The beneficial effects of 15 units of high-intensity circuit training in women is modified by age, baseline insulin resistance and physical capacity

Aim: To investigate the effect of a single and 15 units of high-intensity circuit training (HICT) programme on glucose metabolism, myokines' response and selected genes' expression in women. Methods: Thirty-three, non-active women (mean age: 38 +/- 12) were split into a HICT (n = 20) or a control group (CON, n = 13). The training protocol included three circuits of nine exercises with own body weight as a workload performed 3 times a week for five weeks. The CON group performed HICT twice. Blood samples were taken before, 1 h and 24 h after the first and last unit to determine IGF-1, myostatin, irisin, decorin, HSP27, interleukin15 concentrations using the ELISA immunoenzymatic method. To evaluate HSPB1, TNF-alpha and DCN mRNA, real-time PCR was used. Pre- and post-intervention, the oral glucose test and body composition assessment were completed. Results: The following parameters tended to decrease after the 5-week HICT program: insulin and HOMA-IR Training diminished insulin/IGF-1 ratio (51% CI: -63% to -34%) and induced the drop of myostatin concentration but significantly only among middle-aged women and at baseline insulin resistance. Conclusion: Obtained data revealed that HICT improved an insulin sensitivity and diminished myostatin concentration among older, insulin-resistant women with lower baseline physical capacity. (C) 2019 Elsevier B.V. All rights reserved.