Have you ever joked “I’m just allergic to exercise?” after a lackluster workout—or even used it as an excuse to get out of going to the gym? Chances are, you’re just a little out of shape or tired. But some people really are allergic—at least, they exhibit symptoms after or during exercise that are identical to symptoms of someone experiencing an allergic attack. And it’s no joke. It can be very serious—and in a few tragic cases, even fatal. If you’re concerned that you might be predisposed to exercise-induced anaphylaxis, it’s time to examine your symptoms and reactions a little more closely. Your doctor may also want to conduct an exercise challenge test on a treadmill or stationery bicycle. What it looks like According to the Journal of Allergy and Clinical Immunology, there are four basic stages of an attack of exercise-induced anaphylaxis: Prodromal Early Full established Late The prodromal stage marks the very beginning, with the appearance of the first symptom. You might experience a growing itching sensation on your skin and feel the urge to scratch. You may also notice an uncomfortable sensation of warmth and fatigue. During the second phase, you might then develop hives, a condition known as urticaria. The third, or full established, phase is when the airways begin to swell. Soon you start to experience choking and a high-pitched wheezing sound called stridor which accompanies harsh breathing. You might even experience certain gastrointestinal symptoms like nausea and vomiting. The late phase is when you develop a splitting headache that could last for a couple of days. If you experience these symptoms, call for medical help as soon as you notice them. For minor incidents, an antihistamine may help, but in a more serious event, you will likely need epinephrine. If you’ve already experienced one episode, you should carry an emergency epinephrine injector—think EpiPen or Twinject. And you may want to start wearing a medical alert bracelet. How to prevent an attack Watch for symptoms. Some research suggests you can ward off an attack if you can identify it during the very early stage and address the problem. Don’t keep going. Stop exercising and rest. Avoid trigger foods. It’s not very common, but certain foods and medicines can trigger an episode of anaphylaxis in some people when they exercise. Common food culprits include shellfish, peanuts, tomatoes and wheat. By itself, however the food doesn’t cause the anaphylaxis, but the exact mechanisms and prevalence haven’t been well established yet. You will have to learn how long to wait before exercising if you’ve consumed one of these “triggers.” Additionally, the American Academy of Family Physicians (AAFP) suggests that you may be better off waiting four to six hours after eating before exercising, even if you don’t have a particular trigger food. Skip the OTC painkillers. The AAFP also notes that non-steroidal anti-inflammatory drugs (NSAIDs) and aspirin seem to trigger anaphylaxis in some people during exercise. Take an antihistamine. Certain antihistamines may help you ward off an attack. Talk to your doctor before you go this route, however, to get a recommendation, as certain meds have fewer side effects than others. Watch the weather. If it’s really cold or really hot outside, you may want to curtail your workout. Exercise with a partner. Exercising with a buddy has multiple benefits, including a second set of eyes to watch for symptoms. Find a trusted friend or partner whom you can educate about exercise-induced anaphylaxis and how to address it, including administering basic life support and using the EpiPen.