Chael Sonnen appears at the open workouts for Bellator 222...

Chael Sonnen appears at the open workouts for Bellator 222 on Wednesday, June 12, 2019. Credit: Newsday / Ryan Gerbosi

One day, you wake up, you’re 40 and suddenly it takes a little longer to roll out of bed, and the shower water needs to be a little warmer to help loosen up the muscles.

Not mentioned above: the ankle, knee, elbow, shoulder and back pain that showed up while you were sleeping.

Now add this to all of that: you’re a mixed martial arts fighter and you’ve been competing in what arguably is the most physically strenuous sport for your entire career.

“Yes, my body hurts all the time. It’s sore all the time. And particularly when you wake up,” said Chael Sonnen, a 42-year-old MMA fighter who will compete for the 48th time on Friday. “That’s a very real thing, but it’s not a new thing for me. I’ve been getting sore for 20 years.”

So what compels fortysomething-year-old fighters to continue to do this, to get up, go to their gym and twist and contort their bodies against the young’uns?

Athletes are not regular people. Sure, they may have some regular-people problems and activities, but they have non-regular occupations. They need their bodies to be in peak physical form to excel.

At some point, though, it takes a little more effort in your 40s to do the things you did at the same level you did them in your 30s. Or your 20s. And that’s if you even can reach those levels physically. Mentally, it may be harder to convince yourself to put your body through the grind of a training camp knowing how grueling and taxing it can be.

“We cannot compare ourselves with regular people,” Lyoto Machida, 41, said. “I am not a regular guy. Since when I was 4 years old, I’ve been this all those years. Once you do that, even if I get to 45, 50, if I still have the motivation to wake up, I can keep doing that. It depends on my mind.”

Sonnen will face Machida in a light heavyweight co-main event at Bellator 222 at Madison Square Garden. Combined age: 83. It is Machida’s 34th fight.

Machida and Sonnen are not alone in their desire and ability to put off retirement and compete in the full-body sport of MMA. Fellow Bellator fighters Fedor Emelianenko, Matt Mitrione, Roy Nelson and Cheick Kongo all continue to fight into their 40s. They’re all heavyweights.

Anderson Silva, the UFC middleweight legend, is 44 and fought for the 45th time last month. He is 1-4 since turning 40. He also was suspended for a year for an anti-doping violation, which USADA ruled as coming from a contaminated supplement. Daniel Cormier turned 40 in March and is set to defend his UFC heavyweight title in August.

Kongo is 44 and seemingly at the peak of his career. He is 8-0 since turning 40 and is a legitimate title contender for Bellator heavyweight champion Ryan Bader, a young chippy at 36.

Each fighter’s motivation to continue their careers when they are closer to qualifying for senior citizen discounts than they are to getting carded to get into a bar is different.

“I never achieved my goals,” said Sonnen, who was suspended for two years earlier this decade for testing positive for performance-enhancing drugs. “I never made it in this sport where I wanted to make it. In my last 11 fights, they were all against world champions. I beat five of those guys. But the championship wasn’t on the line. I beat all the right guys but not necessarily at the right time. And that matters to me. I’ve got the same goal as when I was nine years old and it hasn’t been achieved yet.”

“Every day, I have to wake up and beat myself,” said Machida, who lost 18 months to suspension for taking a supplement that contained the banned substance DHEA. “I know that I can achieve whatever I want to achieve. That’s what motivates me.”

Randy Couture, a six-time UFC champion, fought until he was 47. His last fight was a lost to Machida.

“It’s what you love, it’s your passion.” said Couture, now 55 and an actor and analyst for the Professional Fighters League. “We know the risks involved in this sport, but we still love this sport. We want to show everybody what we’ve worked on, what we’ve gotten good at. It’s about that passion.”

Of Couture’s 30 pro fights, 14 came after he turned 40. He won the UFC light heavyweight title twice and the heavyweight title once in that time.

Such “Life after 40” moments are not confined to MMA. Tom Brady, at age 41, won his sixth Super Bowl with the New England Patriots earlier this year. Tiger Woods won The Masters in April at age 43. Bernard Hopkins was winning boxing titles into his 50s. Mariano Rivera was saving games for the Yankees into his 40s.

There always will be such anomalies. But perhaps an athlete not competing into their 40s, assuming they want to and there are people willing to pay them, one day will become the anomaly.

“The science of athletics,” Couture said. “We’re learning how to run our Ferraris, put a little better fuel in them, take care of them a little better and make then run a little longer at fast speeds.”