Andrei Arlovski understands if you wonder why he’s still hanging around.

The former UFC heavyweight champion just celebrated his 40th birthday in February and is in the midst of a three-fight slump, yet 2018 tied his own personal record for the most active campaign of his entire mixed martial arts career. Not since 2000, the year of his first professional win, did Arlovski compete as many times as he did last year. Two decades into a likely Hall of Fame career, and yet “The Pitbull” is still at it, cranking out four-fight calendar runs with the gusto of a man half his age. Win or lose, that old fanged mouthpiece still means something every few months, and that alone is impressive enough.

And so the former heavyweight king is set to make another nostalgic go around the old stomping grounds, his first of 2019, this time against power-punching prospect Augusto Sakai on April 27 at UFC Sunrise. In terms of fight lives, Arlovski has lived plenty. He is a breathing reminder of a bygone golden age, but even as he creeps upward in age, the man who captured his UFC strap back in 2005 wouldn’t have it any other way.

“My first jiu-jitsu coach, Dino Costeas, told me discipline is remembering what you want,” Arlovski says ahead of UFC Sunrise. “F*ck, every day when I wake up, I remember what I want, why I am doing this f*cking over and over at age 40 and one of the oldest guys in the UFC still in this, still going. … It’s just a number. You can feel like that [if you want to], but I’m pretty much one of the first guys who comes and pretty much one of the last ones who leave the gym, I have at least two or three workouts a day. So I’m good, I feel good.

“I have a good example. In boxing, George Foreman became champion at age 46, of course, and Randy Couture, it didn’t matter that he was fighting at 40 years old. Dan Henderson. There’s a lot of guys, so it doesn’t matter. It’s just a number. Age is f*cking just a number. It depends how you feel inside, and I’m a happy guy. I love this. I’m doing what I love to do and my wife lets me do what I love to do. She supports me all the time, she’s an [incredible] lady, so I’m a happy person, fighter, and father.”

Arlovski’s road has had its ups and downs. That, he doesn’t shy away from. Back in 2011, with the glory of his Octagon days behind him, Arlovski lost four consecutive fights — three of them via brutal first-round knockouts — and appeared to be at the end of the line. Check the wayback machine and you’d find an internet overflowing with eulogies for “The Pitbull,” wistful lamentations for a storied career that had reached its dead end.

But then, seemingly out of nowhere, emerged the run that redefined Arlovski’s career for a brand new generation: A 10-1 stretch that led the former champion to the precipice of the UFC’s unlikeliest title shot. Overnight, the old guard rode once more.

Of course, things slowed down after that. Arlovski has only had his hands raised in two of his 10 fights since, but the mere fact that he is still around and winning competitive fights as recently as last year is still remarkable in and of itself. He has effectively survived and thrived through four different eras of the sport, from the dark ages to Spike TV to FOX to ESPN. And to hear him tell it, the key to his improbable longevity is a simple one.

“Listen, my wife takes care of my face, like expensive [products] on my face every night,” Arlovski says with a laugh. “No, it’s one step after another. Just trying to, with age, you have to decide what’s more important for you, choose what’s more important for you as a person, father, husband. So I just listen. Fifteen years ago it was like party time all the time. Now I just understand that I have a short window of a few more years, and it’s very nice of the UFC and actually Dana White to give me all this time in the UFC to do [what I love].

“I’m happy that I’m still [here] and still alive. I was a pioneer, and I say this pretty much all the time, but it was good time to be with the UFC. It made me who I am. … I remember when this started. I didn’t start right at the beginning — it was like 1994, I started [a few years later] — but now it’s like, the sport is growing with mainstream sports and the world is [paying attention], and now we’re on ESPN. It’s crazy. It’s f*cking fantastic.”

The love of the game is everything now to Arlovski, especially at this point in his run, when he can feel the end bearing down at every turn. It’s why he was so startled when the UFC’s drug-testing czar, Jeff Novitzky, phoned him earlier this year with news about his December fight against Walt Harris at UFC 232. Arlovski lost to Harris via narrow split decision, and he’s been around the sport long enough to know that a call from Novitzky is rarely good news.

Everything ended up working out okay. Harris, it turned out, had tested positive for a banned substance and the result of the fight was overturned into a no contest. But for a split second, Arlovski was terrified that some wayward substance had crept into his own system through nefarious means, which would mean a long suspension — and, at his age, an unceremonious end to his final UFC run — was upon him.

“I got the call from Jeff Novitzky and I f*cking started swearing, I said maybe something’s wrong with me,” Arlovski remembers, laughing again. “It was just like, ‘What the fuck, man? You’ve got a call from Jeff.’ First of all, right away, you have to be ready for any f*cking news, good or bad. And when he told me, it was like, oh f*ck, it was a relief. I said, okay.

“It was good for me because the fight was a no contest. Instead of another loss to him, just a no contest. Now I have another young stud and I just have to make some decisions about what went wrong in my fight against Walt and just do my homework and move forward.”

Once his tainted supplement worries were behind him, Arlovski turned his attention to Sakai. The Bellator veteran was an unknown to “The Pitbull” before UFC matchmakers floated out his name, but Arlovski has since come to respect his young adversary. Ten of Sakai’s 12 wins have ended in knockouts, and Arlovski is eager for the challenge.

“He’s young, aggressive, still 27, like you mentioned, so I think it’s pretty much my chance to fight someone older than me in the UFC,” Arlovski jokes. “He’s a good striker, very powerful. It’s good. He’s a young stud, [he’ll] push me.”

Arlovski knows another loss at UFC Sunrise could signal the end of his time in the promotion. Even with his name recognition, his recent résumé needs some green to accompany the red for UFC officials to justify keeping Arlovski around.

But the 20-year veteran has been here before.

Twice in his career, he suffered four-fight slumps that prompted onlookers to call for his retirement, and both times he bounced back with improbable win streaks. So this is nothing new, and Arlovski remembers well the lessons he learned from those past tribulations. After all, he always has fought his best with his back pressed firmly against the wall.

“One hundred percent, it helps me because [I know how to focus on] my reasons [why I’m doing this],” Arlovski says. “One of them is six-and-a-half years old and the other is nine months. So f*ck yeah, this is my motivation and I always know that, no matter what, I’m doing it for them. That’s it, it’s simple.”