The rest of this page explains what tends to set an adrenal crisis off, which blood markers help explain the picture, what those markers can and cannot show, and the point at which reading should stop and care should start.
An adrenal crisis starts when the body cannot raise cortisol to meet a sudden demand, and the demand is almost always something ordinary rather than exotic. The everyday events that sit behind it most often are a stomach bug with vomiting and diarrhoea, a fever or chest infection, heavy fluid loss from heat or hard training, an injury, a dental or surgical procedure, a stretch of intense physical or emotional strain, and an interruption in some medicines (ask your prescriber).
Research suggests that infection, particularly gastrointestinal illness with vomiting and diarrhoea, is among the most common triggers of an adrenal crisis 1. The trigger is rarely the whole story, though. What sits underneath it is adrenal insufficiency, a state in which the adrenal glands cannot produce enough cortisol for what the body is asking of them 2.
That underlying state arrives by a few different routes, and the route matters for which blood markers shift.
It is worth saying the obvious thing plainly. Most tiredness, light headedness, nausea and salt craving has an ordinary explanation. Short sleep, under eating, dehydration, alcohol the night before, a heavy training block, a viral illness still clearing, a long stretch of stress and the first weeks of a new life stage all produce overlapping symptoms. An adrenal crisis is different in speed and severity. It builds over hours to a couple of days, it does not improve with rest, and the person usually looks unwell to everyone around them.
The pattern that most often precedes it is a gradual one. Research suggests that the symptoms of adrenal insufficiency are frequently non specific in the months before diagnosis, including fatigue, weight loss, low blood pressure on standing and abdominal discomfort, which is part of why the diagnosis is often delayed 5. Skin darkening, including on scars, knuckles and gums, can appear in primary adrenal insufficiency and not in the secondary form 3.
Three blood markers carry most of the weight when adrenal function is being evaluated, and they are cortisol, sodium and potassium. None of them diagnoses anything alone. Each one narrows the question a clinician is asking.
| Marker | Why it is linked to this symptom | What a result can and cannot tell you |
|---|---|---|
| Cortisol | Cortisol is the hormone that holds blood pressure, blood sugar and blood vessel tone steady when the body is stressed, so a shortfall produces weakness, nausea and faintness | It can show whether cortisol is low at a time of day when it should be high. It cannot by itself separate adrenal from pituitary causes, and a single value is not a diagnosis |
| Sodium | A low sodium level is one of the most frequent laboratory findings when cortisol is deficient, because water handling and salt retention both depend on adrenal hormones | It can flag a shift worth explaining. It cannot tell you why sodium is low, because fluid losses, fluid overload, kidney, heart and liver conditions and some medicines do the same thing |
| Potassium | Potassium tends to rise when aldosterone is deficient, which happens in primary adrenal insufficiency and usually not in the secondary form | It can help point toward the adrenal glands rather than the pituitary. It cannot stand alone, because kidney function and sample handling both change the number |
Typical lab reference ranges look roughly like this.
| Marker | Typical lab reference range | Units |
|---|---|---|
| Cortisol, morning serum sample | 6 to 23 | µg/dL |
| Sodium | 135 to 145 | mmol/L |
| Potassium | 3.5 to 5.2 | mmol/L |
These are typical lab reference ranges and they vary by lab, assay, age and sex. Always read your own result against the range printed on your own report.
Yes, low cortisol is one possible reason for weakness, nausea, abdominal pain, faintness on standing and confusion, because cortisol is the hormone that supports blood pressure, blood sugar and the body's response to physical stress. When the demand rises and cortisol does not rise with it, blood pressure falls, the gut becomes irritable, blood sugar can drop and thinking becomes foggy. That combination arriving quickly is what makes an adrenal crisis a medical emergency rather than a slow decline 1.
Cortisol is usually measured in the morning for a reason. Cortisol follows a daily rhythm, peaking shortly after waking and falling through the day, so an afternoon sample is far harder to interpret. Research suggests that a morning serum cortisol measurement is the standard first step when adrenal insufficiency is suspected, with a stimulation test used when the baseline value sits in an unclear middle zone 6. In an acute emergency, samples are taken in hospital and care is not delayed while results return 1.
Plenty of ordinary things move the cortisol number without any adrenal problem at all. Sleep timing and shift work shift the whole rhythm. Acute illness, pain and surgery raise it sharply. Anxiety about the blood draw itself can lift it. A low morning value is a reason to ask a careful next question, not a conclusion.
Sodium matters because it is one of the most common laboratory signals that cortisol and aldosterone are running short. Studies indicate that a low sodium level is among the most frequent biochemical findings in adrenal insufficiency, reflecting both impaired free water handling and, in the primary form, salt and volume loss through the kidneys 4. That volume loss is also why blood pressure can drop so hard during a crisis 1.
Sodium is a marker that drifts for many reasons, which is exactly why it is useful alongside cortisol rather than instead of it. A low result can follow a long vomiting illness, heavy diarrhoea, drinking large volumes of plain water during endurance exercise, heart, liver or kidney conditions, or an effect of some medicines that your prescriber can explain. A high result usually points toward not enough fluid rather than toward the adrenal glands.
The useful way to read it is in sequence. The observation is a sodium value outside the printed range. The possible meaning is a shift in fluid balance, salt handling or hormone signalling, and adrenal insufficiency is one candidate among several. The next step is a conversation with a clinician who can see the sodium, the potassium, the kidney markers and the clinical picture at the same time. A sodium result that is well outside the standard range is worth discussing with a clinician promptly rather than at the next convenient appointment.
Potassium adds a clue about which part of the system is failing. In primary adrenal insufficiency the adrenal glands lose aldosterone production as well as cortisol production, and aldosterone is the hormone that normally helps the kidneys hold salt and release potassium, so potassium can climb while sodium falls 7. In secondary adrenal insufficiency, where the pituitary signal is the problem, aldosterone production is largely preserved, so a rising potassium is much less typical 3.
Potassium is also one of the easiest markers to misread, because the sample itself can change the number. A difficult draw, a clenched fist, a tight tourniquet or a delay before the tube reaches the analyser can all release potassium from blood cells and produce a falsely high reading. Kidney function changes it. Some medicines change it, and your prescriber is the right person to ask about yours. Severe diarrhoea tends to push it the other way.
So a single raised potassium is a reason to repeat the test carefully, not a verdict. A raised potassium alongside a low sodium, low blood pressure and a person who feels profoundly unwell is a different situation entirely, and that combination belongs in urgent care rather than in a follow up appointment 1.
A normal panel can miss a great deal, and this is the honest limit of blood testing in this area. Timing is the first gap. Cortisol is only interpretable against the time of day it was drawn, and a value taken in the afternoon can look unremarkable while a morning value would have raised a question 6. Partial or early adrenal insufficiency is the second gap, because baseline values can sit inside the reference range until the body is put under stress, which is why a stimulation test exists at all 5.
Electrolytes are an imperfect safety net too. Sodium and potassium can both read normal in the secondary form, and normal electrolytes never rule out a cortisol problem 3.
Then there is everything a blood test was never designed to see. No panel shows how little you slept this month, how much you have been under eating, how hard your training block has been, whether you are dehydrated, whether you have been drinking more than usual, whether a panic response is driving the dizziness, whether an inner ear problem is behind the unsteadiness, or whether a recent viral illness is still working its way out. Those explanations are common and a normal panel does not exclude them. It simply moves the conversation somewhere else.
The practical conclusion is unglamorous. Blood markers narrow the field, they do not close it, and the pattern across several markers plus the story of how symptoms appeared is what a clinician actually works from.
Some of this cannot wait, so here is the plain version. Call 911 or your local emergency number for severe weakness or collapse, repeated vomiting or diarrhoea with no ability to keep fluids down, a blood pressure that will not hold or fainting, confusion, drowsiness that is hard to rouse, or sudden severe pain in the abdomen, lower back or legs, especially when any of these follow an illness or injury. These are the features that describe an adrenal crisis, and it is managed as an emergency with hospital care 1.
In people with known adrenal insufficiency, contact the prescribing clinician promptly at the start of any vomiting illness, fever or injury rather than waiting to see how it goes, because that is the window in which a crisis is usually prevented 2. Treatment decisions belong to a licensed provider.
Book a prompt, non emergency appointment for a pattern that is building rather than crashing. That includes unexplained weight loss with ongoing fatigue, repeated light headedness on standing, persistent nausea or abdominal pain, a strong new craving for salt, or new darkening of the skin on scars, knuckles, palm creases or gums. None of these means you have a particular condition, and none of them should be ignored either.
If you are having thoughts of self-harm, call or text 988 (US) or your local emergency number now.
The FitScript Essential panel includes cortisol, sodium and potassium alongside the kidney, metabolic and blood count markers that give those three numbers context, which matters because no single one of them answers a question on its own. The membership covers 150+ biomarkers tested per year, so changes can be followed over time rather than judged from one snapshot.
Atlas, FitScript's AI health advisor, explains what each result shows in plain language, including which values sit outside the standard range, which ones are likely to be suboptimal rather than alarming, and which ones are worth raising with a clinician promptly. A licensed clinician decides on any next step, including whether further adrenal testing is appropriate for you, and treatment decisions belong to a licensed provider.
This page is educational and is not medical advice. Discuss your own results and any treatment with a clinician or licensed provider who can see your full history.
If you want to go deeper, the overview of adrenal function tests explains how cortisol testing is actually sequenced, what is the hpa axis covers the brain to adrenal signalling loop that sits behind these markers, and addisons vs cushings walks through how too little and too much cortisol differ in presentation.
An adrenal crisis is caused by a sudden shortfall of cortisol when the body needs more of it. The usual triggers are an infection or stomach bug with vomiting and diarrhoea, a fever, dehydration, an injury, surgery or a dental procedure, and an interruption in some medicines. Ask your prescriber about any medicine you take.
The same ordinary events cause it, because the adrenal glands cannot increase cortisol when demand rises. Illness with vomiting or diarrhoea, fever, injury, surgery and severe physical strain are the usual precipitants, along with any gap in prescribed medicines. Contact your prescribing clinician promptly at the start of an illness rather than waiting.
Adrenal insufficiency has three main routes. The adrenal glands themselves can be damaged, which is the primary form. The pituitary gland can fail to send its signal, which is the secondary form. The body's own cortisol production can also be suppressed after long term use of some prescribed medicines, so ask your prescriber.
The features that build before a crisis are often vague, including ongoing fatigue, unexplained weight loss, nausea or abdominal discomfort, light headedness on standing, and a new craving for salt. Darkening of the skin on scars, knuckles or gums can appear in the primary form. None of these is a diagnosis, and all are worth raising with a clinician.
Cortisol, sodium and potassium are the core markers, usually read alongside kidney and metabolic results. Cortisol is normally drawn in the morning because the hormone follows a daily rhythm. When the baseline value is unclear, a clinician may arrange a stimulation test done under supervision to see how the glands respond.
No. A cortisol value only means something when read against the time of day it was taken, so an afternoon sample can look unremarkable. Early or partial insufficiency can also sit inside the reference range until the body is stressed. A clinician decides whether further testing is appropriate for you.
Because the pattern between them is more informative than either number alone. A low sodium with a raised potassium points toward the adrenal glands themselves, while the pituitary form usually leaves potassium normal. Both markers also move for everyday reasons such as fluid loss, kidney function and how the sample was taken.
No, they are not the same. Adrenal crisis is a recognised medical emergency involving a sudden cortisol shortfall with severe weakness, vomiting, very low blood pressure or confusion, and it needs emergency care. Persistent tiredness has many ordinary explanations, and testing plus a clinician's interpretation is the way to sort them out.