Several medical conditions produce symptoms nearly identical to a panic attack, including a racing heart, sweating, trembling, chest pain, and a feeling of dread. Some of these are harmless, while others require urgent treatment. The overlap is so convincing that misdiagnosis goes both directions: people with genuine panic disorder get unnecessary cardiac workups, and people with heart rhythm problems or hormone imbalances spend years being told they “just have anxiety.”
If your episodes have features that don’t quite fit the textbook panic attack, or if standard anxiety treatment isn’t helping, one of the conditions below may be the real cause.
Heart Rhythm Problems
Supraventricular tachycardia (SVT) is one of the most commonly missed panic mimics. It’s an electrical malfunction in the heart that causes sudden, rapid heartbeats, often accompanied by chest tightness, shortness of breath, lightheadedness, and a surge of fear. The experience feels almost indistinguishable from a panic attack, and many people with SVT are initially diagnosed with panic disorder.
The key difference is in the heart rate itself. During a panic attack, your heart rate typically rises to 100 to 130 beats per minute. SVT can push the heart to 150, 170, or even above 200 beats per minute. One published case involved a woman whose episodes had been treated as panic attacks for years before an ECG during a prolonged episode caught a heart rate of 217 BPM with a specific abnormal rhythm. Her earlier episodes had lasted a few minutes to an hour and resolved on their own, making them easy to dismiss as anxiety. The episode that finally led to diagnosis lasted five hours.
A clue that points toward SVT: the racing heart starts and stops abruptly, like flipping a switch. Panic attacks tend to build gradually and taper off. If you can feel your heart suddenly snap into a fast, regular rhythm and then abruptly return to normal, that pattern warrants a heart evaluation. The catch is that a standard ECG done in a doctor’s office only captures what’s happening at that moment, so you may need a portable heart monitor worn over days or weeks to catch an episode in progress.
Heart Attack
The overlap between a heart attack and a panic attack causes real confusion in emergency rooms. Both can produce chest pain, shortness of breath, sweating, nausea, and a sense that something is terribly wrong. But heart attack pain has distinct qualities: it typically feels like pressure or squeezing in the center of the chest, lasts more than a few minutes, and often radiates into the arm, neck, or jaw. Panic attack chest pain is more commonly sharp or stabbing and stays localized.
If you experience central chest pressure that spreads to your arm or jaw, treat it as a heart attack until proven otherwise.
Blood Clots in the Lungs
A pulmonary embolism (a blood clot that travels to the lungs) can trigger sudden shortness of breath, chest pain, a racing heart, and intense anxiety. The body’s response to reduced oxygen can itself induce hyperventilation and panic, creating a feedback loop that makes the whole episode look psychiatric.
The chest pain from a pulmonary embolism has a specific character: sharp and stabbing, usually on one side of the chest, and it gets worse when you breathe in deeply, cough, or twist your torso. That pleuritic quality is different from the diffuse tightness most people feel during a panic attack. Oxygen levels drop in roughly 60% of cases, though they can remain normal in smaller clots. Risk factors include recent surgery, long flights or car rides, use of hormonal birth control, or a history of blood clots.
Overactive Thyroid
Hyperthyroidism floods your body with thyroid hormones that speed up nearly every system. The result is a racing heart, trembling hands, sweating, weight loss, difficulty sleeping, restlessness, and trouble concentrating. Many of these overlap directly with generalized anxiety and panic, and misdiagnosis is common.
What sets hyperthyroidism apart is that the symptoms don’t come in discrete episodes and then disappear. You feel revved up most of the time. Other distinguishing signs include unexplained weight loss despite a normal or increased appetite, heat intolerance (feeling uncomfortably warm when others are fine), changes in your menstrual cycle, and fine tremors visible in your outstretched hands. In one documented case, a patient was treated for anxiety disorder before blood work revealed extremely low levels of thyroid-stimulating hormone (TSH) with elevated thyroid hormones, confirming hyperthyroidism as the true cause. A simple blood test measuring TSH is the standard screening tool, and it’s one of the first things a doctor should check when panic-like symptoms don’t respond to anxiety treatment.
Adrenal Tumors
Pheochromocytoma is a rare but dramatic panic mimic. It’s a tumor on the adrenal gland that releases bursts of adrenaline and related hormones, triggering sudden episodes of pounding heartbeat, profuse sweating, headache, tremor, and overwhelming fear. The classic triad is episodic headaches (present in about 90% of cases), sweating (60 to 70%), and palpitations (70%). These surges can last minutes to hours and feel exactly like severe panic attacks.
The distinguishing feature is blood pressure. Roughly 95% of people with pheochromocytoma have sustained or episodic high blood pressure, sometimes dramatically high. If your “panic attacks” come with a flushed or pale face, a pounding headache, and your blood pressure reads well above normal during an episode, this rare tumor is worth investigating. Diagnosis involves urine and blood tests that measure adrenaline-related hormones.
Low Blood Sugar
When your blood glucose drops too low, your body releases a surge of adrenaline to compensate. That adrenaline rush causes shakiness, sweating, heart palpitations, anxiety, nausea, and difficulty concentrating, a combination that closely mirrors a panic attack. This is called reactive hypoglycemia when it happens after meals, particularly meals high in refined carbohydrates and sugar. The spike in blood sugar triggers a large insulin response, which then overshoots and drives blood sugar too low.
The timing is a useful clue. If your panic-like episodes tend to occur two to four hours after eating (especially after sugary or starchy meals), or if they improve quickly when you eat something, blood sugar may be involved. Symptoms like muscle weakness, headache, and mental fogginess alongside the anxiety point more toward low blood sugar than true panic. In some cases, shifting to a diet with more protein, fat, and fiber while reducing refined carbohydrates has resolved both the hypoglycemic episodes and the anxiety symptoms together.
Focal Seizures
Seizures originating in the temporal lobe of the brain can produce sudden waves of intense fear, a sense of unreality, changes in heart rate and skin color, sweating, and nausea. These focal seizures don’t always involve the dramatic convulsions people associate with epilepsy. They can look and feel almost exactly like a panic attack.
Several features help separate the two. Focal seizures tend to be shorter, typically lasting one to four minutes, while panic attacks commonly last 5 to 30 minutes. Seizures may begin with unusual sensory experiences like tingling that spreads through the body, strange tastes or smells, or a powerful sense of déjà vu. A witness might notice repetitive involuntary movements during an episode, like lip smacking or repeated swallowing, which don’t occur in panic attacks. Panic disorder rarely begins after age 45, so a first “panic attack” in someone over 45 should raise suspicion for a neurological cause. Diagnosis typically requires an EEG, ideally one that captures an actual episode.
Vestibular and Inner Ear Problems
Dizziness and lightheadedness are common in panic attacks, but they’re also hallmark symptoms of vestibular disorders affecting the inner ear and balance system. Conditions like vestibular migraine and benign paroxysmal positional vertigo (BPPV) can produce episodes of dizziness, nausea, and disorientation that trigger genuine anxiety, creating a picture that looks like panic.
The type of dizziness matters. Panic attacks more often cause lightheadedness or a floating sensation. Vestibular problems tend to produce true vertigo, a feeling that the room is spinning or tilting. If your dizziness is triggered or worsened by head movements, rolling over in bed, or looking up, a vestibular cause is more likely. Chronic unexplained dizziness lasting three months or more, particularly between episodes, warrants evaluation by a specialist familiar with inner ear disorders.
Low Calcium Levels
Hypocalcemia, or abnormally low blood calcium, causes a condition called tetany: heightened nerve and muscle irritability that produces tingling around the mouth, numbness and pins-and-needles in the hands and feet, muscle cramps, and in severe cases, involuntary spasms of the hands and feet. Combined with the anxiety and racing heart that low calcium also causes, mild tetany can be mistaken for a panic attack with hyperventilation.
The distinguishing symptoms are the muscle-related ones. Persistent tingling around your lips, cramping in your hands that pulls your fingers into awkward positions, or muscle twitching that you can’t control suggest a calcium problem rather than anxiety. Causes include vitamin D deficiency, parathyroid gland dysfunction, and certain medications. A basic blood panel can identify it.
How Doctors Sort It Out
When you describe panic-like episodes to a doctor, the standard workup typically includes blood tests checking thyroid function and blood sugar, along with an electrocardiogram to evaluate heart rhythm. These three tests alone can screen for several of the most common mimics. Depending on your specific symptoms, additional testing might include calcium and electrolyte levels, urine tests for adrenal hormones, a Holter monitor for heart rhythm, or referral for an EEG or vestibular evaluation.
The most important thing you can do is describe your episodes in detail: when they happen, how long they last, what triggers them, and whether any symptoms seem unusual for “just anxiety.” Features worth mentioning include a heart rate that feels impossibly fast, episodes tied to meals, dizziness with head movement, tingling that follows a pattern, unexplained weight loss, or blood pressure readings that spike during attacks. These details help your doctor decide which conditions to test for beyond the standard screening.