The research builds on previous studies suggesting that caffeine may be associated with decreased asthma symptoms. In the current study, researchers studied 10 asthmatic patients. Sixty minutes before exercising on a treadmill, participants were given doses of caffeine of 3, 6, or 9 mg/kg of body weight, or Placebo for the control group. The study was what is known as a double−blind, "double−dummy" paradigm (this last term simply implies that all participants eventually received all doses and the placebo at different points in the experiment). Researchers tested pulmonary function 15 minutes before, and 1, 5, 10, 15, and 30 minutes after the exercise challenge.
[T]aking 9 mg/kg of caffeine ... was just found to be just as effective at reducing EIA symptoms as using an albuterol inhaler.