People Can Be Allergic to Exercise

While a brisk jog or a session at the gym is a cornerstone of health for most, for a small number of people it can trigger a terrifying and life-threatening event. This rare condition, known as exercise-induced anaphylaxis (EIA), causes the body's immune system to overreact to physical activity. Instead of a healthy post-workout glow, individuals can suddenly experience hives, swelling of the face and throat, and severe difficulty breathing. In the most serious instances, this can escalate into full anaphylactic shock, a medical emergency where blood pressure plummets and airways constrict.

First formally described in medical literature in 1979, the science behind EIA often points to a fascinating interaction between diet and activity. Many cases are classified as food-dependent, meaning the allergic reaction only occurs when exercise follows the consumption of a specific trigger food, often within a few hours. While the food alone is harmless and the exercise alone is safe, the combination proves dangerous. The most common culprits are wheat and shellfish. The leading theory suggests that exercise increases the permeability of the digestive tract, allowing small amounts of the food allergen to enter the bloodstream, where the immune system then launches its massive, misguided attack.