"It’s about finding the rough edges around your comfort zone, smoothing them out, expanding and then finding the next edge.”

Most of us thrive when we’re nesting in our physical and mental comfort zones: a state of being where we feel safe and secure and have the general rhythm of our lives figured out. Anything that takes us out of this bubble becomes unsettling and uncomfortable, and we’re generally apprehensive about—or do our best to avoid—situations that force us to face the great unknown. But the danger of subscribing to this philosophy of self-preservation is complacency—of becoming content with easy living instead of challenging our limits and tapping our full potential.

Pushing ourselves past our established habits can positively affect how we live our lives. One of the ways we can induce this effect is by engaging in endurance activities that thrust us far beyond our normal routines. These...