Astma usually strts in childhood and improves
with time and it is rare after 40.
Food allergies may appear at any time, but symptoms (face flushes, lips swelling, skin itching and eventual hard breathing) appear within an hour after the meal, or in delayed allergy response, within 36 hours (usually the same day or night) after the culprit food, but they cease after few hours - so symptoms in food allergies are never constant, and should be not trigered by exercise.