Sasha Zverev by Luce Martini
The Alcaraz and Sinner phenomena have created a peculiar kind of atmosphere around players born in the 1990s. In particular, the rise of Sinner has drawn in a wide audience with a footballing background or, in any case, people who previously paid no attention to tennis.
To make matters worse, a number of Italian outlets that, until yesterday, gave the Big Three no more than the odd distracted article are now covering tennis around the clock — bringing in bleating journalists of questionable competence to write about the sport.
With Djokovic now taking something of a back seat as a major contender, and with Sinner suspended, Sacha Zverev stands as the current frontrunner for the world number one spot. The bitterness shown by many Sinner ultras towards Zverev is sad, though one can understand it. That of certain journalists, however, is not.
They even manage to attack something as subdued as the press conference following his 2025 defeat to Berrettini:
“I’ve not won many matches. So it’s been the worst period since my injury. I played a great first set, and once I got broken in the second set, I played 10 levels down. My ball is much slower. I stop hitting the ball. The same story the last few months. Nothing changes. So it’s me who lost the match, once again … I thought my level was terrible, but that’s just my opinion.”
Zverev has never exactly enjoyed favourable press coverage. His excesses — especially off the court — have rightly been pointed out, but more often than not, they’ve been dragged out and amplified beyond all proportion, and in contexts and ways that have little to do with tennis.
Here, we’d like to offer a different take. Granted, to those already well-versed in tennis, this article may not add much. But it’s important that it be read by the noisy newcomers.
The Invisible Opponent: Alexandr Zverev, Tennis and Type 1 Diabetes
Paris, Roland Garros 2023. The late afternoon sun lights up the red clay as Alexandr “Sascha” Zverev walks towards the bench during a change of ends. The crowd sees a top-level tennis player taking a sip of water and wiping his face; few realise that, in that very moment, Zverev is engaged in a silent, ongoing battle against an invisible opponent: type 1 diabetes.
Diagnosed at the age of three, every match he plays is also a match against his blood sugar levels. And on that surreal Parisian day, something extraordinary happens: a match supervisor tells him not to inject insulin on court, because “it looks weird” (idf.org). Zverev is dumbfounded, how can a life-saving gesture be so deeply misunderstood? He protests: “If I don’t do this, my life is at risk. What do you think I’m doing, doping? It makes no sense”.
After an initial stand-off, and thanks to the outrage sparked within the global diabetes community, the tournament organisers back down: Alexandr is allowed to manage his condition under the spotlight, as and when needed (idf.org). What at first seemed absurd ends up casting a bright light on a lesser-known reality — one made of injections, sensors, sugar, and courage. So let’s delve into Zverev’s world, and the unique challenges of competing professionally with type 1 diabetes, with a reporter’s eye and medical rigour.
Sasha Zverev by Luce Martini
Managing Insulin Under the Spotlight. Every time Zverev steps on court, he fights on two fronts: against his opponent, and against his own blood glucose. Being a type 1 diabetic, his pancreas doesn’t produce enough insulin. He therefore has to inject it manually to keep his sugar levels within a safe range.
In long and demanding matches, this means injecting insulin more than once. Before he was only allowed to do so during toilet breaks, but each player has a limited number of those. Zverev pointed out how ridiculous that was: in a best-of-five match, he might need four or five injections, but is only entitled to two toilet breaks.
For a few days, he had to improvise sprinting to the bathroom at every opportunity to administer a life-saving jab in private. A surreal image: a top athlete forced to hide in order to treat himself. “I kept going to the bathroom, but it’s not the right thing to do,” he later said.
Thankfully, the incident gained media traction. The International Diabetes Federation (IDF) condemned the episode, calling it a product of ignorance and stigma around diabetes. Under pressure, the French Open supervisors changed course: Zverev was authorised to inject insulin during changeovers, without having it count as an additional break (idf.org). “Now I can do what I need, on court and off,” he said with relief, after reaching the semi-finals in Paris.
A small but significant precedent had been set. In fact, Zverev had already been injecting insulin during changeovers in ATP tournaments, discreetly, without ever causing a stir. But each event has its own regulations, and until that point, there had been no formal clarity. Once again, he’d had to fight not just on court, but to secure a basic right: to care for himself when needed, even under the gaze of thousands.
From a medical perspective, insulin for Zverev is what water is for other athletes: essential. Without it, his blood glucose would rise to dangerous levels, leading to serious neurological symptoms, coma, and ultimately death. So it’s no surprise that Sascha has faced the issue with such determination. “Administering insulin is essential for my survival,” he explained, reminding everyone that this isn’t a matter of preference, but of survival.
It’s a delicate balance: too little insulin and his blood sugar spikes (hyperglycaemia); too much at the wrong moment, and it drops dangerously low (hypoglycaemia). During intense physical exertion like a tennis match, muscles burn glucose, yet stress hormones like adrenaline can paradoxically cause levels to rise (gssiweb.org). Diabetes doesn’t follow predictable scripts: “Sometimes during a match my levels drop, other times they go up – it depends on intensity and stress,” says Zverev.
It’s a constant act of adjustment: a few units of fast-acting insulin if sugar levels soar; a gel sachet if they drop too fast.
The Silent Companion: Glucose Sensors and Continuous Monitoring
Beyond injections, continuous glucose monitoring is the foundation of Zverev’s diabetes management. In training and daily life, he relies heavily on modern CGMs (Continuous Glucose Monitors): small subcutaneous sensors that transmit real-time blood sugar levels. As early as 2019, some observers had noticed that Zverev often looked into his bag between games, some even speculated he was checking his phone (strictly banned under anti-coaching rules at the time). In reality, he was simply checking his glucose sensor (tennis.com).
These devices are his lifeline: they allow him to know whether his blood sugar is rising or falling at any moment, and act accordingly. A CGM typically measures glucose in the interstitial fluid every five minutes, providing about 300 readings per day — effectively a continuous graph rather than occasional spot checks. This helps an athlete anticipate trends and avoid crises before they begin. If Zverev sees the sensor indicating a steady drop, he’ll take on carbs to avoid hypoglycaemia; if levels spike, he can make a small corrective insulin dose before things get worse.
Still, bringing electronic devices on court isn’t straightforward in tennis, where any kind of communication device is banned by regulation. The 2019 incident was resolved when judges were informed it was a medical device, not a phone. But the episode exposed a perception problem: to outsiders, a sensor on the arm or a glance at a receiver might look suspicious.
Zverev himself said that at Roland Garros 2023, he was told, “It looks strange when you do that on court”, as if managing one’s diabetes publicly were somehow inappropriate. Other sports have already tackled the issue. In cycling, for example, CGMs have become so common for performance optimisation that the international federation (UCI) has banned their use in races for non-diabetics, while allowing them as a medical exception for diabetic riders (medscape.com). This highlights that a glucose monitor could potentially be a performance aid for healthy athletes, but for a diabetic, it is simply part of essential treatment.
In Zverev’s case, the sensor is a silent companion: a small hi-tech patch helping him maintain balance through long, gruelling matches under the scorching sun. And by now, the tennis world has come to understand it for what it is: not an unfair advantage, but a safety measure.
Sasha Zverev by Luce Martini
The physical and mental impact of a chronic condition on court. Exchanging powerful groundstrokes for five sets under the sun is already a brutal task. Doing it while constantly monitoring your internal state adds a level of difficulty few can truly grasp. Type 1 diabetes takes its toll physically and mentally, even when well-managed.
Physically, glucose fluctuations have a direct effect on performance. Zverev has spoken openly about it: “When my blood sugar is low, you feel dizzy, and you don’t feel well… When it’s high, you feel slow, your muscles don’t respond, you feel drowsy”. It’s not just a sensation: scientifically, hypoglycaemia causes a lack of glucose supply to the brain and muscles, leading to decreased concentration, slower reaction times and loss of coordination.
One study found that young athletes with slightly below-normal glucose saw their sport-specific skills (in tennis, football, and basketball) drop by around 20% compared to when their levels were within range. It’s easy to imagine how an episode like that could decide the outcome of a fifth-set tie-break.
Severe hyperglycaemia isn’t harmless either: very high levels (above 300 mg/dl, for example) can cause dehydration, muscle cramps and a general feeling of fatigue (nfl.com). Jay Cutler, the NFL quarterback who also lives with type 1 diabetes, once described what his sugar levels were like before being diagnosed: “When you’re at 400–500 (mg/dl), you’ve got no energy, you just want to sleep. It’s tough to deal with” (nfl.com).
Zverev usually manages to avoid these extremes, but a slight miscalculation in dosage, an unexpected adrenaline spike, or a match delayed by an hour can push his glucose off track and threaten his physical condition mid-match. Every point he plays conceals an act of internal self-regulation, a fragile balance between glucose burned and glucose replaced.
Mentally, living and competing with diabetes shapes your character – for better and for worse. Zverev admitted he kept his condition hidden for years, almost out of shame or fear of appearing weak. “I was embarrassed. I always tried to hide it. I never let anyone see me check my sugar or inject myself in public – I’d always go to the bathroom,” he revealed in an interview, referring to his junior years and early career.
As a child, he was teased at school because of his diabetes, which made him retreat into himself when it came to discussing it. It’s easy to understand how this can create a psychological burden – having to appear ‘normal’ at all costs, even when you’re carrying a constant awareness of illness inside you.
The turning point came in August 2022, when Sascha decided to publicly reveal his diagnosis and launch a foundation dedicated to the disease. Since then, paradoxically, his mental strength seems to have grown: freed from the weight of secrecy, Zverev appears more serene in facing difficulties on court, and even draws extra motivation from his new role as a model for young diabetics. (pmc.ncbi.nlm.nih.gov)
“They told me I’d never become a professional athlete because of my diabetes… Now I want to prove that you can live a normal life and achieve anything with this condition,” is a message he often repeats.
What used to be a source of anxiety and insecurity has gradually become part of his sporting identity. Zverev isn’t just battling Nadal or Djokovic – he fights his own physiological limits every single day. That has given him a rare determination and resilience.
Of course, the mental strain of constantly thinking about diabetes mustn’t be underestimated. During a match, concentration can be thrown off by a flashing out-of-range reading, and the athlete has to make quick decisions – do I drink that juice now or wait? Do I give myself more insulin and risk crashing in the next set?
This kind of dual-task thinking – playing world-class tennis while acting as your own doctor – demands exceptional composure. And sometimes, when things get complicated, you can catch a glimpse of frustration in Sascha’s expression that goes beyond the scoreboard: it’s the awareness of having to fight on two fronts.
It would be easy to slip into clichés and say it has made him stronger. More likely, it has weighed on him in many moments, both on and off the court – and, as the new fans should realise, even in press conferences.
As his doctor once put it: “Managing diabetes in these conditions is like running a marathon during a tennis match – if you can do that, there’s nothing on court that should scare you.”
Between anti-doping and bureaucracy: insulin and therapeutic exemptions. There’s one last detail that makes Zverev’s story particularly unusual: the drug he injects every day is, technically, a banned substance in professional sport. Insulin is listed among the prohibited hormones and metabolic modulators by WADA (the World Anti-Doping Agency), because in a non-diabetic athlete it could, in theory, be used to enhance nutrient absorption and muscle growth (editorial.uefa.com).
For this reason, any athlete with type 1 diabetes who needs insulin must obtain a Therapeutic Use Exemption (TUE). This is an official medical certificate issued by anti-doping authorities, which confirms the athlete’s need for a particular treatment and grants permission to use a normally banned substance for health reasons.
Zverev, of course, holds all the necessary TUEs. He has provided full documentation of his diabetes – diagnosed at age three – including medical records and prescriptions, and has been officially authorised by the International Tennis Integrity Agency (ITIA) to use insulin to control his blood sugar.
In practice, this means that when he is tested, any traces of externally administered insulin in his system (or the devices he carries) are covered by these exemptions.
It’s an odd situation: Zverev is, to the untrained eye, an athlete who is “doping” – because he regularly injects a banned hormone. But in reality, he is doing so not to gain any advantage, but simply to return to baseline. His is a paradoxical condition: the same syringes that, in the hands of a cheat, might contain EPO or anabolic steroids, in his case contain the very substance that keeps him alive.
This has led to some uncomfortable misunderstandings, like the “that’s weird” incident in Paris – but Zverev handled it with calm and transparency. He declares everything. He has nothing to hide.
Each year, he must renew his therapeutic exemptions by submitting updated medical reports that confirm the diagnosis and continued need for treatment (editorial.uefa.com). WADA’s rules for type 1 diabetes typically allow for multi-year exemptions, subject to periodic reviews – for example, a TUE may be valid for up to four years, but new documentation must be filed in order to extend it.
It’s a layer of bureaucracy that, while tedious, is essential to safeguard the integrity of competition without discriminating against athletes with chronic conditions.
Alongside insulin, Zverev also has to be careful with other diabetes-related substances that might raise questions under anti-doping rules. For instance, some medications like glucagon analogues (used to treat severe hypoglycaemia), or certain ketone supplements, might look suspicious if not properly declared.
In general though, the medical and sporting communities are well aware of the distinction: an athlete with type 1 diabetes gains no competitive edge from using insulin – they use it simply to reach the same starting line as everyone else.
As the president of the IDF has stressed, “We need to break down the stigma and allow people with diabetes to manage their condition in an environment free from prejudice” (idf.org). Hopefully, incidents like the one at Roland Garros 2023 won’t happen again – and in fact, it seems that most tournaments around the world now have clear protocols that facilitate in-the-moment exemptions when needed.
Zverev himself has said he wants to work with sporting bodies to help define better guidelines. His case can pave the way and raise awareness among umpires, officials and spectators about what’s needed for diabetic athletes to compete fairly.
Gary Hall Jr
Other champions with type 1 diabetes: beyond limits, no excuses
With around 1.5 million children and adolescents (ages 0–19) living with type 1 diabetes worldwide (source: IDF), it’s no surprise that several top athletes have faced, and overcome, the same condition. Alexandr Zverev is by no means the first or only elite athlete to show that type 1 diabetes doesn’t have to stand in the way of a top-level sporting career, as long as it’s managed with discipline and knowledge. The history of sport is dotted with inspiring examples.
Take Gary Hall Jr., the legendary American swimmer. He was diagnosed with type 1 diabetes in 1999, at a time when he was already an established Olympian. Doctors told him he’d likely have to stop competing at the highest level. But Hall refused to give in. He learned to check his blood sugar every 45 minutes during training, adjusted his diet and insulin therapy, and the very next year he won Olympic gold in the 50m freestyle at the Sydney 2000 Games (diabetes.co.uk). He repeated the feat in Athens in 2004, and by the end of his career had collected ten Olympic medals – five of them gold (diabetes.co.uk). An extraordinary record for any athlete, made even more so by the fact that every stroke was also a battle for control over his own body.
Hall became one of the first athletes to prove, loud and clear, that diabetes doesn’t define what is or isn’t possible – and has since become an activist, speaker and role model for young people living with the condition.
Another striking case comes from team sports. Jay Cutler, former NFL quarterback, was diagnosed with type 1 diabetes at the age of 25, at the peak of his career, after a dramatic drop in weight and energy. Initially, he feared for his future in football. But his doctors reassured him: “You’ll be able to keep playing – you’ll just have to make some changes in how you live” (nfl.com). And that’s exactly what he did.
Cutler began monitoring his glucose during games, sipping sugary drinks when it dropped too low, and injecting insulin when it climbed. He worked closely with team trainers to align diet, training and treatment – and went on to maintain high performance levels for many seasons post-diagnosis, even coming close to reaching the Super Bowl.
Other stories include NHL player Bobby Clarke, who won the Stanley Cup in the 1970s while managing type 1 diabetes, and gymnast Charlotte Drury, who has competed for Team USA despite being insulin-dependent. These athletes all demonstrate that, with the right tools and mindset, diabetes need not limit talent or ambition.
In some cases, a shared diagnosis has even led to collective action. Professional cycling, for example, is home to Team Novo Nordisk – the world’s first all-diabetic cycling team. Competing internationally, their stated mission is to “show what’s possible with diabetes” (teamnovonordisk.com). These athletes race grueling stages while constantly checking glucose, adjusting insulin pumps and consuming carbs mid-ride – all without ever using their condition as an excuse. They ride, fight, win and lose just like everyone else, and in doing so, provide a powerful example: watching a peloton of chronically ill athletes climb mountains teaches us that limits can be pushed, especially with the help of modern medical technology.
These comparisons help put Zverev’s story in context. He’s not a medical anomaly or a one-off case – he’s part of a generation of athletes who turn vulnerability into strength. Each story is different: some use insulin pumps instead of injections, others follow stricter diets, some have more frequent glucose swings, some fewer. But the common thread is always the same: refusing to let diabetes define the limits of your dreams.
Zverev is fast becoming a symbol of this in Europe, where tennis enjoys great visibility. His decision to speak openly about the disease, after years of silence, made headlines and helped normalise a subject that’s still often hidden. Many young fans with diabetes now see him as an idol they can identify with – and he’s embraced the role wholeheartedly.
The courage of a champion, the hope of many
The word “heroic” is often overused in sport. But in Zverev’s case, heroism feels real – quiet, human, everyday. His perseverance in turning a chronic condition into a routine part of life, integrating it seamlessly into the career of an elite athlete, without using it as an excuse or a weapon, is powerful.
Like a tightrope walker, Sascha maintains balance between health and competition, reminding us that behind every great champion there is also a vulnerable human being. His aggressive, powerful playing style coexists with delicate, precise actions: calibrating insulin doses, unwrapping a glucose gel mid-set. This duality forms the rich narrative of his career.
Today, Zverev steps on court with a newfound awareness and a calm hard-won over time. “I can do whatever I need, whenever I need,” he says about his diabetes. And that phrase – whether referring to an injection during a changeover or a down-the-line winner – is the motto of his reclaimed freedom.
Sasha Zverev by Luce Martini
Through the Alexandr Zverev Foundation, created in 2022 following his public revelation, he is committed to providing insulin and diagnostic tools to underprivileged children in developing countries, so that no child is forced to give up their dreams because of lack of treatment.
And so, the circle closes: the boy who was once told “you’ll never play sport at a high level” has become a man who inspires thousands of children not to give up.
In an era of supercoaches, obsessive athletic preparation and mental performance consultants for marginal gains, Zverev’s story reminds us of a simpler truth: passion and courage can move mountains – and defeat opponents you can’t even see.
His racquet strikes the ball with the same force with which, metaphorically, it strikes down clichés about diabetes. Every one of his victories, every ace, counts not just for the ATP rankings, but for something bigger: to prove that type 1 diabetes can be faced head-on – without clipping the wings of those who dream of flying high.
If someone were to write a book about him, they might imagine a metaphorical tie-break – between man and condition. On one side, diabetes, trying to sap his strength at key moments; on the other, the iron will of an athlete who refuses to give in.
And at the end of the story, they’d likely write about a young man who doesn’t make excuses, but only seeks victories – on the tennis court and in life. Because watching Zverev lift trophies, after watching him battle himself, is the clearest proof that a diagnosis is not a destiny.
References
- International Diabetes Federation – “IDF response to Zverev incident at French Open 2023” (09 June 2023)idf.orgidf.org.
- Tennis.com – “Alexandr Zverev opens up about diabetes struggles at Roland Garros” (Baseline, 08 June 2023)tennis.comtennis.com.
- Sportskeeda – “I was embarrassed of it… playing tennis with Type-1 diabetes” (intervista, 09 June 2024)sportskeeda.comsportskeeda.com.
- WADA – “TUE Physician Guidelines: Diabetes Mellitus” (Version 5.0, March 2022)editorial.uefa.comeditorial.uefa.com.
- Riddell MC et al. – “The competitive athlete with type 1 diabetes” (Open Access J Sports Med, 2020)pmc.ncbi.nlm.nih.gov.
- Kelly D. et al. – “Blood Glucose Levels and Performance in Adolescents with T1DM” (field study, Int J Pediatr Endocrinol 2010)pmc.ncbi.nlm.nih.gov.
- NFL.com – “Cutler has Type 1 diabetes, career not in jeopardy” (May 2, 2008)nfl.comnfl.com.
- Diabetes.co.uk – “Gary Hall Jr. – Olympic Medalist with Type 1 Diabetes” (15 Jan 2019, updated 29 Oct 2023)diabetes.co.uk.
- Team Novo Nordisk – “All-Diabetes Pro Cycling Team” (officicial site, 2023)teamnovonordisk.com.
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