Dehydration affects exercise-induced asthma and anaphylaxis.

Allergies are generally triggered by food, medication, physical exercise, stress, alcohol consumption, and dehydration. There are reports that indicate dehydration affects various kinds of physical allergies. However, there are few studies that have focused on the effects of dehydration on asthma and allergy anaphylaxis. Therefore, we analyzed the effects of dehydration on several kinds of allergy responses and exercise-induced asthma especially during the endurance exercise. PubMed was searched from April to July of 2019 using predefined search terms "dehydration," "exercise," and "allergy responses." Based on the reference search, more than one-hundred articles were identified but eighteen papers met the inclusion criteria and were analyzed for connections among exercise and dehydration, dehydration and exercise-induced asthma, and allergy responses in the main text. Results suggest that dehydration directly impairs stroke volume, cardiac output, and skin blood flow. This results in larger increases in core temperature, heart rate, and stroke volume. Additionally, exercise-induced dehydration reduces airway surface hydration, which results in an amplified brocnchoconstriction. This response to exercise occurs in those who suffer from exercise-induced asthma. Moreover, damage to the gut and impaired gut function relates to increased intestinal permeability after endurance exercise. Endurance exercise changes the immunological profiles to activate antibody-mediated immunity. Also, numerous mast cells and eosinophils were recruited, therefore isotype switching to IgE antibodies occur, this hypersensitivity activates mast cell degranulation. After degranulation, proteases, leukotrienes, prostaglandins, and histamine lead to many kinds of allergy symptoms.