Blood sugar and hormones have been discussed a million times here, but I couldn’t really find a single post that gives a simple explanation or simple summary for how and why certain hormones cause your blood sugar to rise, and how they each do it in different ways.
This is a very basic summary. Just a little primer on the subject.
I want to give an explanation on 2 hormones - cortisol, and adrenaline (epinephrine). And give a simple explanation of why they cause a blood sugar rise, and how they are different in the way they cause the blood sugar to rise.
Keep in mind, the body is constantly using almost everything. It isn’t like “on” or “off”. It is just different levels or degrees of all the hormones. Always working together, just in different amounts.
First of all, glucose is the easiest and fastest fuel source for the body. While fat is more abundant, glucose can be used for higher intensity activities. So in situations of stress, the body is going to want to make sure it has glucose available for the “emergency”.
The liver is the body’s fuel regulator. It takes in glucose when there is excess, and it releases glucose when it is needed. In stressful situations, the body wants to have fuel.
Let’s look at a simple scenario to try to illustrate cortisol and adrenaline…
You are waking through a dangerous part of town late at night. You are all alone. You are nervous about your safety. What if someone approaches? Your body wants to make sure it has sufficient fuel to either fight or flee. At this point, the stress hormone cortisol will be released, to make sure you have sufficient fuel.
Cortisol will cause insulin resistance. We don’t want to store glucose, we want to have it available right now! So instead of allowing the body to take in glucose and store it in the muscles and liver, it wants to keep it available. Cortisol inhibits glucose uptake in peripheral tissues. It also stimulates the body to create glucose from non-glucose sources (fat). So the end result is more glucose available in the blood, insulin being inhibited, and higher blood sugar.
You keep walking through the dangerous area. Suddenly somebody jumps out with a knife and demands your money. You start running away as fast as you can. Now we see adrenaline (epinephrine). Your body wants to make sure you have fuel to run away. So adrenaline causes your liver to release stored glucose - fuel to run away from the danger. The released fuel (glucose) will of course cause a rise in blood sugar.
The 2 hormones in this example also do many other things, like increase heart rate and raise blood pressure, to help the body cope with the emergency, and to trigger blood vessels to contract and re-direct blood toward major muscle groups, the heart, and the lungs.
And all of these things work together, it is not one or the other. (Like adrenaline also cause insulin resistance in concert with the release of glucose.) And again to emphasize, it is never simply one or the other. They work in tandem, in different amounts.
Also, this is an overly-simplified explanation. Not getting into things like glycogenolysis and gluconeogenesis and glycogen phosphorylase and glycogen synthase.
This is just a simple explanation on how stressful situations can cause a rise in BG, how it happens, and the different ways they can cause a rise in BG.