This past year, I've read some phenomenal articles on mental strength. And after reading Jeff Haden's tips for becoming mentally tougher, I began thinking through more ways to hone this vital leadership skill.

To me, mental strength means persevering through challenging situations while keeping your confidence intact. Although you might feel as though writing makes you vulnerable to judgment, regularly exposing yourself to the harsh critics who'll challenge you is the best way to build an unshakable foundation of mental strength and become a more influential business leader in the process.

Writing exercises your brain

Staying physically tough requires preparation, discipline, and consistency. I remember training for sports when I was younger. The only way I could improve was by working out and training a few times a week. If I got lazy, it showed on the field.

Your brain is a muscle. Becoming mentally tougher works just like gaining physical strength; you have to exercise it to get stronger. But that doesn't mean clocking in an annual visit to the gym or doing a sudoku puzzle every once in a while.

You have to consistently work out your brain to strengthen it. For me, writing out my ideas helps me retain information, and it's one of the best mental workouts to stimulate the mind.

Many successful business leaders are also devoted writers

Fortunately, I'm always surrounded by highly intelligent people. One key characteristic they all seem to share is that they write out their thoughts on a regular basis. For example, our initial investor, Brent Beshore, always wrote notes before and during our meetings, and he continues to write every chance he gets.

Other impressive industry leaders such as Shane Snow or Dharmesh Shah are also avid writers. You've also probably read articles from Brad Feld, Peter Thiel, Tony Hsieh, and others--the list of thought leaders goes on and on. It makes sense that intelligent people have insights to share, but putting them on paper is the best outlet for organizing, understanding, and articulating them effectively. Making a commitment to provide value to readers also challenges these thought leaders to stay sharp, question the status quo, and become all-around smarter leaders.

Spelling out your ideas paints a more complete picture

If you keep your ideas to yourself, you have no one to point out the flaws or holes in your logic. And that can lead to an ugly cycle of ignorance and inflated confidence. When you're writing, you can dispel your ideas and take a more critical eye to them. And if they're published, readers can also offer feedback.

Take a look at my LinkedIn article, for example. You'll see that many of the commenters question my title choice and impose strong opinions on my decision to single out leaders. People will always challenge certain stances I take, and it's one of the best ways to stay sharp. You learn how to approach your ideas from new perspectives, defend your thoughts, and fuel educational conversations. It's not a battle of who can yell the loudest; it's a way to gather diverse opinions and sift out the jewels. After a few beat-ins, you learn to take the punches and recover to be mentally stronger than before.

I'm no psychologist, but I do interact with more experts than anyone I know. And the common denominator among these intellectually curious people is their mental toughness and commitment to writing. Investing time in your mental acuity and strength through writing shouldn't be buried deep in your wish list; it should be a daily priority. And who knows--you might even earn the reputation as a trusted thought leader and reap the benefits that extend beyond your professional development.