Acute exercise-induced irisin release in healthy adults: Associations with training status and exercise mode.

There is a growing interest in exploring irisin response to acute exercise; however, the associations of acute exercise-induced irisin release with training status and exercise mode are not fully understood. This study was primarily designed to evaluate these associations. Sixteen healthy adults (8 trained versus 8 untrained) underwent a bout of cycling at 80% of maximal oxygen uptake (VO2max ) for 50 min, with blood drawn pre-, 10-, and 180-min post-exercise. Another 17 healthy adults performed 2 bouts of graded exercise (cycling and running) until exhaustion on separate days using a randomized cross-over design, with blood taken pre-, 0-, 10-, and 60-min post-exercise. Circulating irisin, creatine kinase (CK), aspartate aminotransferase (AST), and myoglobin (Mb) were measured, and their respective areas under the curves (AUCs) were calculated. Irisin increased 10-min after 50 min of cycling at 80% of VO2max , while its changes from baseline to post-exercise and the amount of exercise-induced irisin release (presented as AUC) were comparable between trained and untrained adults (all P > .05). Irisin remained elevated 10-min post-exhausting running but decreased towards baseline 10-min post-exhausting cycling. Exhausting running induced an increase in irisin release for the whole course of exercise and recovery periods, but cycling did not. Acute exercise-induced irisin changes seemed not related to changes of CK, aspartate AST, and Mb in general. In conclusion, acute exercise-induced irisin release is not associated with training status but might be affected by training mode. Future studies are required to investigate which exercise mode might be most efficient in altering irisin.