As a dedicated morning or pre-cold-exposure practice when you have a few quiet, seated minutes. Not as a quick calming tool, and never on the go.
The rounds of deep over-breathing temporarily lower CO2 and shift blood pH, which is what produces the tingling and lightheadedness; the retention that follows drives oxygen saturation down and adrenaline up. In trained practitioners this appears to grant an unusual degree of voluntary influence over the sympathetic nervous system and the body's inflammatory response.
A landmark 2014 study found trained Wim Hof practitioners could blunt their immune response to an injected endotoxin, and small studies report effects on mood and inflammation markers. The research is early, mostly small, and often industry-adjacent, so treat the method as a potent but experimental practice, the physiological stress is real, which is exactly why the safety rules below are non-negotiable.
Developed by Dutch athlete Wim Hof ('The Iceman'), who set multiple cold-exposure records and built a method combining cyclic over-breathing, breath retention, and cold training. It draws conceptually on Tibetan Tummo ('inner fire') breathing but is a distinct modern protocol.
Master the breathing on its own for a couple of weeks before ever combining it with cold. Extend retention time gradually and only while it stays comfortable, chasing a longer hold than last time is how people push past their limits.
Why do I get tingling and lightheaded?
That's the expected effect of temporarily lowered CO2 from the deep breathing. It passes quickly once you return to normal breathing.
Can I do this before a cold shower?
Do the breathing seated and fully finished FIRST, then get into the cold. Never do the breathing while in the water.
Safety
Breathwork is a complement to (not a replacement for) professional medical care. If you have a heart, respiratory, or blood-pressure condition, are pregnant, or feel unwell, check with a clinician before practising breath-hold techniques.