Should I keep the Air Separator running during the training session?

Yes, this answer is the same for LiveO2, LiveO2 AC and the ExtremeO2 sys­tems. Mainly the air sep­a­ra­tor is left on to pro­vide make up vol­ume for the LiveO2 sys­tem. For the ExtremeO2 sys­tem the Air sep­a­ra­tor also cre­ates the oxy­gen deplet­ed air so it is required to be ON dur­ing use. Leaving the sep­a­ra­tor on just pri­or to use and dur­ing use also assures that the oxy­gen rich air con­cen­tra­tion in the reser­voir is also main­tained. The inter­nal mem­brane is designed to be slight­ly per­me­able and some mix­ing with air occurs. When the sep­a­ra­tor is not run­ning the vol­ume will drop and if left long enough the reser­voir will slow­ly deflate on its own.