Sgt. Major Carlos Ruiz shared his fitness routine for longevity at 50.
Ruiz balances cardio, resistance training, and recovery to maintain Marine Corps fitness.
He emphasizes hydration, proper gear, and adapting routines for sustained health and performance.
For every military service chief, there’s a senior enlisted advisor, the person responsible for what’s often the most human side of command, including things like troop welfare and fitness.
In the Marine Corps, that’s Sgt. Maj. Carlos Ruiz — tall, upbeat, and, at 50, still running miles alongside Marines across the globe.
While generals shape strategy and operations, senior enlisted leaders focus on how those decisions impact the troops who execute them. For Ruiz, that means staying fit and setting the example himself.
“A little bit of running, a little bit of gym, and a lot of PT with Marines,” he told Business Insider of his routine, using the military’s acronym for physical training. That “little bit of running” might be an understatement though. He recently completed the Corps’s annual marathon in Washington, DC, over 26 miles.
Here’s how the Corps’ top enlisted Marine stays in shape.
Resistance
These days, Ruiz’s priority isn’t busting records in the squat rack or leveling up in the Corps’ martial arts program. It’s longevity, something Ruiz said he’s keen to protect while still keeping up with, and often out-performing, Marines half his age.
Key to longevity is maintaining his natural build, focusing less on heavy weightlifting and more on training that builds strength without risking injury.
No longer trying to bulk up, he balances cardio and resistance work, trading heavy barbell lifts for dumbbells, kettlebells, and machines that protect his joints.
Sergeant Major Carlos Ruiz told Business Insider that fitness in the service isn’t a hobby, it’s a way of life.Lance Cpl. Ayden Cassano/US Marine Corps
Even at his rank, Ruiz still takes the Marine Corps’ two annual fitness tests, which measure both strength and endurance. The first, held in the year’s opening half, includes a three-mile run — his fastest time is about 16:30, or a 5:30-per-mile pace — along with pull-ups and a nearly four-minute plank.
The top pull-up scores for men and women are usually just over 20 and 10 dead-hang pull-ups, respectively.
The other annual test, held later in the year, simulates battlefield fitness, with 30-pound “ammo can” presses, an 800-meter sprint, and a timed agility event.
Ruiz’s wife, a retired Marine, puts him through his paces to keep his pull-ups and ammo-can lifts on point. As soon as he comes home after a long work day, he owes her a set of either, depending on which fitness test is around the corner.
“She holds me accountable at home because she’s a Marine of 22 years,” he added.
“When it’s over with the Marine Corps, I want to have another career. I’m not looking to retire out of the world,” he said, explaining he’s not one to sit still at home. “I want to be functional.”
Running
Ruiz is a religious runner.
Most days he runs a breezy five miles. On Sundays, when he’s home, he goes for a ten-mile run from his home at the Corps’ famous 8th and I barracks in Washington, DC, weaving across the National Mall, and over to the Corps’ Iwo Jima Memorial. Sometimes he spies Marine groups on the National Mall working out and pops by to say hello.
His warm-ups, a brisk walk and some stretching, are lengthier these days and an important part of his routine that he says helps to get his mind ready.
“It takes me a long time to warm up. I love the process of getting ready for a run, being alone in my head.”
Running hasn’t always come naturally, he said, and took time for him to develop a deep love for.
Bad initial experiences can lead many to dislike running, Ruiz lamented — many are thrust into the service with little prior running experience and are forced into mass-unit runs with scores of other people wearing the wrong shoes, with no coaching for form or breathing, and poor diets.
Ruiz and other Marines did a round of push-ups after a unit run in Japan on Sep. 3, 2025Cpl. Jeremiah Barksdale/US Marine Corps
It can easily morph into a short survival test for many and end there, he said. It took years for his own love of running to develop. It is now a sacred part of his daily routine.
For those looking to get into running — and who can afford new shoes — Ruiz recommends getting fitted for the right pair to maximize comfort and prevent injuries. Make running enjoyable, he said, and give it time. It might take a few months before you start to appreciate the routine that’s become therapeutic for him.
And for anyone in need of maximum Marine Corps motivation, Ruiz recommended his current running playlist of Marine and Army cadence, the songs troops call out for marching (“double time” tempo can equate to that of a leisurely jog).
Recovery
For recovery, Ruiz sticks to the basics — good food, hydration, and rest.
He knows he’ll be sluggish on his daily run if he hasn’t gotten enough water or electrolytes, or if he’s out of balance with his carbohydrate intake. An out-of-whack diet for Ruiz means “it’s not going to be a quality and a comfortable run.” Instead, he said, it’ll be one “where I spend time struggling to get a rhythm, and not relaxing.”
Ruiz is not one for trendy fitness bells and whistles except for one area — tracking his physical data like sleep, heart rate, and run times with a Garmin smart watch. It’s something special operations units already do, he said, and an effort he hopes the rest of the military can implement one day for better injury prevention. Such steps could boost retention, he said, mitigating medical issues.
“Fitness in this service should not be a hobby. It must be a way of life,” he said. “And we as a service have to provide the tools necessary for that Marine to continue to grow and get to the better version of themselves faster, and not by accident, but by design.”
Ruiz downs a protein drink after any workout, but stays away from other drinks or powders, like creatine. But especially because of his age, he said he likes to keep an open mind about trying new things when it comes to fitness, like bands for strengthening small but critical muscles that help with overall balance and strength, like hip flexors.
By 50, people are used to doing things a certain way, he said, acknowledging his own previous stubbornness with trying out new approaches to health and fitness. But now, he said, “it is rewarding to figure out a better way” of maintaining his health.
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