ACSM-EP Pathophysiology — Questions and Answers
Question 1: Which pathophysiologic feature best characterizes type 2 diabetes mellitus?
- Autoimmune destruction of pancreatic beta cells causing absolute insulin deficiency
- Insulin resistance in skeletal muscle, liver, and adipose tissue with progressively inadequate beta-cell insulin secretion (Correct answer)
- Excess glucagon secretion from a pancreatic tumor
- Impaired renal glucose reabsorption with normal insulin action
Correct answer: Insulin resistance in skeletal muscle, liver, and adipose tissue with progressively inadequate beta-cell insulin secretion
Type 2 diabetes involves insulin resistance combined with relative, progressive insulin secretory failure.
In type 2 diabetes, target tissues respond poorly to insulin, and the beta cells eventually cannot compensate, causing chronic hyperglycemia. Autoimmune beta-cell destruction describes type 1 diabetes. Exercise helps type 2 diabetes because muscle contraction increases GLUT4 translocation and glucose uptake independent of insulin, and regular training improves insulin sensitivity for 24-72 hours after a session. This is why ACSM recommends aerobic exercise at least 3 days per week with no more than 2 consecutive days without activity.
Question 2: During a graded exercise test, a client develops chest discomfort and 2 mm of horizontal ST-segment depression. This finding most likely reflects:
- Myocardial ischemia from oxygen demand exceeding supply (Correct answer)
- A normal response to increasing heart rate
- Increased stroke volume from greater venous return
- Atrial repolarization
Correct answer: Myocardial ischemia from oxygen demand exceeding supply
Horizontal or downsloping ST depression of 1 mm or more with symptoms is a marker of myocardial ischemia.
Ischemia occurs when myocardial oxygen demand (driven by heart rate, wall stress, and contractility) exceeds coronary supply, producing ST-segment depression and often angina. ACSM considers horizontal or downsloping ST depression of 1 mm or more abnormal, and the test should be stopped for angina or marked ST changes. Stroke volume changes and atrial repolarization do not produce ST depression. Rate-pressure product (HR x SBP) is used as an index of myocardial oxygen demand.
Question 3: Which spirometry finding confirms the airflow limitation of chronic obstructive pulmonary disease (COPD)?
- Post-bronchodilator FEV1/FVC ratio below 0.70 (Correct answer)
- FEV1/FVC ratio of 0.85 with a reduced FVC
- Airflow obstruction that completely reverses after a bronchodilator
- Resting oxygen saturation below 90% as the only abnormality
Correct answer: Post-bronchodilator FEV1/FVC ratio below 0.70
COPD is confirmed by a persistent post-bronchodilator FEV1/FVC below 0.70.
COPD is defined by persistent, not fully reversible airflow limitation, shown by a post-bronchodilator FEV1/FVC below 0.70. A normal or high ratio with a reduced FVC suggests a restrictive pattern. Complete reversal with a bronchodilator points toward asthma. Oxygen saturation alone does not diagnose COPD. For exercise, ACSM recommends monitoring SpO2 (keep at or above 88%), using RPE or dyspnea scales, and including pursed-lip breathing.
Question 4: A client's resting blood pressure averages 134/78 mm Hg on two separate visits. According to the ACC/AHA classification used by ACSM, how is this classified?
- Normal
- Elevated
- Stage 1 hypertension (Correct answer)
- Stage 2 hypertension
Correct answer: Stage 1 hypertension
A systolic pressure of 130-139 mm Hg is stage 1 hypertension, even with a diastolic pressure under 80.
The ACC/AHA categories are normal (below 120/80), elevated (120-129 and below 80), stage 1 hypertension (130-139 or 80-89), and stage 2 hypertension (140 or higher, or 90 or higher). The higher category applies when systolic and diastolic fall in different ranges. A mean of 134/78 is stage 1 based on systolic pressure. Individuals with hypertension should still exercise; ACSM recommends 150 or more minutes per week of moderate aerobic exercise, but exercise testing and training are deferred if resting BP is 200/110 mm Hg or higher.
Question 5: Which DXA result meets the WHO diagnostic criterion for osteoporosis in a postmenopausal woman?
- T-score of -0.4
- T-score of -1.8
- Z-score of +1.0
- T-score of -2.6 (Correct answer)
Correct answer: T-score of -2.6
A T-score of -2.5 or lower defines osteoporosis.
WHO defines normal bone density as a T-score of -1.0 or higher, osteopenia (low bone mass) as -1.0 to -2.5, and osteoporosis as -2.5 or lower. A T-score of -2.6 therefore meets the criterion, while -1.8 is osteopenia and -0.4 is normal. Z-scores compare to age-matched peers and are used mainly in premenopausal women and children. Exercise for osteoporosis emphasizes weight-bearing and resistance activity plus balance training, while avoiding loaded spinal flexion.
Question 6: A man has a waist circumference of 106 cm, triglycerides of 180 mg/dL, HDL-C of 52 mg/dL, blood pressure of 124/78 mm Hg, and fasting glucose of 92 mg/dL. How many metabolic syndrome criteria does he meet?
- Four, so he has metabolic syndrome
- Three, so he has metabolic syndrome
- Two, so he does not meet the diagnosis (Correct answer)
- One, so he does not meet the diagnosis
Correct answer: Two, so he does not meet the diagnosis
He meets two of five criteria (waist and triglycerides), but three are required for metabolic syndrome.
Metabolic syndrome requires at least 3 of 5: waist above 102 cm in men (88 cm in women), triglycerides 150 mg/dL or higher, HDL-C below 40 mg/dL in men (50 in women), blood pressure 130/85 mm Hg or higher, and fasting glucose 100 mg/dL or higher. This man meets waist (106 cm) and triglycerides (180), but not HDL (52), blood pressure (124/78), or glucose (92). He has two risk factors, not the syndrome, and still benefits from exercise and weight management.
