There are two types of β-agonists, long- and short-acting. They are both inhaled and given by aerosol delivery devices.
Long-lasting β-agonists are often given in a combination with corticosteroids to treat asthma. Short-acting β-agonists are used to treat exercise-induced asthma,
 and for asthma patients to get a quick relief of symptoms. They are taken 10–15 minutes before exercise. The bronchodilation begins few minutes after inhalation of short-acting β-agonists and lasts from 4 to 8 hours.
Long-lasting β-agonists are discouraged in treating acute exercise-induced asthma, because their chronic use might mask poorly controlled asthma.