LA GRANGE – No one would ever know La Grange resident James Milkert, 36, is sick just by looking at him. While he appears healthy on the outside, Milkert is battling two serious illnesses, and it was his determination to take control of his health that led him to train for the Transamerica Chicago Triathlon on Aug. 28.

The Chicago Triathlon will be the second for Milkert, who has Type 1 diabetes and common variable immune deficiency. He completed his first triathlon in June in Wisconsin, after beginning his training in December 2015. And since he’s been working out, he’s never felt healthier.

“It’s been the best eight months I’ve had health-wise in the last 20 years,” he said. “I reached a point where I would either be defined by my health issues or I could try to reclaim my life and be healthier. I don’t want to be dependent on medicine.”

Milkert, who is a social studies teacher at Lyons Township High School, had been healthy and athletic his whole life, even playing volleyball at Quincy University. During his sophomore year in college, the then-20-year-old began getting very sick frequently and ended up in intensive care for a few weeks.

He said after about three years of seeing doctors, he was finally diagnosed with Type 1 diabetes and common variable immune deficiency, a rare condition in which his body doesn’t produce enough antibodies. Milkert has an insulin pump and receives an IV of antibodies every four to six weeks, which he said has made a big difference in his health. While the disorders are usually not life threatening, Milkert said he was very scared when he received his diagnoses.

“I was really confused. My family was a mess, and they still are really worried about me,” said Milkert, who is married and has a 3-year-old son.

After years of battling sinus infections and other illnesses, last fall Milkert decided to take charge of his health, and began working out with Rick Lapinski, a colleague of Milkert’s wife. Since December, Lapinski has been coaching Milkert for the triathlons. The training consists of early-morning workouts five days a week.

“He’s done a fantastic job managing everything. He knows when to push his body or when to back down,” Lapinski said. “He’s an inspiration to all people to live a healthy lifestyle, set a goal and do everything you can to accomplish it. He probably has the best attitude of any athlete I’ve ever worked with.”

Milkert’s wife, Jessica Hurt, said she’s “super proud” of her husband for taking control of his health and working toward accomplishing the goal of completing the Chicago Triathlon, although she admits she does still worry about him.

“I get nervous when he’s on a 50-mile bike ride, but he knows his body better than anyone,” she said. “It’s fulfilling for me to see him go through all the training because he’s proving to himself that he’s more than these diagnoses. He can be an athlete and have a hobby. Training gave him a purpose. It’s easy to get down on yourself or on life, but he’s one of the most positive people I know.”

While the biking portion of the triathlon comes easiest to Milkert, he admits the open-water swimming was the most difficult part during the June triathlon.

“At that point I hadn’t done all three skills back to back, and to put them together in one day was just trying to survive,” he said. “I had to monitor my blood sugar and insulin, so I didn’t care about the time, I just wanted to finish.”

The biking and swimming distances in the Chicago Triathlon will be a little longer than they were for the Wisconsin race, and Milkert said that while he’s more confident than he was before the last event, he’s still nervous for this weekend.

“I was really proud of myself because I never knew I could do anything like that. I wasn’t sure if I’d get sick afterwards, and I haven’t,” he said about the Wisconsin race. “The Chicago event will be another proving point that I’m OK. I’m just trying to be healthy and have fun. It will be cool to bike and run in the city. My next goal is to do a half Ironman next summer.”