E-sports — which is to say, competitive, professional online video gaming — have exploded in popularity in recent years.

In fact, experts have predicted that e-sports viewership is likely to surpass that of traditional sports leagues, including the NBA and MLB, by 2020. Indeed, esports revenue is likely to climb to more than $900 million this year as television channels like ESPN continue to incorporate e-sports into their daily lineups, and streaming services like Amazon's Twitch become more mainstream.

In a world where competitive video games have the potential to be as lucrative an industry as professional sports, the title "pro gamer" has evolved massively since the '90s, where a relatively small group of die-hard gamers played in relatively unnoticed tournaments for community notoriety and occasional prize money.

In the modern world of e-sports, pro gamers are salaried employees with medical benefits and 401-ks, and who have personal nutritionists and fitness trainers. They are celebrities and role models for the fans who purchase jerseys and other merchandise in their honor. They also happen to play the same video game for 8 to 10 hours a day.

Business Insider got to interview professional gamers who play in the Overwatch League, competing at the highest levels of Blizzard's acclaimed and best-selling competitive first-person shooter "Overwatch."

We got an inside look at the ups and downs of their everyday lives and, the journeys that they've taken to get to the highest level for their game of choice.