Asthma is associated with mast cells, eosinophils, and T lymphocytes. Mast cells are the allergy-causing cells that release chemicals like histamine. Histamine is the substance that causes nasal stuffiness and dripping in a cold or hay fever, constriction of airways in asthma, and itchy areas in a skin allergy. Eosinophils are a type of white blood cell associated with allergic disease. T lymphocytes are also white blood cells associated with allergy, and inflammation.These cells, along with other inflammatory cells, are involved in the development of airway inflammation in asthma that contributes to the airway hyperresponsiveness, airflow limitation, respiratory symptoms, and chronic disease. In certain individuals, the inflammation results in the feelings of chest tightness and breathlessness that's felt often at night (nocturnal asthma) or in the early morning hours. Others only feel symptoms when they exercise (called exercise-induced asthma). Because of the inflammation, the airway hyperresponsiveness occurs as a result of specific triggers.For many asthma sufferers, timing of these symptoms is closely related to physical activity. And, some otherwise healthy people can develop asthma symptoms only when exercising. This is called exercise-induced bronchoconstriction (EIB), or exercise-induced asthma (EIA). Staying active is an important way to stay healthy, so asthma shouldn't keep people on the sidelines. The physician can develop a management plan to keep the patients symptoms under control before, during and after physical activity.People with a family history of allergies or asthma are more prone to developing asthma. Many people with asthma also have allergies. This is called allergic asthma.Asthma is a long-term lung condition. People with asthma have sensitive airways in their lungs which react to triggers, causing a 'flare-up'. In a flare-up, the muscles around the airway squeeze tight, the airways swell and become narrow and there is more mucus. These things make it harder to breathe.An asthma flare-up can come on slowly (over hours, days or even weeks) or very quickly (over minutes). A sudden or severe asthma flare-up is sometimes called an asthma attack.One in nine people in Australia has asthma. It affects people of all ages. Some people get asthma when they are young; others when they are older.