Synergistic interaction between exercise and insulin on peripheral glucose uptake

Area of Science:

• Endocrinology and Metabolism
• Exercise Physiology

Background:

• Understanding glucose metabolism is crucial for managing metabolic health.
• The individual effects of insulin and exercise on glucose uptake are well-documented.
• The combined impact of insulin and exercise on glucose metabolism requires further elucidation.

Purpose of the Study:

• To investigate the synergistic interaction between insulin and exercise on glucose metabolism in healthy individuals.
• To quantify glucose uptake during hyperinsulinemia, exercise, and combined conditions.
• To identify the primary tissue responsible for enhanced glucose disposal.

Main Methods:

• Four study protocols involving healthy volunteers.
• Insulin clamp technique to induce hyperinsulinemia.
• Bicycle exercise at 40% of VO2 max.
• Measurement of leg glucose uptake using femoral artery and vein catheterization in one protocol.

Main Results:

• Insulin clamp alone increased glucose uptake to 8.73 mg/kg/min.
• Exercise alone increased peripheral glucose uptake by 1.43 mg/kg/min.
• Combined insulin and exercise resulted in significantly higher glucose uptake (15.06 mg/kg/min, P < 0.01) than the sum of individual effects.
• Increased glucose uptake correlated with increased leg blood flow (r = 0.935, P < 0.001).
• Skeletal muscle accounted for over 85% of total body glucose metabolism.

Conclusions:

• Insulin and exercise exhibit a synergistic effect in enhancing glucose disposal in humans.
• The observed synergism is likely mediated by increased muscle blood flow and capillary surface area.
• Skeletal muscle plays a primary role in increased glucose metabolism under hyperinsulinemic and exercise conditions.