Joe Rogan couldn’t contain his emotions in a rare moment of vulnerability when thinking about his friends getting knocked out.Rogan, who hosts the most popular podcast worldwide and serves as a UFC commentator, is one of the most prominent figures in the MMA world.Rogan, left, is often partnered with his good friend and UFC legend Daniel Cormier in the commentary boothGettyHe is usually front and centre of the biggest UFC cards across the United States, with the best seats in the house to call the action from.Rogan has been involved with the UFC for almost 30 years now and has witnessed fighters from all different generations come and go, alongside all of the highs and lows of the sport.The 58-year-old has watched champions form and prospects crumble right in front of his eyes. One of the people with whom Rogan has built a special relationship over the years is former two-division UFC champion Daniel Cormier, who also now serves as a commentator in Dana White‘s promotion.Cormier is one of just four fighters to have held two UFC titles simultaneously, having claimed both the light heavyweight and heavyweight straps in 2018.He lost just three times in his 11-year, 26-fight career, but often it is the defeats that are remembered more fondly than the triumphs. Joe Rogan tears up at thought of Daniel Cormier being knocked out“It’s real hard when you watch your friends,” Rogan told comedian Ian Edwards on the latest episode of his podcast, explaining what it was like to call fights his friends are involved in.“It’s real hard when you watch your friends get beat up. It was real hard me watching Cormier when Jon Jones beat him up. That was hard.”‘DC’ shared one of the greatest rivalries in UFC history with Jones, losing to him at UFC 182, before being knocked out two years later in a fight later ruled a no-contest.After the Jones KO, Cormier bounced back with a stoppage victory over Volkan Oezdemir to assert his status as the UFC light heavyweight champion.Rogan has clearly been mentally impacted by watching some of his closest friends suffer brutal knockouts over the yearsPowerfulJRE - YouTubeCormier was stopped by Miocic in the pair’s rematch at UFC 241 before he retired following another loss to complete their trilogyUFCHe then knocked out Stipe Miocic in July 2018 to claim heavyweight gold, too, before defending the belt by submitting Derrick Lewis at UFC 230.Cormier then fought Miocic twice more to complete a trilogy, suffering back-to-back defeats in his final UFC fights, which led to his retirement.“The Stipe one was hard,” Rogan added, before pausing briefly to collect his thoughts.“Especially the one when Stipe KOed him against the cage. It’s just hard because you know them. You know them as human beings.”Rogan’s voice then became fully choked with emotion as he added, “You know what that’s going to do to them? It’s f***ing devastating. “It’s like you lost a family member or you lost a dog. It’s hard, man. I start crying.”Rogan had to interview a gutted Cormier straight after he was knocked out by Jones in the main event of UFC 214Getty Images - GettyRogan concluded by revealing how scared he was for former UFC heavyweight Brendan Schaub, who suffered several concussions towards the end of his career in MMA’s premier promotion.Rogan says the hardest watch was Brendan Schaub because he wouldn’t quit“The thing about Brendan that most people don’t know is how many concussions he took outside of the fights,” Rogan said.” So, you see the fights, but he used to spar with Shane Carwin. Shane Carwin was the interim heavyweight champion. “The biggest fists ever registered in the UFC. He had five XL fists. He’s so big. It was ridiculous. “He looked like Hulk from the Avengers. He doesn’t look like a real human, like all the other people were there, and then there’s Shane Carwin. He was a freak. “Brendan Schaub used to spar him all the time, and he would get knocked out all the time.“He would get concussions all the time. All the time. He got a concussion days before he fought Ben Rothwell. “He got a concussion days before he fought [Antonio Rodrigo] Nogueira. “So I knew about all that shit, I was seeing the effects, and I was like, ‘You got to get out. If you don’t get out now, there’s no happy ending.'”Rogan is set to make his return to the commentary booth for UFC 320 in Las Vegas on October 5.