Exercise Physiology: Energy Expenditure, Cardiovascular Function, Respiration, and Fatigue

A practice set of 100 review flashcards covering energy expenditure, cardiovascular physiology, pulmonary function, exercise fatigue, and acute physiological responses.

According to direct calorimetry, what percentage of substrate energy is converted to ATP versus heat during metabolism?

Approximately $40\%$ of substrate energy is converted to ATP, and $60\%$ is converted to heat.

What are the primary pros and cons of using direct calorimetry to measure energy expenditure?

Pros: measures heat directly, accurate over time, and good for resting metabolic measurements. Cons: expensive, slow (cannot follow rapid changes), adds heat from exercise equipment, prone to sweat measurement errors, retains stored body heat, and is neither practical nor accurate for exercise.

What respiratory gases are measured in indirect calorimetry, and for what physiological condition is it accurate?

It measures oxygen ($\text{O}_2$) consumed and carbon dioxide ($\text{CO}_2$) produced; it is accurate only for steady-state oxidative metabolism.

How are the rate of oxygen consumption ($\dot{V}\text{O}_2$) and the rate of carbon dioxide production ($\dot{V}\text{CO}_2$) defined and calculated?

$\dot{V}\text{O}_2$ is the rate of $\text{O}_2$ consumption calculated as volume of inspired $\text{O}_2$ minus volume of expired $\text{O}_2$. $\dot{V}\text{CO}_2$ is the rate of $\text{CO}_2$ production calculated as volume of expired $\text{CO}_2$ minus volume of inspired $\text{CO}_2$.

What six gas variables are required to calculate $\dot{V}\text{O}_2$ and $\dot{V}\text{CO}_2$?

1. Volume of inspired air; 2. Volume of expired air; 3. Fraction of oxygen in inspired air; 4. Fraction of carbon dioxide in inspired air; 5. Fraction of oxygen in expired air; 6. Fraction of carbon dioxide in expired air.

On what physiological principle is the Haldane transformation based, and what does it calculate?

It is based on the constancy of nitrogen volumes ($\text{volume of inspired N}_2 = \text{volume of expired N}_2$) and allows the unknown volume of inspired air ($\dot{V}_\text{I}$) to be directly calculated from the known volume of expired air ($\dot{V}_\text{E}$).

What is the formula for calculating inspired air volume ($\dot{V}_\text{I}$) using the Haldane transformation?

$$\dot{V}_\text{I} = \frac{\dot{V}_\text{E} \times F_{\text{E}}\text{N}_2}{F_{\text{I}}\text{N}_2}$$

What is the Respiratory Exchange Ratio (RER) and what is its equation?

RER is the ratio between the rates of carbon dioxide production and oxygen usage: $\text{RER} = \frac{\dot{V}\text{CO}_2}{\dot{V}\text{O}_2}$.

What is the RER value for the complete oxidation of one molecule of glucose ($\text{C}_6\text{H}_{12}\text{O}_6$)?

The RER for glucose is $1.0$, derived from the reaction $6\,\text{O}_2 + \text{C}_6\text{H}_{12}\text{O}_6 \rightarrow 6\,\text{CO}_2 + 6\,\text{H}_2\text{O} + 32\,\text{ATP}$, where $\text{RER} = \frac{6\,\text{CO}_2}{6\,\text{O}_2} = 1.0$.

What is the RER value for the complete oxidation of one molecule of palmitic acid ($\text{C}_{16}\text{H}_{32}\text{O}_2$)?

The RER for palmitic acid is $0.70$, derived from the reaction $23\,\text{O}_2 + \text{C}_{16}\text{H}_{32}\text{O}_2 \rightarrow 16\,\text{CO}_2 + 16\,\text{H}_2\text{O} + 129\,\text{ATP}$, where $\text{RER} = \frac{16\,\text{CO}_2}{23\,\text{O}_2} = 0.70$.

What physiological limitations affect the accuracy of indirect calorimetry and RER measurements?

$P\text{CO}_2$ exhalation may not equal $P\text{CO}_2$ production; RER is inaccurate for protein oxidation; lactate accumulation drives up $\text{CO}_2$ exhalation making RER near $1.0$ inaccurate; and gluconeogenesis produces an RER $<0.70$.

Which isotopes are commonly used to study long-term energy metabolism and $\text{CO}_2$ production?

$^{13}\text{C}$ and $^2\text{H}$ (deuterium) are common, low-risk isotopes ideal for studying energy metabolism over periods of weeks.

What are the standardized resting, horizontal, and vertical energy costs of walking?

Resting: $3.5\,\text{mL\,kg}^{-1}\,\text{min}^{-1}$; horizontal: $0.1\,\text{mL\,kg}^{-1}\,\text{m}^{-1}$; and vertical: $1.8\,\text{mL\,kg}^{-1}\,\text{m}^{-1}$.

What formula determines power on a cycle ergometer?

$$\text{Power (kg/m/min)} = \text{resistance (kg)} \times \text{flywheel size (m/rev)} \times \text{cadence (rev/min)}$$

What standardized physiological conditions are required to assess Basal Metabolic Rate (BMR)?

The individual must be in the supine position in a thermoneutral environment following $8\,\text{hours}$ of sleep and $12\,\text{hours}$ of fasting.

What are the typical daily caloric expenditure ranges for Resting Metabolic Rate (RMR) and total daily metabolic activity?

RMR ranges from $1,200$ to $2,400\,\text{kcal/day}$. Normal total daily metabolic activity ranges from $1,800$ to $3,000\,\text{kcal/day}$, while competitive endurance athletes can expend up to $10,000\,\text{kcal/day}$.

What are the primary causes of the slow component of $\dot{V}\text{O}_2$ kinetics and $\dot{V}\text{O}_2$ drift?

The slow component occurs at high power outputs due to recruitment of less efficient type II muscle fibers. $\dot{V}\text{O}_2$ drift is an upward drift observed during prolonged exercise at constant low power outputs, possibly caused by ventilatory and hormonal changes.

What four physiological characteristics distinguish successful endurance athletes?

1. High $\dot{V}\text{O}_2\text{max}$; 2. High lactate threshold as a percentage of $\dot{V}\text{O}_2\text{max}$; 3. High economy of effort; 4. High percentage of type I muscle fibers.

What are the major physiological functions performed by the cardiovascular system?

Delivers $\text{O}_2$ and nutrients, removes $\text{CO}_2$ and other wastes, transports hormones and other molecules, supports temperature balance and fluid regulation, maintains acid-base balance, and regulates immune function.

What three circulatory elements make up the cardiovascular system?

1. Pump (the heart); 2. Channels or tubes (blood vessels); 3. Fluid medium (blood).

What is the sequence of blood flow through the right side of the heart?

Superior and inferior venae cavae $\rightarrow$ right atrium $\rightarrow$ tricuspid valve $\rightarrow$ right ventricle $\rightarrow$ pulmonary valve $\rightarrow$ pulmonary arteries $\rightarrow$ lungs.

What is the sequence of blood flow through the left side of the heart?

Pulmonary veins $\rightarrow$ left atrium $\rightarrow$ mitral valve $\rightarrow$ left ventricle $\rightarrow$ aortic valve $\rightarrow$ aorta.

Why does the left ventricle have the thickest myocardium, and how does it adapt to chronic exercise?

The left ventricle must pump blood throughout the entire systemic circulation to the whole body; it hypertrophies with both exercise training and disease.

How do myocardial cells differ histologically from skeletal muscle fibers?

Myocardial cells are small, short, branched, single-nucleated, contract continuously and involuntarily via calcium-induced calcium release, and are interconnected by intercalated disks.

What are the functions of desmosomes and gap junctions within cardiac intercalated disks?

Desmosomes hold adjacent cardiac cells together, while gap junctions rapidly conduct action potentials between cells.

What are the main branches of the right and left coronary arteries?

The right coronary artery divides into the marginal and posterior interventricular arteries; the left main coronary artery divides into the circumflex and anterior descending arteries.

What is the anatomical sequence of the heart's cardiac conduction system?

Sinoatrial (SA) node $\rightarrow$ atria $\rightarrow$ atrioventricular (AV) node $\rightarrow$ AV bundle (bundle of His) $\rightarrow$ right and left bundle branches $\rightarrow$ Purkinje fibers.

What makes the sinoatrial (SA) node the primary pacemaker, and what is the intrinsic heart rate?

Its cells in the upper posterior right atrial wall are especially leaky to $\text{Na}^+$, giving it spontaneous rhythmicity with an intrinsic rate of approximately $100\,\text{beats/min}$.

What is the physiological role of the conduction delay at the atrioventricular (AV) node?

The delay allows the right and left atria to contract and empty their blood into the ventricles before the ventricles contract.

How does the parasympathetic nervous system modulate heart function via the vagus nerve?

The vagus nerve (cranial nerve X) releases acetylcholine to hyperpolarize cells, decreasing heart rate and force of contraction below the intrinsic rate.

How does the sympathetic nervous system alter heart activity, and what is the maximal possible heart rate?

Sympathetic fibers release norepinephrine to facilitate depolarization, increasing heart rate and contraction force, with a maximal possible heart rate of $250\,\text{beats/min}$.

What cardiac electrical events are represented by the P wave, QRS complex, and T wave on an electrocardiogram (ECG)?

P wave: atrial depolarization; QRS complex: ventricular depolarization; T wave: ventricular repolarization.

What mechanical events occur during ventricular systole and what produces the first heart sound ('lub')?

Ventricular pressure rises, closing the atrioventricular valves (sound 1, 'lub'), semilunar valves open, blood is ejected, and the remaining blood volume is end-systolic volume (ESV).

What mechanical events occur during ventricular diastole and what produces the second heart sound ('dub')?

Ventricular pressure drops, semilunar valves close (sound 2, 'dub'), atrioventricular valves open, and ventricles fill ($70\%$ passively, $30\%$ by atrial contraction) to end-diastolic volume (EDV).

What is stroke volume (SV), what is its formula, and what is a typical resting calculation?

SV is the volume of blood pumped in one heartbeat: $\text{SV} = \text{EDV} - \text{ESV}$. For example, $100\,\text{mL} - 40\,\text{mL} = 60\,\text{mL}$.

What is ejection fraction (EF), how is it calculated, and what is its clinical significance?

EF is the percentage of EDV pumped per beat: $\text{EF} = \frac{\text{SV}}{\text{EDV}}$. (e.g., $60\,\text{mL} / 100\,\text{mL} = 60\%$); it serves as a clinical index of heart contractile function.

What is cardiac output ($\dot{Q}$), how is it calculated, and what are typical resting values?

$\dot{Q}$ is the total volume of blood pumped per minute: $\dot{Q} = \text{HR} \times \text{SV}$. Resting values typically range from $4.2$ to $5.6\,\text{L/min}$ (averaging around $5\,\text{L/min}$).

What is torsional contraction of the heart during exercise?

During systole, the heart twists gradually like a spring storing potential energy; during diastole, abrupt untwisting facilitates dynamic relaxation to enhance left ventricular filling.

How is mean arterial pressure (MAP) calculated from resting blood pressure values?

$$\text{MAP} \approx \frac{2}{3}\,\text{DBP} + \frac{1}{3}\,\text{SBP}$$

What mathematical relationship defines vascular resistance ($R$), and which vascular factor has the greatest influence?

$R = \frac{L}{r^4}$; the vessel radius ($r$) is the most critical factor because resistance is inversely proportional to radius to the fourth power.

Why are arterioles designated as the primary resistance vessels of the systemic circulation?

Arterioles control systemic resistance through potent vasoconstriction and vasodilation and are responsible for $70\%$ to $80\%$ of the total pressure drop from the left ventricle to the right atrium.

How does blood flow distribution to skeletal muscle and splanchnic organs change between rest and heavy exercise?

At rest ($\dot{Q} = 5\,\text{L/min}$), skeletal muscle receives $\sim 20\%$ and viscera receive $50\%$. During heavy exercise ($\dot{Q} = 25\,\text{L/min}$), exercising muscle receives $80\%$ of $\dot{Q}$ via vasodilation, while flow to liver and kidneys decreases via vasoconstriction.

What three intrinsic mechanisms regulate local tissue blood flow in arterioles?

1. Metabolic mechanisms (buildup of local metabolic by-products); 2. Endothelial mechanisms (substances like nitric oxide, prostaglandins, and EDHF); 3. Myogenic mechanisms (vascular responses to local pressure changes).

What is functional sympatholysis in exercising skeletal muscle?

Inhibition of sympathetic vasoconstriction caused by reduced vascular responsiveness to $\alpha$-adrenergic receptor activation, allowing exercising muscle to overcome vasoconstriction and increase blood flow.

What three physiological mechanisms assist venous return to the heart in the upright posture?

1. One-way venous valves; 2. The skeletal muscle pump; 3. The respiratory pump.

What are the proportions of plasma versus formed elements in whole blood, and what is hematocrit?

Whole blood consists of $55\%$ to $60\%$ plasma and $40\%$ to $45\%$ formed elements ($99\%$ of which are red blood cells); hematocrit is the percentage of total blood volume composed of formed elements.

How much oxygen does each gram of hemoglobin bind, and what is the oxygen-carrying capacity of whole blood?

Each gram of hemoglobin binds $1.34\,\text{mL}\;\text{O}_2$, yielding an oxygen-carrying capacity of approximately $20\,\text{mL}\;\text{O}_2$ per $100\,\text{mL}$ of whole blood.

What is blood viscosity, and what happens when hematocrit increases without an increase in plasma volume?

Viscosity is blood thickness primarily due to red blood cells; when hematocrit rises without expanding plasma volume, blood viscosity increases, which can compromise blood flow and oxygen transport.

What are the four primary processes of the respiratory system?

1. Pulmonary ventilation (external respiration); 2. Pulmonary diffusion (external respiration); 3. Transport of gases via the blood; 4. Capillary diffusion (internal respiration).

What anatomical pathway does air travel from the atmosphere to the alveoli?

Nose/mouth $\rightarrow$ nasal conchae $\rightarrow$ pharynx $\rightarrow$ larynx $\rightarrow$ trachea $\rightarrow$ bronchial tree $\rightarrow$ alveoli.

How does Boyle's law explain the movement of air into the lungs during inspiration?

Boyle's law states that pressure and volume are inversely proportional at constant temperature; as inspiratory muscles expand lung volume, intrapulmonary pressure drops below atmospheric pressure, drawing air passively in.

What accessory muscles are engaged during forced inspiration and forced expiration?

Forced inspiration engages the scalenes, sternocleidomastoid, and pectorals. Forced expiration engages the internal intercostals, latissimus dorsi, quadratus lumborum, and abdominal muscles.

How does the respiratory pump enhance venous return to the right atrium?

Pressure changes during breathing rhythmically squeeze abdominal veins while lowering intrathoracic pressure, producing a milking action that promotes right atrial filling.

What percentage of total body oxygen consumption is utilized by respiratory muscles at rest compared to intense exercise?

At rest, the work of breathing consumes $<5\%$ of resting $\dot{V}\text{O}_2$, but during intense exercise, it can consume up to $30\%$ of $\dot{V}\text{O}_2$.

How do mean arterial pressure and resistance in the pulmonary circulation compare to systemic circulation?

Pulmonary circulation has a low MAP of $15\,\text{mmHg}$ (vs systemic aortic MAP of $95\,\text{mmHg}$) with left atrial pressure of $5\,\text{mmHg}$, producing a small gradient ($15\,\text{mmHg}$ to $5\,\text{mmHg}$) with much lower resistance due to thinner vessel walls.

What structures comprise the respiratory membrane, and what are its surface area and thickness dimensions?

Composed of the alveolar wall, capillary wall, and their basement membranes; spans $300\,\text{million}$ alveoli with a diffusion barrier thickness of only $0.5$ to $4\,\mu\text{m}$.

According to Dalton's law, what are the percentages and partial pressures of $\text{N}_2$, $\text{O}_2$, and $\text{CO}_2$ at sea level ($760\,\text{mmHg}$)?

$\text{N}_2 = 79.04\%$ ($600.7\,\text{mmHg}$); $\text{O}_2 = 20.93\%$ ($159.1\,\text{mmHg}$); $\text{CO}_2 = 0.03\%$ ($0.2\,\text{mmHg}$).

What does Henry's law state regarding gas dissolution in liquids?

Gases dissolve in liquids in proportion to their partial pressure, solubility in the specific fluid medium, and temperature.

What is the resting partial pressure gradient for oxygen across the respiratory membrane?

Alveolar $P\text{O}_2$ is $105\,\text{mmHg}$ and pulmonary artery $P\text{O}_2$ is $40\,\text{mmHg}$, producing a $65\,\text{mmHg}$ diffusion gradient across the membrane resulting in pulmonary vein $P\text{O}_2 \sim 100\,\text{mmHg}$.

What factors determine the rate of gas diffusion according to Fick's law?

The rate of diffusion is directly proportional to tissue surface area and partial pressure gas gradient, and inversely proportional to tissue thickness.

Why does carbon dioxide diffuse across the respiratory membrane rapidly despite a small pressure gradient of only $6\,\text{mmHg}$?

Because the diffusion constant of carbon dioxide is $20$ times greater than that of oxygen, permitting rapid diffusion despite the small gradient ($46\,\text{mmHg}$ to $40\,\text{mmHg}$).

What is resting oxygen diffusion capacity and how does it change during maximal exercise?

At rest, it is $21\,\text{mL}\;\text{O}_2/\text{min}/\text{mmHg}$ of gradient ($231\,\text{mL}\;\text{O}_2/\text{min}$ for an $11\,\text{mmHg}$ gradient); during maximal exercise, it increases by three times the resting rate.

Why is pulmonary diffusion capacity limited at rest, and how does exercise alter lung perfusion?

At rest, blood flow perfuses only the bottom $1/3$ of the lung; during exercise, elevated systemic blood pressure opens perfusion in the top $2/3$, allowing gas exchange over the full lung surface area.

In what two forms is oxygen transported in the blood, and in what proportions?

Greater than $98\%$ is bound to hemoglobin in red blood cells (oxyhemoglobin), and less than $2\%$ is dissolved directly in plasma.

What is the Bohr effect and what causes it during exercise?

Increased blood acidity (lower pH) shifts the oxygen-hemoglobin dissociation curve to the right, causing hemoglobin to unload more oxygen at exercising muscle tissues.

How does elevated blood temperature affect the oxygen-hemoglobin dissociation curve?

Higher temperature shifts the dissociation curve to the right, promoting greater tissue oxygen unloading during exercise.

What are the three forms of carbon dioxide transport in blood and their relative proportions?

1. As bicarbonate ions ($60\%$ to $70\%$); 2. Bound to hemoglobin as carbaminohemoglobin ($20\%$ to $33\%$); 3. Dissolved in blood plasma ($7\%$ to $10\%$).

What chemical reaction forms bicarbonate in red blood cells, and what enzyme catalyzes it?

$\text{CO}_2 + \text{H}_2\text{O} \leftrightarrow \text{H}_2\text{CO}_3 \leftrightarrow \text{HCO}_3^- + \text{H}^+$, catalyzed by carbonic anhydrase.

How does hemoglobin oxygenation state affect its affinity for binding carbon dioxide?

Deoxyhemoglobin binds carbon dioxide much more easily than oxyhemoglobin does, allowing venous blood to carry more $\text{CO}_2$.

What is the arterial-venous oxygen difference ((a-v)O2 difference) at rest versus during heavy exercise?

Arterial $\text{O}_2$ content is $20\,\text{mL}\;\text{O}_2/100\,\text{mL}$. Mixed venous $\text{O}_2$ is $4$ to $5\,\text{mL}\;\text{O}_2/100\,\text{mL}$ blood at rest, and extraction increases during heavy exercise so the $(a\text{-}\bar{v})\text{O}_2$ difference expands to $15$ to $16\,\text{mL}\;\text{O}_2/100\,\text{mL}$ blood.

How does the oxygen-myoglobin dissociation curve differ from the oxygen-hemoglobin curve?

Myoglobin has a higher affinity for $\text{O}_2$ with a very steep curve between $0$ and $20\,\text{mmHg}$, loading $\text{O}_2$ at $20\,\text{mmHg}$ and releasing it only at very low tissue pressures ($1$ to $2\,\text{mmHg}$).

What chemical stimulus directly activates central chemoreceptors in the brain stem to regulate breathing?

An accumulation of hydrogen ions ($\text{H}^+$) in the cerebrospinal fluid.

What is the Hering-Breuer reflex and what initiates it?

A reflex initiated by stretch receptors in the pleurae, bronchioles, and alveoli that reduces breathing depth when tissues are excessively stretched.

What are the two formal definitions of fatigue presented in the notes?

1. Decrements in muscular performance with continued effort, accompanied by sensations of tiredness; 2. Inability to maintain required power output to continue muscular work at a given intensity.

What fundamental characteristic distinguishes fatigue from muscle weakness or muscle damage?

Fatigue is reversible by rest.

What four major synergistic mechanisms contribute to muscle fatigue?

1. Decreased rate of energy delivery; 2. Accumulation of metabolic by-products; 3. Failure of muscle contractile mechanism; 4. Altered neural control of muscle contraction.

Why does phosphocreatine (PCr) depletion coincide with muscular fatigue during high-intensity exercise?

PCr is depleted more quickly than total ATP; its depletion limits the immediate resynthesis of ATP needed to maintain muscular work.

In what order are muscle fiber types recruited and depleted of glycogen as exercise intensity increases?

Type I fibers are recruited and depleted first (light/moderate intensity), followed by Type IIa fibers (moderate/high intensity), and Type IIx fibers last (maximal intensity).

How do intracellular muscle pH levels of $<6.9$ and $6.4$ specifically impair energy metabolism?

At pH $<6.9$, glycolytic enzymes are inhibited and ATP synthesis slows; at pH $= 6.4$, further glycogen breakdown is prevented, causing a rapid decrease in ATP.

At what ambient temperatures is time to exhaustion longest and shortest during exercise?

Time to exhaustion is longest at an ambient temperature of $11^\circ\text{C}$ and shortest at $31^\circ\text{C}$.

What is critical power and what metabolic system sustains it?

Critical power is the tolerable duration of high-intensity exercise representing the highest metabolic rate that can be maintained entirely by oxidative metabolism.

What physiological mechanisms cause acute muscle soreness during and immediately after exercise?

Accumulation of metabolic by-products ($\text{H}^+$) and tissue edema resulting from plasma fluid shifting into the interstitial space.

What type of muscle contraction is the primary cause of Delayed-Onset Muscle Soreness (DOMS)?

Eccentric muscle contractions (e.g., downhill running causes more pain than level running).

What structural damage occurs within sarcomeres after eccentric exercise, and what blood marker reflects it?

Structural damage to sarcomere Z-disks occurs, accompanied by a $2$ to $10$-fold increase in muscle enzymes in the blood.

What are the five sequential stages in the development of DOMS?

1. High tension causes structural damage to muscle and cell membrane; 2. Disturbed calcium homeostasis inhibits cellular respiration and activates Z-disk degrading enzymes; 3. Circulating neutrophils increase; 4. Macrophages accumulate histamine, kinins, and $\text{K}^+$, stimulating pain nerves; 5. Fluid and electrolytes shift into the area, creating edema.

What three factors cause the loss of muscle strength following DOMS, and which is apparently most important?

1. Physical disruption of muscle; 2. Failure in excitation-contraction coupling (apparently the most important factor); 3. Loss of contractile protein.

What are the two prevailing theories for exercise-associated muscle cramps?

The neuromuscular control theory (altered control with hyperexcitable motor neurons and spontaneous peripheral motor nerve discharges) and the electrolyte depletion theory (heat cramps associated with large sweat losses of sodium and chloride).

What causes the anticipatory heart rate response immediately before exercise begins?

Decreased vagal tone and increased sympathetic stimulation releasing norepinephrine and epinephrine from central command.

What formulas estimate maximal heart rate in the general population and in older adults?

General: $\text{HR}_{\max} = 220 - \text{age}$; Older adults: $\text{HR}_{\max} = 208 - (0.7 \times \text{age})$ or $\text{HR}_{\max} = 211 - (0.64 \times \text{age})$.

What is steady-state heart rate and how long does it take to adjust to a new workload?

The plateau of optimal HR meeting circulatory demands at a given submaximal intensity; adjusting to a new intensity takes $2$ to $3\,\text{minutes}$.

At what exercise intensity does stroke volume plateau in most individuals?

Stroke volume increases with intensity and plateaus at $40\%$ to $60\%\,\dot{V}\text{O}_2\text{max}$, remaining plateaued through exhaustion (except possibly in elite endurance athletes).

How does the Frank-Starling mechanism increase stroke volume during exercise?

Increased venous return increases end-diastolic ventricular stretch (preload), which directly increases the strength of myocardial contraction.

How does sympathetic stimulation increase stroke volume independently of end-diastolic volume?

Increased sympathetic release of norepinephrine and epinephrine increases inherent ventricle contractility, elevating ejection fraction independently of EDV.

What is the Fick principle equation for tissue oxygen consumption?

$$\dot{V}\text{O}_2 = \dot{Q} \times (a\text{-}\bar{v})\text{O}_2\text{ difference} = \text{HR} \times \text{SV} \times (a\text{-}\bar{v})\text{O}_2\text{ difference}$$

How do systolic and diastolic blood pressure typically respond to progressive endurance exercise?

Systolic BP increases in direct proportion to exercise intensity, while diastolic BP remains unchanged or decreases slightly at maximal exercise.

What is rate-pressure product and what physiological parameter does it estimate?

Calculated as $\text{Rate-Pressure Product} = \text{HR} \times \text{SBP}$; it is directly related to myocardial oxygen uptake and coronary blood flow.

How high can arterial blood pressure spike during heavy resistance exercise with the Valsalva maneuver?

Blood pressure can spike up to $480/350\,\text{mmHg}$.

What is cardiovascular drift and what causes it during prolonged steady-state exercise?

A gradual downward drift in stroke volume (caused by dehydration, decreased plasma volume from sweating, and blood pooling in skin) coupled with an upward drift in heart rate to maintain cardiac output.

What is the ventilatory threshold and how does it relate to the ventilatory equivalent for oxygen ($\dot{V}_\text{E}/\dot{V}\text{O}_2$)?

The ventilatory threshold is the point where liters of air breathed disproportionately exceeds liters of $\text{O}_2$ consumed, matching the lactate threshold and excess $\text{CO}_2$ accumulation from bicarbonate buffering.

What mechanisms drive postexercise hypotension following aerobic versus resistance exercise?

Aerobic exercise causes postexercise hypotension via peripheral vasodilation mediated by histamine; resistance exercise causes it via decreased cardiac output.