Joe Robles joined the Army as an enlisted man, serving in an artillery unit in Vietnam, and went on to command a major force during Operation Desert Storm.

He retired as a two-star general following a 28½-year military career, and then climbed the executive ranks at USAA to lead the San Antonio-based insurance giant as CEO. He strengthened the company’s performance, became a favorite among USAA employees and served as a model corporate citizen.

Today, he struggles with something as mundane as buttoning his shirt.

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Wednesday, before a gathering at the Warm Springs Rehabilitation Hospital of San Antonio on Medical Drive, Robles revealed he has Parkinson’s disease.

“Buttons are hard because they truly require energy to put ’em in that hole and tighten down,” he said after a presentation to fellow patients. “Parkinson’s really degrades your ability to do fine motor skills.”

Robles, 73, wasn’t diagnosed with Parkinson’s until after his retirement from USAA in 2015, but he suspects he’s had it for as long as nine years. Just before his retirement, he attributed a noticeable tremor in his left arm to a rotator-cuff injury.

“I just didn’t accept it mentally,” Robles told a group that included others who have the disease.

The unassuming Robles, who had a 20-year career at USAA, including about seven years at the helm, decided recently to go public with his diagnosis.

“I want people to understand there’s a lot of people with Parkinson’s,” he said during an interview. “Do the math. The (aging) of the baby boom generation is going straight up. With them, there will be a higher percentage of them diagnosed with Parkinson’s.

“And the sooner they know about it and are not as scared about it, the more opportunity and treatment they can be given,” he said.

April is Parkinson’s awareness month and Robles spoke at an event highlighting how patients can manage their Parkinson’s with education, therapy and technology.

Parkinson’s is a neuro-degenerative disorder that has no cure. Patients may experience tremors, gait and balance problems, slowness of movement and limb rigidity.

Almost 1 million people in the U.S. will be living with the disease by next year, according to the Parkinson’s Foundation’s website. About 60,000 individuals are diagnosed each year. An estimated 50,000 in San Antonio have the disease. Actor Michael J. Fox and singer Neil Diamond are among those living with Parkinson’s.

Robles recently completed one-on-one therapy, a task made harder by a broken hip he sustained when he fell in December. The tumble had nothing to do with his Parkinson’s, he said.

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This week, Robles started participating in a Parkinson’s Outreach Program with other patients. They exercise as a group and play Wii video games.

It’s a far cry from his days at USAA, where he oversaw unprecedented increases in membership, assets and net worth at the company. It provides insurance, banking and financial services to members of the military, veterans and their families.

It was Robles who made the decision to open USAA’s membership to all who have honorably served. He also was credited with fostering a culture of technological innovation. It reportedly was the first institution to give customers the ability to deposit a check into their bank account using a smartphone. The number of USAA-held patents jumped from five to 558 during his watch.

It wasn’t until Robles left USAA that he started to question whether the arm tremors were really due to a rotator-cuff problem. He went to a neurologist “who knew her business,” he said.

“Research says that patients with Parkinson’s do not come out right away,” said Melinda Rodriguez, senior executive director of business for AQTS Home Health, one of the sponsors of the event.

“People just think, oh, it’s old age. Oh, it’s just tremors,” Rodriguez said. “They don’t really go to doctor.”

Donning a red and black Adidas warm-up jacket and black jeans, Robles spent part of his presentation urging fellow patients to “exercise, exercise, exercise.” Exercise can have a positive impact on Parkinson’s symptoms.

During a question-and-answer session, Robles was asked how long he’ll be able to continue doing the things he’s accustomed to doing.

“I believe that I’ll be able to do a lot things that I’m doing today, and more,” Robles replied. “But I am taking it seriously. I’m going to training, I’m going to work with people who help me.

“I don’t hide my head, I don’t feel ashamed,” he added. “I’m going to exercise, exercise, exercise, to keep myself active, limber, flexible and all the words that you read about.”

“Keep going,” another patient shouted.