ACSM-EP Pathophysiology 3 — Questions and Answers
Question 1: Which pathophysiological change in osteoporosis most directly increases fracture risk during exercise?
- Increased osteoclast activity reducing bone mineral density below fracture threshold (Correct answer)
- Decreased periosteal diameter reducing bone cross-sectional area
- Impaired collagen synthesis reducing bone flexibility
- Calcification of joint cartilage increasing stress on subchondral bone
Correct answer: Increased osteoclast activity reducing bone mineral density below fracture threshold
Excessive osteoclast resorption relative to osteoblast formation reduces bone mineral density to levels where normal mechanical loads exceed bone strength.
Question 2: A client with rheumatoid arthritis (RA) experiences morning stiffness lasting over one hour. This symptom results from which pathological process?
- Cartilage wear causing mechanical joint locking
- Synovial inflammation and pannus formation causing joint swelling overnight (Correct answer)
- Muscle spasm from guarding inflamed joints during sleep
- Calcification of the joint capsule restricting range of motion
Correct answer: Synovial inflammation and pannus formation causing joint swelling overnight
RA-related synovitis causes synovial fluid accumulation and pannus formation; prolonged inactivity during sleep allows inflammatory exudate to thicken, causing stiffness that mobilizes with movement.
Question 3: Which pulmonary response to exercise is most abnormal in a patient with pulmonary hypertension?
- Failure of pulmonary vascular resistance to decrease with increased cardiac output (Correct answer)
- Excessive bronchodilation reducing dead space ventilation
- Decreased arterial oxygen saturation due to diffusion limitation at rest
- Impaired tidal volume expansion from reduced chest wall compliance
Correct answer: Failure of pulmonary vascular resistance to decrease with increased cardiac output
Normally, pulmonary vascular resistance falls during exercise as vessels recruit and dilate; in pulmonary hypertension, vascular remodeling prevents this response, increasing right ventricular afterload.
Question 4: In a patient with autonomic neuropathy from long-standing diabetes, what exercise response would the EP expect?
- Exaggerated heart rate increase due to sympathetic overactivation
- Blunted heart rate response and orthostatic hypotension risk (Correct answer)
- Paradoxical decrease in blood pressure during exercise
- Enhanced sweating impairing thermoregulation during heat exposure
Correct answer: Blunted heart rate response and orthostatic hypotension risk
Autonomic neuropathy damages sympathetic and parasympathetic fibers, impairing heart rate regulation and blood pressure response to positional changes.
Question 5: Which mechanism explains why patients with anemia have reduced exercise capacity?
- Decreased plasma volume reducing preload and stroke volume
- Reduced oxygen-carrying capacity lowering maximal oxygen delivery to muscles (Correct answer)
- Impaired 2,3-DPG production shifting the oxyhemoglobin curve left
- Increased blood viscosity limiting muscle perfusion
Correct answer: Reduced oxygen-carrying capacity lowering maximal oxygen delivery to muscles
Hemoglobin concentration directly determines oxygen-carrying capacity; low hemoglobin reduces the amount of O2 delivered per unit of cardiac output, limiting VO2max.
Question 6: Exercise-induced bronchospasm (EIB) is triggered primarily by which mechanism?
- Increased airway pressure from forced expiration damaging bronchial epithelium
- Airway cooling and drying during high ventilation causing mast cell degranulation (Correct answer)
- Lactic acid-induced bronchial smooth muscle contraction
- Parasympathetic dominance reducing bronchial diameter during recovery
Correct answer: Airway cooling and drying during high ventilation causing mast cell degranulation
Rapid breathing of cool, dry air during exercise dehydrates and cools bronchial mucosa, triggering mast cell release of histamine and leukotrienes causing bronchoconstriction.
Question 7: In heart failure with preserved ejection fraction (HFpEF), exercise intolerance is primarily caused by which mechanism?
- Systolic dysfunction preventing adequate cardiac output increase
- Impaired left ventricular relaxation limiting diastolic filling at higher heart rates (Correct answer)
- Severe mitral regurgitation reducing forward stroke volume
- Right ventricular failure causing systemic venous congestion
Correct answer: Impaired left ventricular relaxation limiting diastolic filling at higher heart rates
In HFpEF the ventricle is stiff; as heart rate rises during exercise, diastolic filling time shortens but the stiff ventricle cannot fill quickly, limiting stroke volume and cardiac output.
ACSM-EP Pathophysiology 3
Which pathophysiological change in osteoporosis most directly increases fracture risk during exercise?