Avoid comfort, challenge yourself and stay disciplined.

The people of Sparta, the ancient Greek city-state, defended their homeland through intense physical and mental preparation. It might be thousands of years later, but you can still learn from their legendary abilities and become a Spartan yourself.

Life’s comforts make our existence predictable and boring. They disconnect us from our true passions and goals, but you can overcome that lethargy by taking a real jump into life.

That jump could be extreme sports, for instance. Joe de Sena, the author, organizes various extreme sports events, such as the Death Race. Death Race isn’t just an over-the-top name – participants actually sign a waiver certifying that they know they could die during the challenge.

The Death Race contains several events, such as diving for pennies in cold water, walking 50 kilometers and lifting rocks for hours. Afterwards, de Sena often gets grateful messages from participants who say it changed their lives for the better.

However, you’ll only be able to handle physical challenges like this if you have strong endurance skills. So build your endurance through self-discipline and by delaying your own gratification.

It’s easy to get quick satisfaction in the modern world, but resisting instant gratification is an important part of personal development; Walter Mischel’s famous marshmallow experiment does a good job of illustrating this.  

In the experiment, Mischel presented children with a marshmallow. The children were told that if they waited to eat it, they’d get another. Mischel then left the room to see what the children would do when left alone with the treat. Years later, Mischel follows up on the lives of these children.

The study showed that the children who had the self-discipline to resist the marshmallow grew up to be wealthier and healthier than those who didn’t. Challenges in adulthood are similar: you have to resist immediate gratification and hold out for something better.

At any given time, life can be easy or challenging – but it’s up to you to make life fulfilling. You never know when hard times will hit, so keep building your endurance skills. You’ll be more prepared for challenges and more adventurous, too.