[Exercise-induced asthma and placebos].

The effectiveness of a placebo in 15 patients with exercise-induced asthma (E.I.A., decrease of FEV1 by more than 10% after a standard run uphill on a treadmill) has been measured. 7 patients repeated the test without placebo protection, to separate the psychological effect of placebo from the emotional influences of the unusual environment of a technically highly developed hospital and adaptation to test procedures. On selection day FEV1 in % of preexercise value 10 min after exercise was 68.2 +/- 7.9% and on control day 67.1 +/- 9.5% (no statistical difference). The second stage comprised 14 patients who took the placebo or Cromolyn (Lomudal) before exercise; on selection day FEV1 in % of preexercise value 10 min after exercise was 70.1 +/- 4.8%; on placebo day it was 76.0 +/- 3.4% and on Cromolyn day 90.7 +/- 3.3%. There was statistically significant (p less than 0.025) protection by placebo. However, the protective effect of Cromolyn was much better than that of placebo (p less than 0.005). Placebo has a significantly greater protective effectiveness in E.I.A. than expected, and one much greater than previously suggested in preexisting asthma. As environmental influences were ruled out, the only explanation for the high degree of protection by placebo is the patients' trust in the placebo.