Free US shipping & free frother with your first Starter Kit subscription order

  woman holding a mug of coffee
< Back

How Caffeine Affects Cortisol—Your Body's Main Stress Hormone

An essential guide to coffee and stress

Rae Repanshek

Hi, my name is Rae, and I was addicted to coffee. I was an “I’ll take four extra shots of espresso” in my venti iced white mocha type of girl, an “I can’t—I haven’t had my coffee yet” type of girl, and an “It’s a top knot, double shot kind of day” type of girl. I could go on, but you get the point.

When I quit drinking coffee years ago, it wasn’t because I didn’t like coffee anymore. It was because I didn’t like how it made me feel anymore. And that’s an important distinction. I still love the smell, the taste, and I have many fond memories of me and coffee. But I don’t love that it would jolt my nervous system and put me into fight or flight mode before I even started my day. I didn’t really need to wake up with “I’m going to take down a bear today” energy. 

Not to mention, coffee just wasn’t doing what I wanted it to do. I wanted it to pump me up, and give me the focus and energy I needed to run all my errands, clean the house, mow the lawn, organize the garage, and tackle what felt like hundreds of other things I had to do that day. Instead, it left me frantic, anxious and feeling like my heart was beating faster than a hummingbird’s. And forget about focus—my attention span was nearly nonexistent. At the end of the day, I didn’t accomplish what I wanted to, I didn’t feel good and was just plain stressed

And looking back on it, it makes me wonder … Does coffee increase stress? Or was I just leading a stressful life? (Maybe both?)

To answer the first question, I needed a refresher on how coffee works so I sat down with my friend Dr. Mary Pardee, a Naturopathic Medical Doctor and a Certified Functional Medicine Doctor, to learn more.  

How Does Caffeine Work? 

Caffeine is a stimulant that directly affects your central nervous system. Its short-term effects can hit after just a few minutes, as it’s quickly absorbed into the bloodstream (NLM). 

“It's also an adenosine receptor antagonist. The buildup of adenosine throughout the day is what increases your sleep drive,” Pardee says. “When we block that, it blocks the effect of adenosine so that you don't get sleepy.”

In other words, caffeine tricks your brain into thinking it’s more awake than it is and that’s why you feel so alert. The half-life of caffeine is five to seven hours, so depending on when you had your last cup of coffee you may still have some caffeine in your system at night which could make it difficult to sleep.

But how much it stimulates your brain, how long it stays in your system and how it makes you feel, is highly personal. That’s because the CYP1A2 gene encodes the enzymes that metabolize caffeine (NLM). So you may be able to drink a pot of coffee in the morning and feel fine, while your friend may have just half a cup and still feel the effects several hours later. 

How Does Stress Work? And How Does Caffeine Impact Stress?

During times of stress, your body activates its sympathetic nervous system. Your brain may also release cortisol after releasing its “fight or flight” hormones, such as adrenaline, so you continue to stay on high alert. This is a perfectly normal response. 

“When we talk about the stress response, cortisol can increase,” Pardee says. “You can also have increases in your other stress hormones, norepinephrine and epinephrine. And that's really paramount to the bodily functions that you would need to then carry out the stressor.”

Our body’s stress response is an important physiological mechanism. We need to be able to respond to stress. But we don’t want to sit in a prolonged stress response or exist in that state constantly. A short bout of stress that lasts a few seconds or minutes is not only normal and healthy but also necessary. 

“It's rooted in what we used to have as stressors, like if you think about the example of a lion or tiger coming at us,” Pardee says. “And so all of those stress hormones are going to then increase our heart rate, increase the blood flowing to our arms and legs so we can either fight or we can run. It's going to reduce sleepiness. It's gonna do all of these things to make sure that we can actually handle the stressor and we want that.”

That's one of the reasons people use coffee or caffeine as an ergogenic aid to increase energy, performance and recovery. It might help you run longer or do the workout that you want but if you're not in that exercise mode you may perceive that extra dose of caffeine as stressful. You may notice anxiety or jitters because you're asking your body to produce that same response but you're just sitting at your computer versus running or fighting. Some people may love that feeling—it may feel like motivation—but I didn’t love it, which I stopped drinking coffee.

Does Coffee Increase Stress? 

Coffee itself doesn’t increase stress, but consuming caffeine can raise cortisol levels which may be perceived as an increase in stress. So it’s important to be mindful of how much you're consuming and how your body responds to it. 

“One of the effects caffeine has is increasing cortisol levels,” Pardee says. “Another effect that it has is increasing dopamine levels, which is why sometimes when we have caffeine we feel more motivated and we want to get stuff done.”

And cortisol isn’t a bad thing—it’s also what regulates your metabolism, inflammatory response and immune function (NLM). But that’s all the more reason to keep your cortisol levels balanced.

“How does drinking coffee make you feel when you're stressed? If your answer is ‘it helps me get through it’ and you feel good, then great,” Pardee says. “If you’re drinking normal amounts and it's helpful for you, then great. But everyone’s different. If you asked me I'd be like, I feel like I'm running around with my head cut off and I'm anxious and I can't keep my mind straight. And then my advice would be, don't do it. Reduce your caffeine intake.”

What Should You Do About Caffeine and Stress?

If you’re concerned about your stress levels and you drink a lot of caffeine, you may want to consider reducing your caffeine intake.  

“The research shows that stress can have detrimental effects on our health,” Pardee says. “Perpetual stress on the body is associated with a lot of health concerns.”

When I drank coffee every day it felt like I was in a state of chronic stress, and nearly all that stress went away when quit. These days, I’m much more focused and calm, and I actually have more energy than I did when I was drinking coffee. So, if you’re wondering whether the same might be true for you, Pardee recommends reducing your caffeine intake for a while and seeing whether lessens your stress levels.

“The best thing you can do is do a self-trial and take yourself off of it,” Pardee says. “See how you feel. And then potentially reintroduce it because I think that gives you more information. Do it twice and you see how you feel again. And then ask yourself, is there jitters? Is there anxiety? Is there a worsening of perceived stress levels? Because we know that caffeine can have effects on all of those things.” 

It’s wild to me that caffeine is the most widely used psychoactive drug in the world (NLM) and that for most Americans, that morning cup (or pot) of coffee is a normal part of their daily routine. And it’s even wilder for me to think that I used to be one of those people and would absolutely depend on coffee to get through my day even though it just made me feel frantic and stressed. But just like any other aspect of health, how much caffeine you drink is up to you. What’s best for me may not be what’s best for you, so my best advice is to get curious and listen to your body. 

Rae Repanshek is MUD\WTR's talented copywriter.

Similar Reads

  • The Environmental Impacts of Coffee
    Alexa Peters
  • The History of Bicycle Day
    Damon Orion
  • Does Ayahuasca Really Cleanse Toxins From the Body?
    Damon Orion
  • MUD\WTR Mushrooms—Separating Fact From Fiction
    Katie Maloney

Friday newsletter

Get to first base with enlightenment