficiency allows more $O_2$ and $CO_2$ to be exchanged per individual breath.