Exercise-induced bronchoconstriction (EIB) is a common occurrence in asthmatics, children and otherwise healthy athletes. Poor diagnostic accuracy of respiratory symptoms during exercise requires objective assessment of EIB. The standardised tests currently available for EIB diagnosis are based on the assumption that the provoking stimulus to EIB is dehydration of the airway surface fluid due to conditioning large volumes of inhaled air during exercise. 'Indirect' bronchial provocation tests that use stimuli to cause endogenous release of bronchoconstricting mediators from airway inflammatory cells include dry air hyperpnoea (e.g., exercise, eucapnic voluntary hyperpnoea) and osmotic aerosols (e.g., inhaled mannitol). The airway response to different indirect tests are generally similar in patients with asthma and healthy athletes with EIB. Further the airway sensitivity to these tests is modified by the same pharmacotherapy used to treat asthma. By contrast pharmacological agents, such as methacholine given by inhalation, act directly on smooth muscle to cause contraction. These 'direct' tests have been used traditionally to identify airway hyperresponsiveness in clinical asthma but are less useful to diagnose EIB. The mechanistic differences between 'indirect' and 'direct' tests have helped to elucidate the events leading to airway narrowing in asthmatics and elite athletes, while improving clinical utility of these tests to diagnose and manage EIB.