Muscle glycogen metabolism is rapidly dysregulated in critical illness, which may have implications for muscle ATP resynthesis and ICU-acquired weakness.

The association of skeletal muscle metabolism with intensive care unit (ICU)-acquired weakness (ICUAW) is not clear. We report for the first time that reduced muscle ATP content by day 7 of ICU stay persisted after 6 mo and tended to be associated with ICUAW. Moreover, lower muscle glycogen and greater muscle lactate were observed earlier at day 1 compared with elective surgery patients. These changes reflected the expression of genes related to glycogen metabolism, which were predictive of mortality.