Asthma is a chronic respiratory disease that constricts and inflames the airways. This causes excess mucus to form in the lungs and a narrowing of the airways that causes the symptoms of wheezing, shortness or breath, coughing, and tightness in the chest. A severe constriction of the airways, often caused by allergens or excessive exercise, is called an asthma attack.

One way that people with asthma can detect if they are going to have an asthma attack is by measuring their peak expiratory flow or peak flow for short. Peak flow measures how fast a person breathes out when that person tries his or her hardest. Basically, it tells a person how well his or her lungs and airways are working. This is often measured with a peak flow meter, a small analog or digital device that a person breathes into.

Peak flow assists people with asthma by telling them that an asthma attack is likely to occur. If a person's peak flow is low then the person's asthma is bothering him or her and the likelihood of an attack increases. This may be caused by triggers that increase the asthma symptoms such as pollen, cigarette smoke, or dust. A peak flow meter can help a person detect these triggers and steps can be made to remove the person from the triggers.

Measuring peak flow is also often used to access if certain asthma medications are helping a person or not. If a person's peak flow measurement is low then it may be a cue to change or increase medications to alleviate the asthma symptoms and prevent the likelihood of an asthma attack. If a peak flow is very high, then it may be possible to reduce the dosage of medications. No changes to medications should be made without the consultation of the doctor.

Asthma is a very serious disease that affects millions of children and adults worldwide. If you or someone you know has asthma, you owe it to yourself to learn all that you can about this chronic respiratory disease.