What do we mean by an Asthma

An Asthma is a chronic or long-term lung disease that inflames and narrows the airways. Asthma causes recurring periods of wheezing, a whistling sound when you breathe, chest tightness, shortness of breath, and coughing. The coughing often occurs at night or early in the morning.
Asthma affects people of all ages, but it most often starts during childhood. When the airways react, the muscles around them tighten. This narrows the airways, causing less air to flow into the lungs. The swelling also can worsen, making the airways even narrower. Cells in the airways may make more mucus than normal. Mucus is a sticky, thick liquid that can further narrow your airways.
Bronchial tubes that are chronically inflamed may become overly sensitive to allergens or irritants. The airways may become twitchy and remain in a state of heightened sensitivity. This is called bronchial hyperreactivity. It is likely that there is a spectrum of bronchial hyperreactivity in all individuals. However, it is clear that asthmatics and allergic individuals without apparent asthma have a greater degree of bronchial hyperreactivity than nonasthmatic and nonallergic people.
In sensitive individuals, the bronchial tubes are more likely to swell and constrict when exposed to triggers such as allergens, tobacco smoke, or exercise. Amongst asthmatics, some may have mild bronchial hyperreactivity and no symptoms while others may have severe bronchial hyperreactivity chronic symptoms.