What is the function of exercise-induced catecholamines in energy mobilization during exercise?

What is the function of exercise-induced catecholamines in energy mobilization during exercise?

• A. Insulin stimulates energy mobilization
• B. Cortisol inhibits energy release
• C. Catecholamines (adrenaline/noradrenaline) stimulate glycolysis, glycogenolysis, and lipolysis, increasing availability of glucose and free fatty acids for energy during exercise
• D. Thyroid hormones do not affect energy mobilization

Answer: (C)

During exercise, the body rapidly activates the sympathetic system, releasing catecholamines (adrenaline and noradrenaline) to fuel the working muscles. These hormones switch on quickly to mobilize energy substrates. They raise glucose availability by promoting glycogen breakdown (glycogenolysis) in liver and muscle and by accelerating glycolysis in the muscle, so ATP can be produced rapidly. At the same time, they stimulate lipolysis in adipose tissue, releasing free fatty acids into the bloodstream for use as a slower, sustained energy source. The combined effect is a quick boost of glucose and free fatty acids in circulation, ensuring muscles have the fuel they need as exercise continues. This rapid energy mobilization is why catecholamines are central to fueling activity, whereas insulin tends to oppose mobilization, cortisol provides longer-term energy support, and thyroid hormones influence overall metabolic rate but don’t drive the immediate energy release during exercise.

During exercise, the body rapidly activates the sympathetic system, releasing catecholamines (adrenaline and noradrenaline) to fuel the working muscles. These hormones switch on quickly to mobilize energy substrates. They raise glucose availability by promoting glycogen breakdown (glycogenolysis) in liver and muscle and by accelerating glycolysis in the muscle, so ATP can be produced rapidly. At the same time, they stimulate lipolysis in adipose tissue, releasing free fatty acids into the bloodstream for use as a slower, sustained energy source. The combined effect is a quick boost of glucose and free fatty acids in circulation, ensuring muscles have the fuel they need as exercise continues. This rapid energy mobilization is why catecholamines are central to fueling activity, whereas insulin tends to oppose mobilization, cortisol provides longer-term energy support, and thyroid hormones influence overall metabolic rate but don’t drive the immediate energy release during exercise.