Exercise-induced Asthma Essay

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Exercise-induced asthma is an acute transient airway narrowing that occurs during and most often after exercise. It is objectively defined as a 10% fall in forced expiratory volume in the first second from baseline that may be measured up to thirty minutes following exercise (M&M). Exercise-induced asthma occurs not only in elite athletes and asthmatics, but it can also be found in non-asthmatics. The stimulation of exercise-induced asthma can range anywhere from inhaling allergens to hyperventilation or intense exercise. The management and prevention of exercise-induced asthma is a series of trials to reduce the effects of prolonged bronchoconstriction. In some cases, exercise-induced asthma is referred to as exercise-induced…show more content…
Mechanics The nose protects the lower airways by filtering, moistening, and heating the inhaled air. However, breathing through the nose alone cannot cover the oxygen demand, when elite athletes exercise, as ventilation through the nose cannot exceed 30 L/min. Therefore, when ventilation exceeds this level through the nose, concomitant ventilation through the mouth automatically appears. The combined breathing can be harmful to the lower airways because they are now exposed to air with allergens, other small particles, and unheated air (M&M). Theories Two main theories have been proposed to explain the bronchoconstriction associated with hyperventilation and airway cooling in the asthmatic patients: the first attributes a predominant role to the vagus nerve, whereas the second emphasises the part played by mediator substance released from mast cells in the airways (EIA & EO). Water loss in the airway triggers exercise-induced asthma through the development of hypertonicity of the liquid at the surface of the airways. As cool and/or dry air is inhaled, heat is transferred away from the airway mucosa to air passing through the bronchial tree. When the inhaled cold air is heated, the saturation with water vapor consequently drops, which results in the evaporation of water from the mucosa, thus cooling of the respiratory tract. The evaporation of water results in
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