Can you really be allergic to exercise? Yes, and it can turn life-threatening

Exercise allergy is a rare condition in which physical activity can trigger a severe reaction, the symptoms of which can be mistaken for routine breathlessness.

In Short

• Exercise-induced anaphylaxis is rare but can become life-threatening without early recognition
• Symptoms include hives, wheezing, dizziness and breathing trouble during workouts
• Food, especially wheat, can trigger attacks when followed by exercise
• Doctors diagnose the condition through history, triggers and supervised testing

For many people, exercise is considered one of the healthiest things they can do. But for a small number of people, physical activity itself can trigger a severe allergic reaction, a little-known condition called exercise-induced anaphylaxis, described as an "exercise allergy."

Though rare, the condition is real and can become life-threatening if not recognised early.

Exercise-induced anaphylaxis (EIA) was first identified in the 1970s and accounts for an estimated 2.3% to 5% of all anaphylaxis cases worldwide.

Researchers describe it as a rare but potentially fatal allergic disorder that is missed or diagnosed late.

MORE THAN JUST FEELING BREATHLESS

Unlike normal tiredness or shortness of breath after a workout, exercise-induced anaphylaxis causes symptoms that resemble a severe allergic reaction.

People initially notice itching, hives, flushing, or swelling of the skin. As the reaction worsens, symptoms can include wheezing, chest tightness, nausea, abdominal cramps, dizziness, a drop in blood pressure and, in severe cases, difficulty breathing or loss of consciousness.

Symptoms usually appear during exercise or within half an hour after physical activity.

Running, jogging, dancing, football, cycling and even activities such as gardening have been linked to attacks. Aerobic exercise appears to be the most common trigger.

WHY DOES IT HAPPEN?

Scientists still do not completely understand why some people develop exercise-induced anaphylaxis.

Current evidence suggests that physical activity activates mast cells, immune cells that release chemicals such as histamine. This triggers an allergic response throughout the body.

In many cases, exercise alone is not enough to cause symptoms. Certain "co-factors" can make reactions more likely.

Food is one of the most common triggers. This condition is known as food-dependent exercise-induced anaphylaxis (FDEIA), where a person tolerates a particular food normally but develops an allergic reaction if they exercise within a few hours of eating it.

Wheat is one of the most frequently implicated foods, although shellfish, nuts, celery, fruits and seafood have also been reported.

Alcohol, aspirin and other painkillers, infections, hot or cold weather, humidity, and hormonal changes may also increase the risk of attacks.

According to a 2022 systematic review involving more than 700 patients, nearly 80% experienced full-blown anaphylaxis accompanied by hives or swelling.

OVERLAPPING SYMPTOMS

Because the symptoms can overlap with asthma, panic attacks, or heat exhaustion, diagnosis can be challenging.

Doctors usually rely heavily on a person's history, looking for patterns between exercise, food intake and other triggers. Allergy tests and supervised exercise challenge tests may sometimes be used to confirm the diagnosis.

Researchers note that there is still no single laboratory test that can definitively diagnose the condition.

CAN PEOPLE WITH EXERCISE ALLERGY STILL WORK OUT?

Fortunately, having exercise-induced anaphylaxis does not mean giving up physical activity altogether.

The key is identifying and avoiding triggers. Patients with food-dependent exercise allergy are advised not to exercise for four to six hours after eating the offending food.

People who have experienced severe reactions are usually prescribed adrenaline auto-injectors and taught how to use them in emergencies. Exercising with a companion and recognising early warning signs can also reduce the risk of serious complications.

Long-term studies suggest that symptoms often become less frequent or stabilise over time, particularly when patients learn to avoid known triggers.

For people who repeatedly develop hives, itching, swelling, wheezing or unexplained breathing difficulties during workouts, the symptoms should not be dismissed as simply being "out of shape."

Sometimes, the body's healthiest habit can unexpectedly trigger one of its most dangerous reactions, making early recognition and prompt treatment crucial.

- Ends