Asthma affects approximately 10% of the nation, and it comes in various forms. Asthma can be triggered by allergens, air pollution, physical activity, and medicines and the causes are typically genetic but can also be influenced by respiratory infections and atopy. When it comes to the diagnosis, your doctor may listen to your breathing along with looking for signs of allergies (wheezing, runny nose, swollen passageways, and allergic skin conditions). It is common to go through bronchoprovocation tests, this measures the airways reaction to certain exposures and is a great way to guide asthma treatment. Other tests may include: allergy testing, chest x-ray or EKG (to determine if a foreign object is increasing these symptoms), and spirometry. Asthma is chronic and the goal is to control the disease, which is to reduce the need for quick relief, maintain normal activity levels, and preventing attacks that could lead to the ER. It is treated with two types of medication: Albuterol (long term) and Ventolin HFA (quick relief) and in other cases cromolyn is used with a nebulizer.
One of the most common types of asthma is exercise-induced bronchoconstriction (EIB). This term is used to describe the increase in airway resistance after exercise. The stimulus is water loss from the humidification of inspired air, causing dehydration of the airways surface during physical activity(Anderson SD, P. Kippelen, 2008). The source of water to humidify the air is the sol layer of airway surface liquid (ASL) lining the epithelium. When the ventilation exceeds a certain point, water will be rapidly replaced on the airway surface, preventing dehydration. There tends to be a rapid increase in airway temperature after exercise in those with asthma compared to normal subjects. The dryer/cooler the air, the greater chance of asthmatic response, this can explain the higher occurrence of EIB in winter sports. There are two theories: Thermal and Osmotic. Thermal presents the idea that EIB is a vascular event leading to vasoconstriction during exercise. Osmotic theory is that the water loss creates an increase in osmolarity in airways, releasing mediators which further causes increased vascular permeability and smooth muscle to contract (S.D. Anderson, P. Kippelen Breathe 2010 7:25-33).
Another common form is nocturnal, symptoms including cough and dyspnea. In a study led by Turner-Warwick (1988), 75% of asthmatics are awakened by symptoms once a week and approximately 40% experience nocturnal symptoms nightly. Lung function fluctuates throughout the day in healthy patients, however asthmatics with nocturnal symptoms experience a significant drop in lung function around 4 am along with the daily fluctuations to be far more pronounced (E. Rand Sutherland, 2005). Although the cause is not entirely clear, increased mucus production, and being exposed to allergens (i.e. dust mites) can contribute to this.