 The prevalence of exercise-induced bronchoconstriction EIB has been reported to be around 70 to 75 among patients with clinically established asthma. Airway cooling and drying are thought to cause the release of inflammatory mediators, such as histamine and leukotrienes, which then mediate clinical EIB symptoms. Pretreatment with a variety of medications will ameliorate EIB. Albuterol has been found to be more effective in minimizing EIB than theophylline, ipratropiom, cromoglycate, etc. Tested using a treadmill exercise challenge, the newer formulations of albuterol MDI with HFA as propellant have been demonstrated to be as effective as those with CFC as propellant in protecting asthma patients from EIB in children and adults. 