Exercise is known to increase insulin sensitivity; which statement best explains why this would affect insulin needs?

Exercise is known to increase insulin sensitivity; which statement best explains why this would affect insulin needs?

• A. Increased hepatic glucose output
• B. Increased insulin receptor sensitivity
• C. Decreased muscle glucose uptake
• D. Decreased glucagon production

Answer: (B)

Regular exercise boosts how responsive tissues are to insulin, so the same amount of insulin lowers blood glucose more effectively. The key change is improved insulin signaling in skeletal muscle, which includes more GLUT4 transporters moving to the muscle cell membrane. With these transporters available, glucose enters muscle more readily per unit of insulin, meaning you don’t need as much insulin to get the same glucose-lowering effect. The other ideas don’t explain the reduced insulin needs as well: hepatic glucose output can actually rise during exercise to fuel working muscles, which would tend to require more insulin, not less; muscle glucose uptake is increased, not decreased; and while hormone shifts occur, the central reason for needing less insulin is the heightened insulin receptor signaling and GLUT4-mediated glucose uptake in muscle.

Regular exercise boosts how responsive tissues are to insulin, so the same amount of insulin lowers blood glucose more effectively. The key change is improved insulin signaling in skeletal muscle, which includes more GLUT4 transporters moving to the muscle cell membrane. With these transporters available, glucose enters muscle more readily per unit of insulin, meaning you don’t need as much insulin to get the same glucose-lowering effect.

The other ideas don’t explain the reduced insulin needs as well: hepatic glucose output can actually rise during exercise to fuel working muscles, which would tend to require more insulin, not less; muscle glucose uptake is increased, not decreased; and while hormone shifts occur, the central reason for needing less insulin is the heightened insulin receptor signaling and GLUT4-mediated glucose uptake in muscle.