Cortisol Isn’t the bad guy (Chronic Stress Is!!)
If you’ve spent more than five minutes on the wellness side of the internet, you’ve probably seen cortisol blamed for everything: “stubborn belly fat,” afternoon energy crashes, burnout, poor sleep, “unbalanced” hormones, and the list goes on.
And somehow, the solution is always a supplement, a specific workout, or a strict dietary regimen.
But cortisol isn’t out to get us; it’s actually a normal, necessary hormone that helps us wake up, focus, respond to stress, train hard, and recover from said training.
There is not a problem with cortisol itself, but what happens when stress never lets up and recovery never catches up.
Let’s break down what cortisol actually does, why it gets so weaponized online, and what actually matters if you’re feeling run-down, stuck, or overwhelmed.
(And if you want the full, nuanced, research-backed conversation — we go much deeper on this in the full How to: Fitness podcast episode.)
What Is Cortisol, Really?
Cortisol is a hormone made by your adrenal glands. When your brain senses a challenge — physical, mental, or emotional — it activates the HPA axis (a brain-to-body communication pathway) and releases cortisol.
That release:
Increases blood sugar to mobilize quick energy
Sharpens focus
Temporarily downshifts non-essential systems like digestion and reproduction
This is helpful and it’s how our bodies handle stress on purpose.
Something that often gets missed in the discussion of this hormone is that cortisol isn’t just a “stress hormone.” It follows a daily rhythm, peaking in the morning to help you wake up, then gradually declining throughout the day so you can wind down at night. It also plays a role in immune function, inflammation control, tissue repair, and metabolism.
Normal Cortisol Spikes vs. Chronic Stress
A quick spike in cortisol is not a problem. Cortisol will spike due to coffee in the morning, an intense workout, a big work meeting, or waking up extra early.
These all cause short-term, adaptive increases in cortisol which will come back down in time.
A much bigger issue is chronic elevation of cortisol, where stress stays high for long periods of time without adequate rest and recovery.
That kind of stress usually isn’t coming from a single workout or food choice.
What Drives Chronically High Cortisol
Ongoing mental and emotional stress: Long stretches of work pressure, financial strain, caregiving, or relationship stress can keep your nervous system in a near-constant state of alert. Your body doesn’t really know the difference between an overflowing inbox and a true physical threat (stress is stress to our physiology!).
Consistently poor sleep: Both sleep quantity and quality matter. Even mild, repeated sleep disruption can interfere with cortisol’s natural rise-and-fall pattern, making it harder for your system to fully recover and handle everyday stress.
Training hard without enough recovery: Exercise is meant to be a helpful stressor. When high-intensity training stacks up without adequate rest, fuel, or lower-intensity days, cortisol can stay elevated longer than intended.
Chronic underfueling or restrictive dieting: Regularly eating too little, skipping meals, or living in a prolonged calorie deficit increases physiological stress. Research shows that very low-calorie intake and rigid food control can nudge cortisol higher over time.
Underlying medical factors: Less common, but important to mention: conditions like Cushing’s syndrome, long-term corticosteroid use, or certain chronic illnesses can elevate cortisol. If symptoms feel extreme or persistent, this is something to explore with a medical professional.
Cortisol and Exercise (Where we Lose the Plot)
You’ve probably heard:
“HIIT spikes cortisol — it’s bad for women.”
“Running raises cortisol — you’ll gain belly fat.”
“Lifting heavy will ruin your hormones.”
Not only are these broad generalizations that do nothing but stoke fear in exercise (when in reality, it’d be beneficial to most individuals health if they moved more) but they’re also confounding the reality that exercise does raise cortisol with something that’s a “problem.”
Exercise raises cortisol temporarily — and it’s not a bad thing. When you train, especially at moderate to high intensity, cortisol helps mobilize fuel, increase alertness and attention, and supports your overall performance.
It’s like your body saying, “Alright, we’ve got work to do.”
Assuming you recover well, that cortisol spike will come back down. This stress-recovery cycle is how adaptation happens, allowing us to get fitter, stronger, and more resilient.
The problem isn’t that exercise raises cortisol; the problem is if/when training becomes one more stressor piled on top of an already overloaded system.
The Supplement Industry Loves Cortisol Fear
If you start to search cortisol online, I guarantee you’ll immediately be hit with countless supplements:
Cortisol blockers.
Adrenal tonics.
Hormone-balancing teas.
Mushroom powders with big promises (and even bigger price tags).
In our full podcast episode, we go into more specifics on the reality of these supplements but here’s the short version: most of these are a waste of money.
“Cortisol Blockers” - Blocking cortisol outright would actually be dangerous. You need cortisol to survive. The idea that you should “turn it off” isn’t just oversimplified — it’s biologically irresponsible.
“Adrenal Fatigue” Supplements - Adrenal fatigue is not a recognized medical condition. True cortisol disorders (like Cushing’s or Addison’s disease) are serious medical conditions diagnosed and treated by physicians.
Adaptogens - Some adaptogens (like ashwagandha) show modest promise for stress support in certain situations. But their effects are small, mixed, and highly individual — and they work best alongside lifestyle changes, not instead of them.
If you’ve already addressed the basics, a few supplements may be supportive for general stress management:
Magnesium (sleep and relaxation)
Omega-3s (brain and inflammation support)
L-theanine (calm focus)
Ashwagandha (modest stress support for some people)
None of these replace sleep, food, recovery, or boundaries.
Should You Test Your Cortisol?
For most healthy people, routine cortisol testing creates more confusion than clarity. Cortisol naturally fluctuates throughout the day, and without a clear medical reason, testing often leads to unnecessary worry.
If you’re experiencing significant, persistent symptoms — especially red flags like rapid central weight gain, severe fatigue, muscle weakness, or very high blood pressure — that’s a conversation for your doctor.
How We Can Actually Support Cortisol Levels
What feels important first and foremost is not being fearful of cortisol, because it’s not a bad thing! Supporting our cortisol levels looks similar to many other foundational habits we want to practice.
Sleep: Aim for consistent quantity and quality. If you struggle with sleep, it may be worth refining your sleep hygiene at night.
Fuel: Eat regular meals with enough total energy, protein, and carbs. If you’re in a calorie deficit, make sure it’s not too prolonged.
Train purposefully: Strength train a few times a week, condition intentionally, walk often.
Set aside time for rest and recovery: This means easy workout days, deload weeks, screen-free downtime.
Audit stress levels: There are often stressors with work, family, and friends that we cannot control. However, there may be other areas where you can bring down your stress levels and it’s worth doing so wherever you can.
Pay attention to your body’s feedback: Energy, mood, sleep, cravings, and performance are all data points that help us stay in tune with our bodies and recognize where we’re supporting ourselves well and where there is room for improvement.
If you want more nuance, real-world examples, and the research we referenced, listen to the full episode of the How to: Fitness podcast where we unpack cortisol, exercise, and stress without fear-mongering.
Need more no-nonsense nutrition information in your life? Sign up for my weekly email each Friday. Get nutritional nuggets, recipes, troubleshooting, and more reasons to ditch restrictive diets and find a flexible (and enjoyable) approach to your nutrition.
Kate Lyman
Leader, nutrition educator, and former chronic dieter helping clients rebuild their relationship with food, escape the cycle of yo-yo dieting for good, and cut through the overwhelm of nutrition misinformation.
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