“Independent study that utilized DANA to evaluate the effects of metabolic suppression and sedation on cognition. Objectives: A decrease of carbon dioxide production by astronauts during spaceflight could significantly prolong the active life of CO2 scrubbers, which are used to remove excess carbon dioxide from the air in spacecraft to maintain a safe and healthy environment. Metabolic suppression decreases carbon dioxide production. Sedation and cold environments are required for metabolic suppression. This study was conducted to test a new oral formulation of dexmedetomidine (a sympatholytic anesthesia) as a potential sedative to induce metabolic suppression and reduce CO2 production during spaceflight. Methods: 6 subjects (4 males; average age of 30 years old) participated in this crossover trial where they were exposed to a cold environment and a thermal neutral environment and sedated with dexmedetomidine for 3 hours in each condition. The subjects completed a DANA test battery prior to and immediately after exposure to each environmental condition. Subjects also completed the same DANA text battery every 30 minutes during the 150-minute recovery time following each environmental condition exposure. Results: There was a significant difference in performance on DANA between baseline and start of recovery, regardless of thermal exposure. However, the cold condition resulted in performance decrements for a longer interval. These results suggest that after metabolic suppression, a period of cognitive recovery may be required before completing mission critical tasks.”