Fig. 6
Oxygen consumption during stages of sleep and calculated metabolic water production and secretion. Rates of whole-brain oxygen consumption (CMRO2) in human subjects [144, 145] demonstrated no change during rapid-eye-movement (REM) sleep compared with resting, awake, non-stimulated subjects (NS, not statistically significant). However, CMRO2 fell significantly, by 5% and 25% during light and deep sleep, respectively, and calculated production of total water and secreted water from oxidation of glucose decreased proportionately during these sleep stages