More than a century ago, the American physiologist Walter Cannon found that animals under threat slip into a "fight or flight" state — heart racing, blood surging to the limbs, ready to scrap or sprint. Later, the Hungarian physician Hans Selye turned this into a full "stress" theory and earned a place in medical history. Neither of them could have guessed that the alarm system that helped our ancestors dodge predators is now being pressed all day by something far more stubborn — not a wild animal, but the unread messages on your phone.
And the finger holding down that alarm is called cortisol.
Cortisol isn't the villain: it's the body's "horn"
Cortisol gets a bad rap as the "stress hormone," but it isn't the antagonist. It's a hormone made by the adrenal glands, and its job is to help you handle moments that need focus — waking you in the morning, keeping you alert in a meeting, mobilizing energy in danger. Together with adrenaline, it forms the body's "stress response": it sounds when something comes up, and goes quiet once it's over.
A glucocorticoid involved in blood sugar regulation, immune response, blood pressure, and mood management. In a healthy state it follows a "rhythm": highest in the early morning to get you up, lowest late at night so you can sleep. The problem isn't that it appears — it's that it doesn't switch off when it should.
Here's an analogy: cortisol is the horn on your car. A tap is a courtesy to the car ahead; holding it down is road rage. Chronic stress is the finger that never lets go of the horn.
A day of cortisol: walking through the rhythm
Healthy cortisol isn't "the lower, the better" — it's "high when it should be high, low when it should be low."
Cortisol has almost bottomed out, and your body runs on melatonin to stay asleep. Being woken now is extra rough, because your "standby mode" is at its shallowest.
The sun rises, cortisol climbs with it, "waking up" your blood pressure and blood sugar — and you wake naturally. The more regular this "morning peak," the more energy you have during the day.
It holds a mid-to-high level to support work and study. Caffeine adds "fuel" here — but too much, and the afternoon is a crash waiting to happen.
Cortisol gradually drops as your body prepares for night. Pushing a late-night sprint at this hour is working against your biological clock.
This is when you should be sleeping soundly. If it chronically "refuses to fall," you'll lie awake or wake easily at night — that's a rhythm out of tune.
So when judging a stress problem, don't just stare at "is cortisol high or low" — look first at "is it on time." Rhythm tells you more than the number.
Chronic stress: when the horn never stops, what happens to the body
When stress drags on, your body keeps thinking "danger isn't over," so cortisol stays elevated. You don't feel it at first — but over time, the cost gets written on your body line by line:
| Dimension | Acute stress | Chronic stress |
|---|---|---|
| Trigger | Sudden: a deadline, public speaking, a hard brake | Endless: the work group chat, the mortgage, constant self-demand |
| Cortisol | Spikes fast, then settles once it's over | Stays elevated — "doesn't fall when it should" |
| Body response | Fast heartbeat, sweaty palms — but it recovers | Insomnia, bloating, catching colds, emotional tension |
| Recovery | Rest a bit and it's fine | Needs long-term changes to rhythm and habits |
The most typical picture in the research: under prolonged stress, sleep turns shallow, appetite goes haywire (either no appetite or a compulsion for sweets), and emotions feel like a lid you can't hold down on a boiling pot. And most of the time, it isn't caused by "one thing" — it's dozens of small things stacking up: the messages in the work group, the crowded commute, the bills at night.
Chronic insomnia, abnormal weight swings, and extreme fatigue can also be signs of thyroid problems, anemia, or Cushing's syndrome. If symptoms persist and are severe, see a doctor for tests first — don't just comfort yourself with "it's just stress."
Self-check: is your stress system "stuck"?
- Have you been "sleeping 8 hours and still tired," or even more tired the more you sleep? (A classic sign of a disrupted cortisol rhythm.)
- Do you get restless and jittery the moment you have nothing to do, and feel you must find something to occupy yourself? (Your body has gotten used to "always sounding.")
- Do you often forget when you last truly relaxed — not scrolling your phone, but genuinely slowing down? (The ability to relax is something you have to practice.)
| Signal | Often misread as | Doable today |
|---|---|---|
| "8 hours of sleep and still tired — more tired the more I sleep" | "I'm just lazy" | Skip the catch-up nap; get 10 minutes of morning sun to recalibrate your rhythm |
| "Restless the moment I'm idle, can't sit still" | "I just can't relax" | Carve out 10 blank minutes a day — do nothing, and practice pressing the brake |
| "My mind won't stop, worse before bed" | "I'm too anxious, can't be fixed" | Breathe in for 4 seconds, out for 6 — longer exhales, 2–3 minutes before bed |
If all three hit, don't rush to blame yourself. This isn't a willpower problem — it's the natural response of a body that's been in "battle ready" for too long. What follows is how to step-by-step press the brake down.
Why "just relax" doesn't work for chronic stress
Behind elevated cortisol is a real physiological state, not a thought. Research shows long-term cognitive load and physiological stress reinforce each other: the more you tell yourself "stop worrying," the more you strengthen the anxiety loop. Instead of telling yourself to relax, do something physical — breathing, movement, sleep — so your nervous system actually feels "safe."
It's also why so many people "catch up on sleep" on weekends and still feel tired: a nap refills sleep, not a stress system that never switched off. The brake has to be pressed through daily actions.
"Just relax" isn't a cure, but it isn't nonsense either — it just skips the most important step: let the body actually clock out first, then talk about mindset.
TCM view: stress drains your "qi"
TCM doesn't talk about cortisol directly, but one phrase says chronic stress better than most: "excessive worry quietly burns the heart-blood." Long-term tension, worry, and overthinking drain the "qi and blood" of the heart and spleen — the heart houses the spirit, the spleen governs digestion. When heart-blood runs low, you get heart palpitations, insomnia, and scattered attention; when spleen-qi is weak, digestion goes haywire and you feel wilted.
The Chinese character for "rest" is written with "self" and "heart" — rest means the heart returning to yourself. TCM's core take on stress comes down to one word: gathering. Pull back the attention that keeps spilling outward. Deep breathing, sitting quietly, taking a walk — all of these are acts of "gathering." Breathing is the fastest switch you can reach, because you don't have to wait for any condition — you can do it right now.
Five things that work better than "just relax"
- 5 minutes of "slow breathing" a day: inhale for 4 seconds, exhale for 6 — a longer exhale activates the parasympathetic nervous system. You don't have to wait for the weekend; you can do it right at your desk.
- 10 minutes of morning sun: morning light helps calibrate the cortisol rhythm — a steady rise in the morning means a clean fall at night, and better sleep with it.
- Turn "exercise" into "just moving": brisk walking, stretching, taking the stairs all count. Intensity doesn't matter; regularity does. Under stress, don't chase "training to exhaustion."
- Give your phone a "parking spot": an hour before bed, put the phone in another room and let an alarm clock wake you instead. An information feed that never goes quiet is a hidden driver of chronic stress.
- Leave yourself a "blank space": 10 minutes a day — doing nothing, no scrolling, no podcasts, just sitting or walking. Give your brain a sample of "no task," and it learns how to relax.
Can't get through all five today? That's okay. The point of stress management is to be kind to yourself, not to clock in for performance. Even slowing your pace for five minutes on the way home counts as easing off the brake.
FAQ
If it's mainly long-term fatigue and shallow sleep, you can start with lifestyle changes without rushing to test hormones. But if it comes with obvious abnormal weight, rising blood pressure, or extreme weakness, see a doctor. Cortisol can be tested through saliva, blood, or urine — whether you need it and how it's done is a doctor's call. Don't self-test and self-interpret.
Research shows slow breathing (especially exhales longer than inhales) activates the parasympathetic nervous system and lowers heart rate, and long-term practice helps improve your stress response. It doesn't change the objective stressor, but it changes the "amplitude" of your body's reaction — like turning down the volume of the horn, rather than parking the car in the garage.
There's no such thing as an "anti-stress food," but there is a way of eating that takes the load off the nervous system: regular meals, less refined sugar, a reasonable amount of dark leafy greens (they carry magnesium), and no pushing through on an empty stomach. Under stress, people tend to run on sweets and coffee — that's adding fuel to the horn. Short-term perk, long-term fatigue.
A Note from Bong
Once, when I was picking up medicine with a family member, we waited our turn. He sat in the chair, bouncing his leg, his phone lighting up and going dark again — he said he had messages to answer. I told him: sit out these ten minutes, the sky won't fall. He laughed, but the leg kept bouncing. Stress isn't something "just relaxing" can hold down — it lives in your shoulders, in your jaw, and in that leg that won't stop moving.
My own way of releasing pressure is plain: in the evening I put the herbs back in order and take a couple of laps downstairs. No phone, just walking — sometimes watching the clouds, sometimes the row of ginkgo trees by the building. After ten minutes, I genuinely feel lighter.
Don't turn "de-stressing" into one more item on your to-do list. Today, do just one thing: put the phone down, stand up, walk for ten minutes. I'm going for a walk now — catch you later.
References
- American Psychological Association. "Stress effects on the body." APA
- Zandara M. et al. "The influence of acute stress on memory and attention." PubMed Central
- National Center for Complementary and Integrative Health. "Relaxation Techniques: What You Need To Know." NCCIH
Which "animal" is your stress right now?
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