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Gary Greenberg


February 1, 2019

How Alex Osuna Puts GRIT in Your Workout

Maybe someday scientists will come up with a pill that replaces exercise. It would be the best supplement yet, one that increases blood flow, burns fat, builds lean muscle mass, strengthens bones, releases hormones to improve mood and lower stress, detoxifies the body, aids sleep and sex, promotes healthy aging, and boosts longevity.

What you need to know

Alex Osuna is a fitness expert and a strong promoter of GRIT workouts. These are workouts that focus on the whole body instead of machine workouts which isolate muscle groups. Learn how to get some GRIT in your workout.

But that day isn't here yet, and until it arrives, people simply need to get some exercise. And that's where a guy like Alex Osuna comes in.

"Nutritionists like to say that you can't exercise your way out of a bad diet," notes Osuna, who is the managing partner of GRIT Miami, an expansive new workout facility in Florida's southernmost metropolis. "That's true, but so too is the reverse: You can't eat your way out of getting no exercise."

Osuna and partners opened GRIT in early 2018. It's not your father's gym, but rather a clean, airy, well-lit facility with plenty of room to do workouts similar to CrossFit. Its main gym is a cavernous 9,000 square feet and well-equipped with the tools of the trade: free weights, barbells, kettle balls, medicine balls, battle ropes, pull-up bars, rowing machines, air bikes, plyo (jump) boxes, gymnastic rings, and push sleds.

Woman exercising

Although GRIT is not affiliated with CrossFit, it utilizes several elements of the revolutionary workout regimen that originated in California in the late 1990s and has since evolved into its own sport.

"GRIT is a hybrid type of training," explains Osuna, 35. "We combine Olympic (weightlifting) movements with gymnastic movements and mono-structural movements (such as running, biking and rowing) to create a great overall workout."

It's a holistic, natural form of exercise.

"We don't have a lot of machines here," continues Osuna. "Machines may allow you to isolate a particular muscle group for growth and definition, but they also restrict motion. Motion is lotion. When you move, blood flows to cells to replenish them. That's why exercise is so important for longevity.

"You don't want to inhibit motion. Our ancestors weren't sitting around repeatedly lifting rocks over their heads. They were running, jumping, climbing, and hauling around carcasses on their shoulders and backs, walking up and down hills, building up core strength."

And what was good for cavemen is good for us. Numerous studies have shown that regular exercise translates into robust health and increased longevity. In one of the largest, researchers at Harvard University, the National Cancer Institute and other institutions scrutinized data from six separate surveys of exercise habits—encompassing some 661,000 mostly middle aged people—and compared them to death records for the group over 14 years.

The researchers found that even a little bit of moderate exercise, less than the recommended 150 minutes a week, lowered the risk of death by 20% over those who didn't exercise at all. Subjects who met the recommendations were 31% less likely to die. And those who surpassed 450 minutes of moderate exercise a week were 39% less likely to be pushing daisies than their sedentary counterparts 14 years later. Benefits beyond 450 minutes of exercise a week flattened out.1

So moderate exercise can have a dramatic impact on mortality risk. And it may be amplified when the exercise hits all three metabolic energy systems: phosphagen, glycolytic and oxidative.2

Group of people exercising

The phosphagen system is tapped during sudden outbursts of energy that burn the small amount of the biological fuel adenosine triphosphate (ATP) stored in muscles. It supplies explosive energy but only lasts for a few seconds.2 A 40-yard sprint or single powerlift would be good examples.2

The glycolytic system kicks in when the stored ATP is exhausted. It quickly converts glucose into ATP and lasts up to a minute before flaming out.2 Examples include a 200-meter sprint or weightlifting set.

The oxidative system is the long, slow burn of glucose and fat, and the only one of the three that requires oxygen.2 Aerobic exercises such as jogging and moderately paced biking and swimming are all examples.

GRIT workouts are designed to engage all three metabolic energy systems. And switching between them during a session, a form of high intensity interval training (HIIT), has a dramatic effect on the body.

"Combining aerobic and resistance exercises at varying intensities does the most for overall fitness," says Osuna. "You push yourself aerobically to improve cardiovascular health while the resistance exercises increase muscle and bone strength."

The science supports those claims, and more. In a landmark study published in the journal Cell Metabolism in 2017, researchers at the Mayo Clinic found that HIIT training appeared to slow down aging at a cellular level. After examining muscle cells of the exercising subjects and a sedentary control group, the scientists concluded that HIIT seemed to reverse age-related deterioration of mitochondria, the tiny organelles that power cells.3 Mitochondrial dysfunction is a key marker of cellular aging and one reason why elderly people tend to feel tired a lot. The researchers also believe that the positive changes they observed in muscle cells are likely mirrored in the cells of other types of tissue.4

"Based on everything we know, there's no substitute for these exercise programs when it comes to delaying the aging process," senior author Dr. Sreekumaran Nair (MD) declared in a statement. "These things we are seeing cannot be done by any medicine."4

So, in a way, the Fountain of Youth springs from sweat. But when pushing the body to those limits, it's important to have a training coach who recognizes weaknesses that can lead to injury. Osuna started coaching at the gyms of his uncle Mike Osuna—one of Miami's first CrossFit proponents—and later managed his relative's largest facility before striking out on his own.

"One of the first things we look at in a new member is mobility, specifically flexibility and range of motion," says Osuna, who earned a Bachelor of Science at the University of Miami, "We can see where you may have an impingement that can throw your whole system out of balance. And we devise workouts that can improve mobility and stress the body in a way that isn't dangerous.

"Everybody is different, with different strengths and weaknesses as well as different needs and goals. So you can't expect everyone to get a good result doing a cookie-cutter workout."

Even though GRIT workouts are generally done in groups, they are still individualized. People who may not be able to do regular pull-ups due to a shoulder or weight problem can instead use the low-hanging rings, where their feet touch the ground and adjusting the angle of their bodies to the floor can scale the difficulty of the pull-ups. Or, instead of running sprints, someone with achy knees can do sprints on an air bike or rowing machine.

Man lifting weights

Osuna, whose fiancée owns a physical therapy business, also incorporates elastic bands and rehab techniques.

"Physical therapy is normally used to recover from an injury, but we use it in a preventative way," says Osuna. "Why wait until you get hurt? Why not use these tools to prevent an injury?"

Adaptability and variety are two hallmarks of the GRIT workout. Members do something different every time they walk into the gym. One day they may use unevenly weighted slam balls, and the next time swing thick, heavy battle ropes. Osuna and his team of trainers vary the equipment, order of exercises, speed and number of reps, and other factors to help prevent members from falling into the rut of monotony.

"People like coming in here not knowing what to expect," he says. "It keeps them from suffering burnout."

Although Osuna doesn't focus on supplements as part of the GRIT program, he takes a few himself, including whey protein and creatine monohydrate. When training intensely, he uses beta-alanine to aid endurance. For general health, he takes turmeric for its anti-inflammatory properties and fish oil for its healthy fats.

GRIT workouts can benefit people of all ages, and its clientele ranges from pre-teens to mid-70s. Osuna explains that if people can optimize their fitness during their peak years, between the ages of 25 and 40, the decline that naturally comes with age will be delayed and take a gentler slope.

"If I see an older person who's willing to come in here and try something new, I get excited," he says. "You can teach old dogs new tricks, if they're willing to learn. And I love it when young people come in, because I know GRIT will have a lasting effect on their lives."

Osuna also prides himself in creating a sense of community, both among GRIT members and trainers. In fact, he rents out three exercise stations on a permanent basis to personal trainers who are in business for themselves.

"At one point, I was a personal trainer going from one client's home to another, and it wasn't very efficient in Miami traffic," he says. "Here, independent trainers can run their own business in a stable environment, where people come to them."

GRIT provides individual personal training for members who want it, but the main focus is on groups, which promote camaraderie. Members support and encourage each other during workouts and even socialize together. And guess what? That kind of social interaction can also increase longevity.

The ongoing Harvard Study of Adult Development initially involved some 700 men who have been followed since they were teenagers in 1938. Last year, about 60 were still alive. And researchers who analyzed data ranging from brain scans and blood tests to personal interviews, concluded that social connections appear to be good for health.5

"People who are more socially connected to family, to friends, to community, are happier, they're physically healthier and they live longer than people who are less well connected," said the study's current director, psychiatrist Dr. Robert Waldinger.6

GRIT has an area set aside for socializing, and the day Life Extension® was there, one member popped a bottle of bubbly after her group workout to celebrate a milestone in her battle against breast cancer.

"Those types of connections are very important in not only motivating people to perform their best during workouts but also in bringing a positive attitude into someone's life, whether they're dealing with things like cancer, depression, self-esteem issues or other problems," says Osuna.

In the end, it's really all about attitude, hence the name of the gym.

"It takes some grit to challenge yourself to be the best you can be," says Osuna. "Everybody has grit, and you find it by getting outside of your comfort zone and pushing yourself to the limit. When you find that grit inside of yourself, you can use it in other areas of your life. It gives you the confidence to walk into a room with a stranger for a job interview, or to make a sale, or to just do whatever it takes to achieve your goals."

Prior to the co-founding of GRIT, Alex Osuna was an educator, coached a variety of team sports, and provided private training. Visit GRIT at

If you have any questions on the scientific content of this article, please call a Life Extension® Wellness Specialist at 1-866-864-3027.


  1. Arem H, Moore SC, Patel A, et al. Leisure time physical activity and mortality: a detailed pooled analysis of the dose-response relationship. JAMA Intern Med. 2015 Jun;175(6):959-67.
  2. Available at: Accessed November 9, 2018.
  3. Robinson MM, Dasari S, Konopka AR, et al. Enhanced Protein Translation Underlies Improved Metabolic and Physical Adaptations to Different Exercise Training Modes in Young and Old Humans. Cell Metab. 2017 Mar 7;25(3):581-92.
  4. Available at: Accessed November 9, 2018.
  5. Available at: Accessed November 9, 2018.
  6. Available at: Accessed November 9, 2018.

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