Alexander Zverev, who faces defending champion Jannik Sinner in the Wimbledon final on Sunday, has been managing Type 1 diabetes since he was diagnosed at age 4, according to ABC News.
The 29-year-old German uses a glucose sensor and an insulin pen during matches, injecting insulin into the top of his thigh during changeovers when needed. He has permission from Grand Slam tournaments, confirmed by the All England Club, to check his phone on court. The phone receives readings from his glucose sensor, eliminating the need for finger-prick blood tests. Phones are otherwise prohibited on court.
Zverev disclosed his condition publicly in 2022, when he also launched a diabetes foundation focused on helping children. He had previously kept the diagnosis quiet, handling insulin injections privately during bathroom breaks if needed.
"If we as a foundation, and me just as a tennis player and somebody who has diabetes, can help even just a single kid or a single parent, I'll be the happiest person in the world," Zverev said after an early-round victory at Wimbledon. "There's a lot of great athletes, there's a lot of actors, musicians, who have diabetes. It shows that with diabetes there shouldn't be any limits."
A sensor malfunction created a serious problem at a Wimbledon warmup event in Halle, Germany. Zverev said his glucose sensor gave an incorrect reading before his semifinal match against Taylor Fritz, showing falsely high levels. He injected too much insulin as a result.
After identifying the problem, he consumed 350 grams of sugar through glucose gels in the first hour of the match to bring his blood sugar back to normal levels. He said he felt "awful" and lost the match in three sets.
Zverev addressed the malfunction at a pre-Wimbledon press conference. "The company's investigating it, looking into it," he said, referring to the sensor manufacturer. "I've been using it for 10-plus years. This is the first time ever it happened."
He also made clear he did not want the incident to discourage other diabetics from using the technology. "Those things are still very, very useful for a diabetic, make the life of a diabetic much easier than without them," he said. "It was very unfortunate for me that it happened, but I think as a product, it still is very helpful for millions of diabetes patients."
Zverev won the French Open earlier this year and is seeking back-to-back Grand Slam titles. If he wins Sunday, it would be his first Wimbledon championship.