Acute and Chronic Effects of High-Intensity Interval Training (HIIT) on Postexercise Intramuscular Lipid Metabolism in Rats

Abstract

Recovery from exercise refers to the period between the end of a bout of exercise and the subsequent return to a resting or recovered state. It is a dynamic period in which many physiological changes occur. A large amount of research has evaluated the effect of training on intramuscular lipid metabolism. However, data are limited regarding intramuscular lipid metabolism during the recovery period. In this study, lipid metabolism-related proteins were examined after a single bout of exercise in a time-dependent way to explore the mechanism of how exercise induces intramuscular lipid metabolism adaptation. Firstly, all rats in the exercise group underwent a five-week training protocol (HIIT, five times/week), and then performed a more intense HIIT session after 72 h of the last-time five-week training. After that, rats were sampled in a time-dependent way, including 0 h, 6 h, 12 h, 24 h, 48 h, 72 h, and 96 h following the acute training session. Our results discovered that five weeks of HIIT increased the content of intramuscular triglyceride (IMTG) and enhanced the lipolytic and lipogenesis-related proteins in skeletal muscle. Furthermore, IMTG content decreased immediately post HIIT and gradually increased to baseline levels 48 h postexercise, continuing to over-recover up to 96 h postexercise. Following acute exercise, lipolytic-related proteins showed an initial increase (6-12 h) before decreasing during recovery. Conversely, lipogenesis-related proteins decreased following exercise (6-12 h), then increased in the recovery period. Based on the changes, we speculate that skeletal muscle is predominated by lipid oxidative at the first 12 h postexercise. After this period, lipid synthesis-related proteins increased, which may be the result of body recovery. Together, these results may provide insight into how the lipid metabolism-related signaling changes after chronic and acute HIIT and how protein levels lipid metabolism correlates to IMTG recovery.

The role of GPR81–cAMP–PKA pathway in endurance training-induced intramuscular triglyceride accumulation and mitochondrial content changes in rats

“…High-intensity interval training (HIIT) can result in metabolic adaptations of skeletal muscle, which include IMTG accumulation and mitochondrial content increase. Data collected in our lab have validated this point: Chen and Zhou et al found that a 5-week HIIT regimen increased the content of IMTG [ 4 , 5 ]. Our published results also suggest that a 6-week HIIT program can induce IMTG accumulation and elevate the amount of mitochondria in skeletal muscle [ 34 ].…”

“…The study discovered that the cAMP–PKA pathway regulated the inhibition of lipolysis, leading to lactate-induced accumulation of IMTG. Lactate injection might also increase mitochondria content, while the contributions of the cAMP–PKA pathway might be limited [ 4 , 5 ].…”

Exercise-induced BDNF promotes PPARδ-dependent reprogramming of lipid metabolism in skeletal muscle during exercise recovery

“…2D), further confirming their fatigue-prone phenotype. To further support the importance of BDNF in muscle recovery after exercise, mice were subjected to two consecutive exhaustive tests with a 6-hour recovery in between, which is sufficient to replenish the IMTG in normal mice ( 36 ). Although Fl/Fl mice displayed no reduction in running endurance after the first test, the running capability of MBKO mice was significantly reduced in the second test (Fig.…”

“…Because PPARδ activity is also essential to maintaining FA uptake ( 52 ), it seems logical to hypothesize that PPARδ plays a role in post-exercise IMTG recovery. Intramyocellular FAs have been suggested to induce Ppard expression, but this hypothesis is contradicted by FA incubation failing to alter Ppard expression in cultured myotubes ( 12 , 36 ). Hence, the upstream factor that promotes Ppard expression after exercise remains unknown ( 12 , 53 ).…”

The Effect of Interval Training on the Displacement Speed of Male Good Boxers

“…Test item selection. different distances, which require the athletes to complete the training at the fastest possible speed, and the content of the movements developed in the training should be similar to the structure of the boxing game[7][8][9].…”