This is a guest post from Jason Duff, founder and CEO of COMSTOR Outdoor.

I felt the worst at the exact moment I was being recognized the most.

On the outside, I was celebrated as a successful entrepreneur. I had built several multimillion dollar businesses that employed hundreds of people in my local community.

On the inside, everything was falling apart. Under extreme stress, I was sleeping four hours per night and neglecting my most important relationships. As a result, I developed debilitating acid reflux. Not only did I have surgery and go on daily medication, it was so painful to speak that I could only whisper.

I was 25.

I turn 35 in August, and that's made me reflect on my journey. I often ask myself, "In the last 10 years, what have I learned about living a good life?"

Over and over, my mind has kept coming back to one lesson I've learned...

The Dark Side Of Ambition

As a society, we celebrate ambition without really questioning its costs.

In my 20s, my identity was so intimately tied to my businesses that I was always preoccupied with work.

I looked forward to holidays like Thanksgiving: not for spending time with friends and family, but for catching up on work and creating to-do lists. I lost a number of friendships, and my family relationships deteriorated.

I also wasn't there for myself. For four years straight, I didn't go out on a single date despite feeling lonely. I worked 15-hour days for 7 days a week. On many days, I would drink a six pack of soda just to stay energized. As my fatigue got worse, my headaches turned into migraines.

When one of my close mentors passed away, I finally realized that work is not everything.

When I took a step back, I realized that all of my physical problems were a result of my psychology. Even when my businesses were successful and growing, I always felt behind. Underneath my ambition was the fear of missing out, the fear of not being successful enough in the public eye.

Over time, I've freed up my calendar for opportunities to reset and rejuvenate. Now, every evening, I cook a meal with my partner. On weekends, I spend time with friends and family and take lots of naps. Recently, I spent a day just watching my nephew, rather than catching up on the hundreds of emails in my inbox.

The Ambition Dilemma

Ambitious, driven people have the exact opposite problem that most people have. Their main risk isn't coasting along or underworking. Their main risk is overworking. That's what happened to me.

When you overwork yourself hard and long, you first destroy your body and relationships. Then, after burnout, you destroy your professional life.

In order to reach our full potential in life, we must learn how to ride the wave between underwork and overwork. That means mastering the ambition sweet spot.

Staying in the ambition sweet spot isn't a challenge that we figure out once and never have to worry about again. It's a part of ourselves that always needs to be managed. Malcolm Gladwell brilliantly captured this dilemma in a recent interview when he spoke about the world of elite runners:

"You're walking a fine line between adequately preparing for races and overtraining, which leads to injury [and] burnout... Running is all about not getting injured. So you have to rein in all these tendencies -- your obsessiveness.

"You want to do that 10th repetition, but you know logically after the 9th that's enough. You pushed the body as far as it can go... You can't do 10! You have to be tough enough to say, 'No, no, no I have got enough for the day,' and walk away."

More and more top leaders are looking at ambition differently and talking about it publicly. Sheryl Sandberg leaves work at 5:30 pm to be home with her kids. Facebook co-founder Dustin Moskovitz wrote a viral article on how he regretted overworking in his 20s. Bill Gates does his own dishes every evening. Brian Scudamore has a 250 million dollar company, while he takes Fridays off and spends Mondays just thinking.

Let's celebrate these leaders, because they show that it is possible to have an impactful professional life as well as a personal one that is meaningful and fulfilling.

Redefining ambition at 35

While I'm still the same ambitious entrepreneur I was in my 20s, I'm no longer passionate about just being successful professionally. I'm also passionate about being a good friend, a good partner, and a good son. I'm passionate about being healthy, grateful, and energized.

Frankly speaking, I'm not quite in the ambition sweet spot yet. I still probably work more than I should, but I'm proud of the progress that I've made, and I look forward to the next ten years.