ACSM Exercise Physiology 5

Question 1

During prolonged exercise lasting 2+ hours, hypoglycemia can impair performance primarily because:

Accepted Answer

The central nervous system relies heavily on glucose as fuel

Answer

The brain depends almost exclusively on glucose; hypoglycemia impairs CNS function, leading to fatigue, confusion, and cessation of exercise.

Question 2

Which of the following best describes the effect of dehydration equivalent to 2% of body weight on aerobic exercise performance?

Accepted Answer

Up to 20% decrease in aerobic performance capacity

Answer

A 2% body weight deficit from dehydration can reduce aerobic performance by approximately 10–20% due to decreased plasma volume and cardiac output.

Question 3

Muscle glycogen resynthesis after prolonged exercise is maximized when carbohydrate is consumed:

Accepted Answer

Within 30–60 minutes after exercise ends

Answer

Glycogen synthase activity and muscle insulin sensitivity are highest immediately post-exercise, making early carbohydrate intake critical for rapid resynthesis.

Question 4

Which phenomenon explains why trained endurance athletes oxidize more fat and less carbohydrate at a given absolute submaximal workload compared to untrained individuals?

Accepted Answer

Training-induced increase in mitochondrial density and fat oxidation enzymes

Answer

Aerobic training increases mitochondrial density and enzymes such as citrate synthase, enabling greater fat oxidation at the same absolute workload.

Question 5

What is the primary mechanism by which beta-blockers limit exercise performance?

Accepted Answer

They blunt the catecholamine-mediated increase in heart rate, limiting maximal cardiac output

Answer

Beta-blockers block beta-1 adrenergic receptors on the heart, preventing the catecholamine-driven heart rate increase and thus limiting maximal cardiac output.

ACSM Practice Test

ACSM Practice Test

ACSM Exercise Physiology 5