A method according to an embodiments includes administering at least two Cyclic Variations in Altitude Condition (CVAC) sessions to a mammal disposed in a pressure vessel unit. The at least two CVAC sessions each have a duration of at least twenty minutes. The at least two CVAC sessions each include a start point of ambient pressure at a delivery site, an end point of ambient pressure at the delivery site, and a plurality of atmospheric pressure targets executed between the start point and the end point. The administering is configured to treat at least one of loss of sensation and chronic pain.