Folks expecting a simple lifestyle tweak be warned, the original training is by Wim Hof and in addition to the (fairly intense) breathing exercises involves lying in snow for 30min and hiking a snowy mountain, both partially naked.

While participants replaced the cold exposure element with a cold shower after they went home from the training, the techniques still took 2-3 hours per day. Also on the day of the data collection, they performed the techniques right before being exposed to E coli, so they had "advance warning" as it were.

Still very cool to see the immune system changes observed, since that's rare, but definitely requires a commitment to produce it in its current format.