Figure 1. Physiological adaptations to HIIT.
(A) Experimental overview. (B). Subject characteristics. (C). Five weeks of HIIT increased maximal oxygen uptake (V̇O2max) and incremental peak power output (iPPO). (D) HIIT increased whole-body fat oxidation during submaximal exercise (50–150 W) without altering (E). carbohydrate oxidation. (F). HIIT increased mitochondrial respiration in skeletal muscle (LN: leak respiration, FAO: fatty acid oxidation, CID: submaximal CI respiration, PD: submaximal CI +II respiration, P: oxidative phosphorylation capacity, E: electron transport system capacity, ECII: succinate-supported electron transport system capacity). (G). HIIT increased skeletal muscle citrate synthase (CS) activity. (H). Analytical workflow. Summary statistics are mean ± SEM (n=8). * p<0.05, ** p<0.01, *** p<0.001.