What Does Cortisol Do to Help Maintain Blood Glucose Levels During Fasting?

Cortisol is often regarded as the “stress hormone.” It is important to realize that fasting, especially prolonged fasting, is a form of stress—and stress results in the release of cortisol from the adrenal glands along with epinephrine mentioned in the previous question. Cortisol also supports the breakdown of glycogen and the conversion of amino acids, lactate,

and glycerol to glucose in our liver. Because cortisol also promotes the breakdown of our body protein, especially skeletal muscle protein, it ensures a supply of amino acids for conversion to glucose in our liver (Figure 4.5).

Exercise promotes the breakdown of carbohydrate stores in muscle.