This is the FASTEST and most EFFECTIVE breathing relaxation technique I have ever found. 5 stars plus plus!! I believe that it is important to have a LONG exhale of 6 to 10 seconds, maybe thru pursed lips to really slow the heart rate. This increased thoracic pressure above the diaphragm works by slowing the refilling of the heart. Unless you hyperventilate by breathing faster than 6 breaths per minute, and become lightheaded, I see no harm in doing a longer PS session of a few minutes or a couple of dozen breaths. That is, titrate the duration to how distressed you feel in the moment. Add in a COOL WATER routine to hands, face and back of the neck, and with the PS technique you can be chilled out in under a minute. For safety sake, take away any pressing mental challenges for the next hour. Be kind to yourself!