Yet unpublished data (CMO 2014-1374) showed the effects of these two breathing techniques in the absence of cold exposure (or meditation) on plasma adrenaline levels. The investigators found these to be strongly correlated with the anti-inflammatory effects previously found. Both breathing techniques resulted in comparable increases in plasma adrenaline levels. Furthermore, adrenaline levels in subjects trained by Hof were comparable to those that were trained by an independent trainer previously not familiar with the intervention developed by Hof. Finally, adrenaline levels in subjects trained for 4 days were similar to those who were trained for only 2 hours.