Clinical Exercise Physiology: Chronic Heart Failure, CAD/PAD, Aging, and Exercise Prescription

Comprehensive practice flashcards covering pathophysiology, functional classifications, diagnostic tests, exercise prescriptions, and aging considerations for chronic heart failure, CAD, PAD, and general physical fitness.

Chronic Heart Failure (CHF)

The pathophysiological state in which the heart is unable to pump blood at a rate commensurate with the requirements of metabolizing tissues, failing to keep up with bodily demand.

Systolic Dysfunction

A form of heart failure characterized by the inability of cardiac myofibrils to contract against a load, resulting in reduced ejection fraction and impaired blood ejection.

Diastolic Dysfunction

A form of heart failure caused by increased stiffness or decreased compliance of the ventricle, preventing proper ventricular expansion and filling while preserving ejection fraction.

Peak $\dot{V}O_2$ Mortality Thresholds in CHF

Prognostic cutoffs during exercise testing where a peak $\dot{V}O_2 > 17\,\text{mL}\cdot\text{kg}^{-1}\cdot\text{min}^{-1}$ corresponds to a $20\%$ risk of death within 3 years, whereas a value $< 14\,\text{mL}\cdot\text{kg}^{-1}\cdot\text{min}^{-1}$ increases 3-year mortality risk to $50\%$.

New York Heart Association (NYHA) Classification

A functional classification system for heart failure based on symptom limitation: Class I (mild, no activity limitations), Class II (mild, slight limitation with ordinary activity), Class III (moderate, marked limitation with less than ordinary activity), and Class IV (severe, symptoms present at rest and inability to perform any physical activity without discomfort).

AHA/ACC Heart Failure Stages

A staging schema incorporating cardiac anatomy and symptoms: Stage A (high risk without structural disease or symptoms), Stage B (structural heart disease without symptoms), Stage C (structural heart disease with prior or current symptoms), and Stage D (refractory heart failure requiring specialized interventions).

Myocardial Infarction (MI)

The cellular damage or death of cardiomyocytes caused by a substantial decrease or complete interruption of blood flow through a coronary artery, depriving downstream tissues of oxygen.

Atherosclerosis

A vascular disease characterized by the thickening, calcification, and loss of elasticity of artery walls along with the progressive buildup of fibrofatty plaque on the inner lumen.

Ejection Fraction (EF)

The percentage of blood volume in the left ventricle that is ejected with each contraction, calculated as $EF = \left(\frac{SV}{EDV}\right) \times 100$.

ST-Segment Elevation

An electrocardiographic deviation indicating acute transmural myocardial ischemia or infarction resulting from severe coronary artery occlusion.

Symptom-Limited Exercise Testing

A graded exercise testing protocol terminated upon the onset of signs or symptoms such as angina, ST-segment depression $\ge 2\,\text{mm}$, hypotension, ventricular arrhythmias, or fatigue; it induces an ischemic response nearly twice as often as submaximal testing.

Phase 1 Cardiac Rehabilitation

The inpatient cardiac rehabilitation phase initiated before hospital discharge to counteract the negative effects of bed rest (such as the loss of $\dot{V}O_2\text{max}$ at $1\%$ per day) using orthostatic workloads, early ambulation on the second or third day, and range of motion exercises.

Phase 2 Cardiac Rehabilitation

The early outpatient rehabilitation phase occurring between 2 and 12 weeks after discharge, tailored using exercise-stress testing to evaluate functional capacity, ischemic symptoms, blood pressure, heart rate, and ratings of perceived exertion.

Phase 3 Cardiac Rehabilitation

The long-term, home- or community-based maintenance phase of cardiac rehab aimed at lifelong risk factor reduction and fitness maintenance, typically inducing a $10\%$ to $30\%$ increase in $\dot{V}O_2\text{max}$ after 8 weeks.

Heart Rate Reserve (HRR)

The difference between maximal heart rate and resting heart rate used to calculate target training intensity using the formula: $HRR = ((HR_{\max} - RHR) \times \text{Training } \%) + RHR$.

Peripheral Arterial Disease (PAD)

A condition caused by atherosclerotic plaque buildup and luminal narrowing in non-coronary systemic arteries—principally supplying the lower extremities—which impairs blood flow and limb functional capacity.

Intermittent Claudication

Reversible muscle pain, ache, fatigue, or cramping occurring in the lower extremities during physical activity, induced by exercise-related skeletal muscle ischemia and relieved by rest.

Ankle-Brachial Index (ABI)

The diagnostic ratio of the higher systolic blood pressure at the ankle (posterior tibial or dorsalis pedis) to the higher brachial systolic blood pressure, where a resting ratio $\le 0.90$ establishes the diagnosis of PAD.

Claudication Pain Scale

A 5-point subjective grading scale for ischemic lower-extremity pain ranging from 0 (no pain), 1 (definite initial or modest discomfort), 2 (moderate pain allowing diverted attention), 3 (intense pain from which attention cannot be diverted), to 4 (excruciating and unbearable pain).

Fontaine Classification

A four-stage clinical grading scheme for PAD: Stage 1 (asymptomatic), Stage 2a (claudication onset at walking distance $> 200\,\text{m}$), Stage 2b (claudication onset at $< 200\,\text{m}$), Stage 3 (ischemic rest pain), and Stage 4 (gangrene or tissue loss).

Old-Age Support Ratio

A demographic metric denoting the number of working-age individuals (aged 15 to 64 years) per older individual (aged 65 years or over), documented globally at 12:1 in 1950, 8:1 in 2013, and projected to decline to 4:1 by 2050.

Sarcopenia

The progressive, age-related decline of skeletal muscle mass and strength, prominently driven by atrophy and loss of Type II muscle fibers between the third and sixth decades of life.

SARC-F Screen

A 5-item clinical screening questionnaire evaluating sarcopenia based on difficulty in Strength (lifting 10 lb), Assistance in walking across a room, Rise from a chair/bed, Climbing 10 stairs, and frequency of Falls in the past year.

Age-Related Lung Compliance Change

The increase in the ease with which pulmonary tissue stretches as a result of aging, which pairs with decreased elastic recoil and alveolar surface loss to trap air and increase the work of breathing.

Endothelial Dysfunction

The loss of the vascular endothelium's capacity to induce normal vasodilation in response to physiological stimuli or shear stress, commonly reduced by up to $50\%$ with aging but reversible via endurance exercise.

Senior Fitness Test

A comprehensive 7-item battery assessing functional independence in older adults through the 30-second chair stand, 30-second arm curls, 8-foot up-and-go, 6-minute walk, 2-minute step test, sit-and-reach, and back scratch.

Physical Activity vs. Physical Fitness

Physical activity is any muscular contraction that results in caloric energy expenditure proportional to work, whereas physical fitness denotes the set of attributes allowing one to perform daily tasks with vigor and meet unforeseen emergencies.

Dose-Response Relationship

The mathematical association describing the magnitude of biological effect or adaptation (response) produced as a function of the exposure level, duration, and frequency of an administered drug or exercise regimen (dose).

Absolute vs. Relative Intensity

Absolute intensity expresses energy expenditure or work rate independently of personal physiological limits (such as Watts, METs, or $\dot{V}O_2$), whereas relative intensity expresses effort relative to an individual's maximum capacity (such as $\%HR_{\max}$, $\%HRR$, or $\%\dot{V}O_2\max$).

Progressive Overload Principle

The training principle stating that exercising tissues must be subjected to a workload greater than habitual levels; when combined with sufficient recovery, it stimulates positive training adaptations and elevates baseline fitness.

Interval Training

An exercise modality consisting of repeated work bouts separated by structured rest periods; intervals exceeding $60\,\text{s}$ target aerobic ATP production, while shorter intervals ($5\text{--}10\,\text{s}$ or $20\text{--}60\,\text{s}$) stress phosphagen or glycolytic pathways.

Long, Slow Distance (LSD) Training

A continuous aerobic training regimen performed at low to moderate intensities across distances greater than competition lengths, intended to condition cardiopulmonary function.

Isokinetic Contraction

A dynamic muscle action performed against accommodative resistance where the velocity of movement remains constant throughout the entire range of motion, typically evaluated using specialized dynamometers.