Many of us joke about being “allergic” to exercise. But for roughly one in a thousand people, exercise-induced anaphylaxis (EIA) is no laughing matter. For those with this rare allergy, physical activity doesn’t just make them sweat, it can trigger nausea, vomiting, hives, shortness of breath, and even dangerous drops in blood pressure.
The condition was first identified in the late 1970s, when doctors encountered patients who suffered severe anaphylactic reactions after exercising, especially if the activity took place within a few hours of eating certain foods, such as shellfish.
The discovery baffled the medical community; after all, exercise is usually associated with health, not a potential cause of death.
How Rare Is It, and Who Can Get It?
By the numbers, EIA is extremely rare. A population study of Japanese adolescents aged 13–15 found a prevalence of just 0.048%. Globally, estimates suggest fewer than 1 case per 1,000 people. Still, analyses indicate that 2–5% of all anaphylaxis cases reported in hospitals are linked to physical activity.
EIA knows no age or gender boundaries, though clinical reports show a slightly higher tendency in women and younger, physically active individuals. It also appears more frequently among those with a history of allergies or atopic conditions such as asthma or allergic rhinitis.
Symptoms: From Itch to Collapse
For some sufferers, symptoms start subtly—itchy palms, skin redness, or an unusual warm sensation. Then the reaction escalates: hives spreading across the body, followed by nausea, vomiting, and abdominal pain.
Within minutes, this can progress to breathing difficulties caused by airway swelling, dizziness from a sharp drop in blood pressure, and even collapse. In certain cases, patients experience lingering effects such as headaches and extreme fatigue that can last up to three days after the attack.
When Food and Exercise Become a Dangerous Duo
The most common form is food-dependent exercise-induced anaphylaxis (FDEIA), an allergy that only manifests if exercise takes place within a few hours of eating a trigger food. Wheat—particularly the omega-5 gliadin protein—is one of the most frequently implicated culprits. Other reported triggers include shellfish, peanuts, tomatoes, eggs, milk, corn, fruits, and celery.
Beyond food, taking nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin or ibuprofen before exercise can significantly increase the risk of an attack. Environmental factors—extreme temperatures, high pollen counts, viral infections, emotional stress, or even the menstrual cycle—can act as “additional triggers,” making the body more reactive.
The Mystery Behind the Mechanism
Why does the body react this way? Scientists are still piecing together the puzzle.
Doctors and researchers suspect a combination of factors prompts the body to release chemicals such as histamine, the culprit behind itching, swelling, and the dangerous drop in blood pressure during allergic reactions.
Triggers vary from person to person, not just in type, but also in the intensity and duration of exercise required to provoke a reaction. Aerobic activities such as running or cycling are the most common offenders. For some, exercise alone can spark an attack; however, symptoms more often appear when another factor—such as food or medication—is involved.
As for how long this condition lasts, that remains unclear. Whether it can resolve on its own or is a lifelong issue is still an open question in the medical community.
A Diagnosis That’s Not Always Straightforward
Diagnosing EIA requires a detailed clinical history. Physicians will ask about the type of exercise performed, the timing of symptoms, any food or medication consumed beforehand, and environmental conditions during the episode. Skin prick tests or allergy blood tests may help, but in FDEIA cases, they often return negative results.
Some allergy clinics in the UK and Japan even use a controlled “exercise challenge test” to confirm the diagnosis, conducted with full resuscitation equipment on standby, given the high risk of severe reactions.
Guidelines from Official Bodies
While few national health agencies have issued public guidelines specifically for EIA, organizations such as the UK’s Anaphylaxis Campaign and Australia’s Allergy Facts have published official fact sheets covering its definition, mechanism, risk factors, and recommended first-aid steps.
They emphasize that awareness is crucial—particularly for athletes, students, and regular exercisers with a history of food allergies or asthma.
Reference:
- https://link.springer.com/article/10.1007/s11882-024-01176-4?
- https://pmc.ncbi.nlm.nih.gov/articles/PMC3483190/?
- https://www.mdpi.com/2075-4663/13/7/215?
- https://emedicine.medscape.com/article/886641-overview?
- https://www.anaphylaxis.org.uk/fact-sheet/exercise-induced-anaphylaxis/?
- https://pmc.ncbi.nlm.nih.gov/articles/PMC5257219/?
- https://allergyfacts.org.au/exercise-induced-anaphylaxis/?
