Last week, I took off on another training hike in preparation for the 29029 Everesting challenge, now coming up in less than a month. Our group, which included my colleague Emily Shane and two others, selected an 18-mile trail, which we covered in about 8.5 hours. This was a big step toward our Everesting experience, where we’ll hike more than 30 miles over 36 hours.

About 7 hours into this strenuous hike, our legs were tired, some of our crew had run out of water, and we couldn’t wait to just stop. We’d hit the point when doubt starts to creep in. Our small crew started talking about what motivated us to sign up for this type of challenge. Each of us shared details of our personal stories, what drives us and what we hope to gain from this experience.

I quickly noticed a trend in our conversation. Collectively, we recognized the life lessons we all learn when we aim to accomplish an outsized challenge. We also spoke about the personal influences in each of our lives: great mentors, coaches, friends – and the mantras we pick up along the way from these people.

As we were hiking a 20-40% incline on mile 14, our small group started voicing these positive mantras out loud in a round-robin type of fashion to keep the energy up and positivity flowing.

If it doesn’t challenge you, it doesn’t change you.

Growth and comfort do not coexist.

The hard is what makes it great.

I didn’t come this far to only come this far.

No matter what, remember tomorrow.

We are here to empty the tank. Leave it all on the mountain.

A few years ago, during training for a half-marathon, I kept getting stuck at mile 8. I started studying mindset coaching with retired Navy SEAL Chadd Wright, now an elite ultra-endurance athlete. One of his recommended tactics is a practice called thankful miles. At each mile, you say out loud something you’re grateful for. “We aren’t going to be negative,” Chadd says, “We aren’t going to give our pain a voice. There is power in what we articulate out loud.”

I am not good enough.

I don’t have enough experience.

I don’t have what it takes.

These are dangerous lines to feed our minds.

These important lessons have profoundly impacted my life, and it’s simple. This week, I’m paying attention to what I say out loud. The power in what we say defines how we see ourselves and what we can accomplish.