A primer on cortisol and adrenaline and blood sugar

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.


Thanks! Curious about minimal stress situations. Best example would be driving. In most long drive scenarios I do not feel stressed out at all, but my BG rises and I assume I am battling insulin resistance. My endo says BG rise while driving is likely caused by stress that I have become used to but is still there in the background. Is that insulin resistance behind the steering wheel caused by cortisol or is it caused by sitting on my butt?


Maybe something like that could be partly due to stress, but probably more of it is that you are sitting still for a long time.

If you think about being at home, even when you are not active, you still move around some. Like if you get up to go to a different room or go to the kitchen or whatever.

But when you are driving, you really are sitting in one place for a long time. I think the only time I sit still is when I am driving.


We just came back from a long car trip - from Massachusetts to South Carolina and back - and it was a reminder about how basically unhealthy driving is. Like you say, you are not moving around, so you don’t get any exercise. Plus your body (particularly your back) is not used to maintaining that driving position for long periods. Both my wife and I have bad backs, and we really noticed it after a 5 or 6 hour drive.

Our trip was an experiment - how do we do with driving vacations? The answer – not so great.


I have experienced the problem on every driving trip I’ve done the past few years and still searching for a solution. My trips are in a camper van, stringing together 400 mile days to get from west coast to the Tetons and Rockies. It gets worse when multiple days of driving pile up. I’ve tried various temp basal increases but have not gotten super aggressive with those.

Usually I will stop every few hours and get outside/walk/stand. One trick I’ve had some success with is combining frequent correction bolussing with a 10-minute brisk walk with every bolus. Seems to help in a hard to measure way.


That’s hard when you are trying to get somewhere in a hurry! I’ve been thinking of taking a road trip of about 14 hours and BGs is one of my main concerns. I don’t usually drive much so 14 hours would be a big deal. My thought would be to look for a few parks along the way and try to stop to get some exercise, similar to your trick, @John58!


If you exercise hard the night before, that can also help keep your BG in check the next day.


hmm, Eric defines hard as running 2 marathons in a day, good luck peasants!


Good point, @Chris ! :rofl:


You, and everyone on FUdiabetes is simply amazing! Thank you for your sharing your experiences, knowledge, wisdom and kindness.


Happy to be here, and Glad you are too @SFLADA, it is community that makes the world worth living in, and FUD and its members are awesome.