​Many readers have asked why Alexander Zverev has been seen using his phone multiple times during matches at Wimbledon this year, despite a general ban on players handling devices on court. The answer lies in Zverev’s medical condition: he is a type 1 diabetic, and he operates under a medical exemption that allows him to use a phone on court to monitor glucose levels and manage insulin as needed.
The All England Lawn Tennis Club (AELTC) has confirmed to BBC Sport that Grand Slam events maintain a roster of players with diabetes who receive permission to use their phones during matches for glucose monitoring and insulin administration when required. Zverev, who has progressed to the men’s singles final, explained to BBC Sport that he owns two phones, one of which is non-SIM and dedicated solely to displaying data from his continuous glucose monitor (CGM) on court. This setup enables him to read his glucose readings directly from his phone screen rather than performing repeated finger-prick checks at every changeover.
“That’s why the umpires allow me to check my phone, so I don’t have to poke my finger every changeover,” he remarked.
Earlier this year, during the Halle Open in June, a malfunction with Zverev’s glucose monitor caused him to administer an insulin dose far higher than necessary in his semi-final defeat to Taylor Fritz. He said the error left him feeling “absolutely terrible,” requiring him to ingest roughly 350 grams of sugar to counterbalance the excessive insulin dose.
Zverev’s on-court phone use has been visible at Wimbledon as he monitors his insulin levels in real time. For players without medical exemptions, however, Wimbledon and the LTA impose strict rules. Phones must be switched off and stored away before stepping onto the court, kept out of sight from both players and umpires, and examples of a complete prohibition on smartwatches or similar devices on court are common across tournaments.
In some events, athletes have also been instructed to remove fitness trackers. Violations of these rules can result in immediate dismissal from the competition and may trigger a formal investigation by the appropriate officiating body, which could lead to sanctions or more serious disciplinary action.
This story is part of BBC Sport’s Ask Me Anything series, a collection of practical explainer features. The series covers a range of Wimbledon-related topics, from the reasons for empty seats on show courts to whether umpires can take toilet breaks, how heat rules are applied at the event, and how celebrities are invited to Wimbledon’s royal box. The aim is to provide readers with clearer insight into the tournament’s procedures and controversies, while highlighting the specific policies that affect players who live with diabetes.
At Wimbledon, the use of medical exemptions underscores the delicate balance between tournament rules designed to ensure fair play and the exceptional needs of athletes who manage chronic conditions on a high-stakes stage. As Zverev continues to compete at the highest level, his case illustrates how adaptive regulations can accommodate essential medical monitoring without compromising the integrity of the sport. Fans and followers can expect continued coverage of how such exemptions are implemented in practice across Grand Slam events, and how officials evolve policies to support athletes with diabetes while maintaining consistent enforcement for all competitors.