Endocrine System Responses to Exercise | Exercise Science

In this article and therefore the next, I will be able to address the role of the system in regulating many essential physiological and biochemical adjustments made by the body in response to exercise. The system may be a collection of glands that produce and secrete specific hormones into the blood while there are numerous endocrine glands within the body. I will be able to specialize in only three.

Endocrine System Responses to Exercise


Endocrine System Responses to Exercise

The pancreas is liable for the assembly and release of insulin and glucagon, both of which play a critical role in carbohydrate metabolism during exercise. The adrenal glands and specifically the medulla produces epinephrine and norepinephrine, which have multiple effects and therefore the regulation of the many key physiological and biochemical adjustments made by the body in response to exercise.

Finally, I will be able to adjust the role of the expansion hormone released from the anterior pituitary gland. First, let's briefly review a number of the essential characteristics of hormones, hormones are trace substances produced and secreted by various endocrine glands, which are then carried within the blood to varied target tissues.

At these target tissues, hormones regulate a spread of physiologic and metabolic functions as they react with their specific receptors present in or within the right direction not off course"> on track tissues as they circulate in the blood. Hormones have the power to succeed in all tissues within the body. Lastly, I wish to stress that the system works closely with the system nervous to take care of homeostasis during the physical stress of exercise.

Hormone insulin

Let's begin with the hormone insulin, insulin is produced and secreted from the beta cells within the pancreas, it's responsive after a meal when the blood is rich in macronutrients with an elevation in blood sugar concentration being a serious stimulus for its release. Shown here is that the normal fasting range for blood sugar levels, ideally in healthy adults, blood sugar level should be between 70 and 100 milligrams of glucose per 100 milliliters of blood.

During this figure, the insulin response after a meal when blood sugar levels are high is indicated by the blue arrows. the rise in blood sugar levels directly stimulates the pancreas to release insulin into the blood, thereby elevating blood insulin levels. Insulin will now promote glucose uptake in most cells for fuel, but within the case of striated muscle and therefore the liver, the glucose haunted are going to be primarily wont to replenish your glycogen stores that are somewhat depleted since your last meal.

This table demonstrates the metabolic effects of insulin and glucose uptake and storage as glycogen in muscle and liver. Please notice that when these glycogen stores are completely replenished, any excess glucose from the meal is going to be converted into fat and both liver and fat. We'll revisit this idea once we discuss weight control and obesity in the module.


Whether you're engaging in submaximal, steady-state exercise or a graded exercise test to exhaustion, insulin levels decline during exercise. This decline in blood insulin levels, when including the reduction in blood flow to non-active tissue like adipose and inactive muscle, will minimize glucose uptake by these tissues.

Thus the glucose within the blood is often preferentially employed by the active muscles where it's needed. Also, it's vital to understand that although insulin levels are decreasing during exercise by the maximum amount of 50 percent, blood flow to the active muscles can increase 10 to fifteen-fold. Thus, the act of muscles actually sees more insulin during exercise as insulin promotes glucose uptake in muscle, this may enhance the exercising muscle's ability to extract glucose from the blood and use it for fuel.

Lastly, exercise training leads to a big improvement in insulin sensitivity. This has major implications for the treatment of Type two diabetes, 90 to ninety-five percent of all diabetics have Type two diabetes, which is primarily caused by a rise in insulin resistance.

As we'll see in module four, there's no pill or technique simpler than regular exercise to enhance insulin sensitivity for the treatment of Type two diabetes. As shown here, the uptake of glucose from the blood during exercise can increase up to twentyfold in comparison to the remainder.

Extent of glucose uptake

As usual, the extent of glucose uptake is going to be dependent upon the exercise, intensity, insulin levels, and muscle blood flow. The second hormone that plays a critical role in carbohydrate metabolism and glucose homeostasis during exercise is glucagon. Glucagon is produced and secreted by the alpha cells within the pancreas.

Glucagon's primary function is to take care of blood sugar concentration when levels drop below normal, as is that the case during the time between meals, fasting, and in fact, during exercise. It accomplishes this function by activating liver glycogen breakdown, leading to the discharge of the newly formed glucose into the blood.

Glucagon guns, well, during exercise are shown here, highlighted by the red arrows. At the onset of exercise, blood sugar levels dropped below normal as working muscles extract glucose from the blood for fuel. This decrease in blood sugar levels stimulates the discharge of glucagon from the pancreas. The elevation of glucagon levels within the blood will activate glycogen breakdown within the liver, leading to the discharge of glucose into the blood.

As such, the working muscles will still have a source of glucose for fuel and eventual ATP production as long as liver glycogen stores hold out. This table demonstrates the metabolic effects of glucagon and glucose production and released by the liver as are often seen, glucagon primary function is to break down liver glycogen supply and free glucose to be released into the blood.



However, a second row for glucagon is to stimulate glucan, the agenesis within the liver, this pathway allows the liver to form glucose from non-carbohydrate precursors like amino acids and fats. this is often particularly important during prolonged exercise when liver glycogen stores are depleting.

This provides a private a non-carbohydrate source for glucose production to catch up on diminishing carbohydrate stores. Thus, during prolonged exercise, glucagon levels rise to increased glucose output by the liver to match glucose uptake by active skeletal muscles, thereby maintaining blood sugar concentrations. Notice that endurance-trained individuals have a blunted glucagon response to exercise in comparison to untrained individuals.

This is often the result of their greater ability to utilize fats and rely less on blood sugar. Thus, blood sugar levels will drop less and trained individuals. So there's less of a requirement for a glucagon response. In summary, insulin plays a serious role in the significant increase in muscle glucose uptake during exercise, glucagon plays a serious role in maintaining blood sugar levels during exercise. Together, both insulin and glucagon make sure that working muscles have an adequate source of fuel for ATP production.


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