Sterling: The sun beams down on a warm Dutch spring morning, and the Iceman’s students look wary as they watch him dump bag after bag of ice into the tub of water where they will soon be taking a dip.

The plan is to try to overcome the normal human reaction to immersion in freezing slush: gasping for air, shivering uncontrollably, and getting back out again as soon as possible.

Instead, under the direction of “Iceman” Wim Hof, the group of athletes is going to stay in the water for minutes practicing his meditation techniques, seeking possible performance or health benefits.

Hof, 52, earned his nickname from feats such as remaining in a tank of ice in Hong Kong for almost 2 hours; …