A system for cooling the brain of a human subject, the system comprising: a cooling subsystem configured to input a flow of air or breathable gas, cool the air or breathable gas, and output a flow of cooled air or breathable gas to a line coupled to a device adapted to deliver the flow of cooled air or breathable gas to a human subject, the cooling subsystem including a flat gas block comprised of a thermally conductive material and a flat thermoelectric cooler coupled to the flat gas block, the flat gas block including an inlet configured to input the flow of air or breathable gas and an outlet configured to output the flow of cooled air or breathable gas; a flow control device coupled to the cooling subsystem configured to control a flow rate of the flow of the air or breathable gas input to the cooling subsystem and a flow rate of the flow of cooled air or breathable gas output to the line; one or more flow rate sensors coupled to the cooling subsystem configured to measure at least a flow rate of flow of cooled air or breathable gas; one or more temperature sensors configured to measure at least a temperature of a brain or a brain correlative site of the human subject and the temperature of the flow of cooled air or breathable gas; and a controller coupled to the cooling subsystem, the flow control device, the one or more flow rate sensors, and the one or more temperature sensors, the controller configured to adjust a cooling rate, the temperature, and the flow rate of flow of cooled air or breathable gas delivered to the human subject based on at least the measured temperature of the brain or the brain correlative site and the measured flow rate of the flow of cooled air or breathable gas to cool the brain of the human subject. a cooling subsystem configured to input a flow of air or breathable gas, cool the air or breathable gas, and output a flow of cooled air or breathable gas to a line coupled to a device adapted to deliver the flow of cooled air or breathable gas to a human subject, the cooling subsystem including a flat gas block comprised of a thermally conductive material and a flat thermoelectric cooler coupled to the flat gas block, the flat gas block including an inlet configured to input the flow of air or breathable gas and an outlet configured to output the flow of cooled air or breathable gas; a flow control device coupled to the cooling subsystem configured to control a flow rate of the flow of the air or breathable gas input to the cooling subsystem and a flow rate of the flow of cooled air or breathable gas output to the line; one or more flow rate sensors coupled to the cooling subsystem configured to measure at least a flow rate of flow of cooled air or breathable gas; one or more temperature sensors configured to measure at least a temperature of a brain or a brain correlative site of the human subject and the temperature of the flow of cooled air or breathable gas; and a controller coupled to the cooling subsystem, the flow control device, the one or more flow rate sensors, and the one or more temperature sensors, the controller configured to adjust a cooling rate, the temperature, and the flow rate of flow of cooled air or breathable gas delivered to the human subject based on at least the measured temperature of the brain or the brain correlative site and the measured flow rate of the flow of cooled air or breathable gas to cool the brain of the human subject.