Ex Phys Hormonal Responses to Exercise and Metabolic Effects

The two major effects are the regulation of blood glucose levels and the mobilization of free fatty acids (FFA) for energy.

What are the two major effects of the hormonal response to exercise?

Epinephrine and norepinephrine are released from the adrenal medulla, promoting glycogen breakdown and increasing blood glucose. Glucagon is released from the pancreas to raise blood glucose levels. Insulin, also from the pancreas, lowers blood glucose. Growth hormone is released from the anterior pituitary and promotes protein synthesis and fat mobilization. Cortisol, released from the adrenal cortex, helps maintain blood glucose levels during prolonged exercise.

What hormones are involved in the exercise response, and what are their sites of release and basic actions?

Higher intensity and longer duration of exercise increase muscle glycogen breakdown, which is controlled by catecholamines (like epinephrine) and intracellular calcium levels.

How does exercise intensity and duration affect muscle glycogen breakdown?

Insulin decreases blood glucose and FFA levels, while glucagon increases them. During exercise, plasma insulin levels decrease and glucagon levels increase to maintain energy availability.

What is the role of insulin and glucagon in regulating blood glucose and FFA levels during exercise?

Epinephrine increases blood glucose and FFA levels by promoting glycogenolysis and lipolysis. Exercise increases plasma epinephrine concentration.

How does epinephrine affect blood glucose and FFA levels during exercise?

Cortisol increases blood glucose levels by promoting gluconeogenesis and lipolysis, while growth hormone enhances FFA mobilization and reduces glucose uptake in tissues.

What roles do cortisol and growth hormone play in controlling blood glucose and FFA levels?

During exercise, growth hormone promotes fat mobilization and preserves glucose. In recovery, it aids in tissue repair and muscle growth.

What are the different effects of growth hormone during exercise compared to recovery?

Hormone-sensitive lipase facilitates the breakdown of stored triglycerides into free fatty acids for energy during light to moderate exercise.

What is the role of hormone-sensitive lipase in FFA use during light to moderate exercise?

Rising blood lactate levels during intense exercise inhibit hormone-sensitive lipase, blocking FFA mobilization and utilization.

How does rising blood lactate during intense exercise affect FFA mobilization?