Obstructive sleep apnea (OSA) is a chronic disorder caused by intermittent obstruction of the upper airways during sleep. Neurocognitive deficits in this population have previously been associated with altered brain metabolism. In fact, a recent pilot study suggests that global cerebral metabolic rate of oxygen (CMRO2) may be a potential marker of oxygen metabolic dysfunction in this population. Here, we present preliminary results from an ongoing study designed to quantify CMRO2 in subjects with OSA and matched controls. Initial results suggest that apneics have overall lower baseline CMRO2 and increased response to volitional apnea, a paradigm to mimic spontaneous apneas.