Everyone gets anxious from time to time, and usually the cause is easy to pinpoint, whether it's a stressful job, a strained relationship, or money worries. But sometimes anxiety can be a warning sign of an underlying medical problem.

“A sudden, unexplained sense of anxiety could be a signal of something amiss in the body,” says cardiologist Dr Sarah Saaman. While you might be suffering from an anxiety disorder (which is serious in its own right), your symptoms could also be masking another ailment: Researchers recently published a “partial listing” of nearly 50 illnesses that may present as anxiety.

“It may not be a patient’s main symptom, but anxiety can still be an important tip-off,” says Dr Donnica Moore. Here’s the scoop on six conditions where anxiety can act as heads-up—but don't let this add to your anxiety! You could very well simply have chronic anxiety and nothing more—but it may be worth getting tested for these issues just in case.

Overactive thyroid

When a patient with no history of anxiety issues starts complaining of feeling anxious, "hyperthyroidism is one of the first things I'd rule out," says Moore. A condition in which the thyroid gland makes excessive amounts of thyroid hormone, hyperthyroidism increases your metabolic rate, which can lead to symptoms like a rapid heart rate, weight loss, and anxiety. The problem is generally easy to diagnose via a simple blood test to check the level of thyroid hormones. If you have it, you'll probably need to treat it with radioactive iodine. 

Hyperthyroidism is much more common in women, especially those over age 35; incidence also spikes again after age 60 (in both men and women). One caveat: Many symptoms of hyperthyroidism overlap with perimenopause and menopause, which can make it more difficult to suss out, says Moore. But it’s important to get the right diagnosis, since left untreated, an overactive thyroid can cause complications like heart disorders and brittle bones.

Heart disease

“It’s rare for anxiety to be the only symptom of heart disease, but when combined with unexpected shortness of breath with exertion or stress, or with excessive fatigue, it should prompt an evaluation with your physician,” says Samaan, who notes that severe symptoms warrant a visit to the emergency room. Studies confirm the link between anxiety and heart issues: When investigators asked women who suffered a heart attack about which symptoms they experienced in the month leading up to it, 35% reported feeling more anxious, stressed, and keyed up than usual.

Many of the women in the study also reported unusual fatigue (experienced by 70%), sleep disturbance (48%), shortness of breath (42%), and indigestion (39%). Interestingly, fewer than 30% of women reported chest discomfort leading up to their cardiac event—and 43% didn’t even experience it during their heart attack. 


Anaemia occurs when you don’t have enough red blood cells or when they don’t function properly. Since red blood cells carry oxygen, a shortage means your body can’t transport oxygen effectively to where it needs to go. That may cause symptoms like shortness of breath and a fast or irregular heartbeat, which can make you feel like you’re in fight-or-flight mode. 

“When someone is significantly anaemic, the pulse may increase in order to circulate the available blood cells more rapidly,” explains Samaan. “This is the body’s natural way of coping, but the faster heart rate may create a sense of anxiety.”

Women who are menstruating or pregnant and people with chronic medical conditions—particularly rheumatoid arthritis or other autoimmune diseases, kidney disease, cancer, liver disease, thyroid disease and inflammatory bowel disease—are most prone to developing anemia. And, the risk increases with age. The most common form of anaemia, iron-deficiency anemia, happens when you don’t have enough iron in your blood. Eating more iron-rich foods is one easy way to pump up the body’s iron stores.

Nutritional deficiencies

They’re rarely a doctor’s first thought when treating someone with anxiety, but nutritional deficiencies can trigger psychiatric symptoms, says Moore. Take zinc: While too little of this mineral is often linked to depression, a number of studies have also found that a zinc deficiency can lead to related symptoms, including anxiety. 

The average adult woman needs 8 mg of zinc a day (men require 11 mg), and like most vitamins and minerals, zinc can’t be made by the body. Since plants don’t contain as much zinc as animal proteins, zinc deficiency is common among vegetarians. People over 60 and those under a lot of stress are also prone to it. 

Coming up short on B12 can also cause anxiety, along with depression. That’s because this vitamin is needed to create neurotransmitters that govern mood. Most adults need 2.4 micrograms a day, but some people (like vegetarians) don’t consume enough. Another factor is that your body becomes less able to absorb B12 from food as you get older. That likely explains why up to 20% of adults over age 50 have at least a borderline deficiency.

If you suspect you’re low on B12 or zinc, ask your doctor to run a blood test to check your levels.


Some of the symptoms of COVID-19, particularly with breathing rapidly or shortness of breath, feeling weak or tired, and gastrointestinal issues are similar to anxiety.

One clue that your shortness of breath may be due to COVID-19 instead of anxiety? It gets worse when you exert yourself, says Dr Iahn Gonsenhauser. “As you increase your activity, you find your shortness of breath worsens and you have a hard time doing things that are typically easy for you, like walking up a flight of stairs,” he says. “Generally, that’s not the case with anxiety-related shortness of breath.”

Even during a panic attack, you can force yourself to breathe, even if it feels impossible for a bit. With COVID-19, difficulty breathing is out of your control.

Other symptoms of general anxiety or a panic attack, like chest pain, a racing heart, and dizziness are usually short-lived, and often alleviate after 15 to 20 minutes, says professor of psychiatry Dr Gail Saltz. On the flip side, coronavirus symptoms tend to linger for days to weeks, Dr Gonsenhauser says.

If you find yourself breathing rapidly, feeling unusually tired or having gastrointestinal issues, it's worth getting a COVID test just in case. 

Pancreatic cancer

Anxiety seems to be a harbinger of pancreatic cancer, one of the top five cancer killers in both men and women. As one study reported, as many as half of people who ended up being diagnosed with the disease experienced symptoms of depression and anxiety beforehand, though it's unclear why. There have also been two published cases of people having panic attacks prior to receiving their diagnosis. 

Here's the good news: Pancreatic cancer is pretty rare; the average lifetime risk for both men and women is about 1 in 65. The bad news is that it’s a difficult cancer to diagnose early, so survival rates are low. The pancreas is deep inside the body, so early tumours can’t be seen or felt during routine exams. And the initial symptoms—including jaundice (yellowing of the skin and eyes), weight loss, fatigue, malaise, nausea and back pain—are often subtle and come on gradually.

If you notice any symptoms, with or without anxiety, be sure to see your doctor.

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