What Doesn't Kill Us: how freezing water, extreme altitude, and environmental conditioning will renew our lost evolutionary strengthWe like to sit in air conditioned comfort, yet each year millions of ordinary people train in CrossFit boxes, compete in Tough Mudders, and challenge themselves in Spartan races. They are connecting with their environment and, whether they realise it or not, unlocking their hidden evolutionary potential. No one exemplifies this better than Wim Hof, whose remarkable ability to control his body temperature in extreme cold has sparked a whirlwind of