Exercise-induced bronchoconstriction
（重定向自Exercise induced asthma）
![This forest plot shows the effect of vitamin C (0.5 to 2 g/day) on post-exercise decline in FEV1 in three randomized placebo-controlled cross-over trials with asthmatic participants. Constructed from data in Fig. 4 of Hemilä (2013): http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3686214. The three horizontal lines indicate the three studies, and the diamond shape at the bottom indicates the pooled effect of vitamin C: decrease in the post-exercise decline in FEV1 by 48% (95%CI: 33 to 64%).](/Images/godic/202501/12/Vitamin_C_and_exercise-induced_bronchoconstriction.svg2431.png")
Exercise-induced asthma, or E.I.A., occurs when the airways narrow as a result of exercise. The preferred term for this condition is exercise-induced bronchoconstriction (EIB); exercise does not cause asthma, but is frequently an asthma trigger.