Asthma is a chronic lung condition. Inflammation, increased mucus, and muscle tightening cause the airways to narrow, and as a result, air can't move through the lungs as well as it should, which makes it difficult to breathe.
For reasons we do not completely understand, asthma is becoming more common each year, especially in children. According to the World Health Organization (WHO), about 300 million people in the world have asthma. Over 3 million Canadians suffer from this condition.