while traditional intervention for an acute episode has been to have the patient breathe into a paper bag, causing rebreathing and restoration of co₂ levels, this is not advised. the same benefits can be obtained more safely from deliberately slowing down the breathing rate by counting or looking at the second hand on a watch. this is sometimes referred to as "7-11 breathing", because a gentle inhalation is stretched out to take 7 seconds (or counts), and the exhalation is slowed to take 11 seconds. this in-/exhalation ratio can be safely decreased to 4-12 or even 4-20 and more, as the o₂ content of the blood will easily sustain normal cell function for several minutes at rest when normal blood acidity has been restored.