LONDON — When Alexander Zverev steps onto the court Sunday for the Wimbledon final against defending champion Jannik Sinner, he’ll be facing more than just a tough opponent. The 29-year-old German tennis star also manages Type 1 diabetes, requiring him to keep a close eye on his blood sugar and sometimes inject insulin right there on the court during match changeovers.
Zverev, who claimed the French Open title and is now chasing back-to-back Grand Slam championships, uses an insulin pen to administer injections to his thigh during breaks in play when necessary.
He first revealed his diagnosis publicly in 2022, though he had lived with the condition since he was 4 years old, according to his diabetes foundation. Before going public, Zverev handled insulin injections quietly during bathroom breaks so no one would notice.
His public announcement came alongside the launch of his foundation, which focuses on helping children affected by diabetes.
“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 following an early-round win 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.”
Zverev’s condition created a serious problem at a pre-Wimbledon warmup tournament in Halle, Germany. During his semifinal match against Taylor Fritz, his glucose sensor gave him a faulty reading — showing falsely elevated levels — which led him to inject more insulin than he actually needed.
Once he realized what had happened, Zverev consumed 350 grams of sugar through glucose gels within the first hour of the match in an attempt to bring his blood sugar back to a safe level. He described feeling “awful” and went on to lose the match in straight sets.
“The company’s investigating it, looking into it,” he said at a press conference ahead of Wimbledon, referring to the manufacturer of the sensor. “I’ve been using it for 10-plus years. This is the first time ever it happened.”
Despite that frightening incident, Zverev was quick to defend the technology overall.
“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.”
Grand Slam tournaments, including Wimbledon’s All England Club, have granted Zverev special permission to use his phone during matches to monitor his glucose readings. His sensor transmits data directly to the phone, eliminating the need for finger-prick blood tests. Phones are not otherwise permitted on court.
Zverev is far from the only elite athlete to compete at the highest level with Type 1 diabetes. NHL Hall of Famer Bobby Clarke played his entire professional career with the disease, and current NHL player Max Domi also has the condition. Baltimore Ravens tight end Mark Andrews, who was diagnosed as a child, regularly checks his blood sugar during games. Former NFL quarterback Jay Cutler received his diagnosis in his mid-20s, as did Olympic gold-medal swimmer Gary Hall Jr.
Advocates stress that visibility matters — both in sports and beyond. Last year, Mattel unveiled its first Barbie doll representing a person with Type 1 diabetes, complete with a continuous glucose monitor on her arm and a phone showing a diabetes management app.
The disease was once commonly called “juvenile diabetes” because it tends to develop in children and teenagers. The International Diabetes Federation estimates that approximately 9.2 million people worldwide are living with Type 1 diabetes.
According to the U.S. Centers for Disease Control and Prevention, the disease occurs when “your pancreas doesn’t make insulin or makes very little insulin.” Insulin is essential for allowing blood sugar to enter the body’s cells for energy. Without it, blood sugar builds up dangerously in the bloodstream, making insulin injections a daily necessity for those with the condition.
