Metabolic changes explain how training mitigates the reduction in strength caused by sleep restriction.

Sleep is crucial for maintaining physiological and cognitive functions, including athletic performance; yet, nearly half of adults in Western countries experience sleep restriction. While human studies demonstrate that sleep restriction impairs strength and power performance, the underlying metabolic mechanisms remain poorly understood. This study aimed to characterize the impact of acute sleep restriction on strength performance and metabolic profiles in trained rats using untargeted metabolomics, a robust approach for identifying global biochemical changes. Twenty young adult Wistar rats were divided into two groups: Trained Control (TC) and Trained Sleep Restriction (TSR). All animals performed an initial Maximal Strength Test (MST) and were then trained for six weeks. On the day after the last training session, the animals were subjected to six hours of sleep restriction. At the end of the sleep restriction, the animals were subjected to the MST again and euthanized for blood collection and GC-MS metabolomics analysis. While both groups showed increased strength after training, the sleep-restricted group (TSR) exhibited reduced strength compared to controls (TC) by week 6 (p < 0.001), despite similar muscle glycogen levels. GC-MS Metabolomic Analysis revealed a pattern in the TSR group, characterized by lower concentrations of alanine, glutamine, serine, glycine, lysine, methionine, threonine, ornithine, tyrosine, norvaline, oleic acid, uric acid, and creatinine, as well as increased concentrations of phenylalanine and valine. In conclusion, acute sleep restriction reduced strength performance in trained rats by shifting metabolism away from efficient oxidative pathways, marked by decreased amino acid support for the Krebs cycle and neuromuscular homeostasis, rather than by changes in glycogen availability.