5 barely legal performance enhancers pushing Olympians to the edge

5 barely legal performance enhancers pushing Olympians to the edge

From caffeine, to carbon monoxide rebreathing, here's what could be banned at the next Olympics.

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Photo credit: Getty

Published: August 3, 2024 at 7:15 am

In 1999, sports changed forever. On 10 November, WADA, the World Anti-Doping Agency, was established “to protect athletes, promote the values of clean sport and preserve the spirit of sport internationally”.

Its formation came off the back of numerous high-profile drug-fuelled incidents, including Ben Johnson’s 1988 steroid-injecting stride to 100m Olympic gold and the 1998 'Festina Affair', where a host of drugs was discovered in the boot of a team’s car at the Tour de France. With concern for athlete health – and the concern that viewers would turn off professional sport in their droves – WADA was formed.

Under the WADA Code, they issue an annual list of prohibited substances and methods, known as the ‘prohibited list’, which covers both in- and out-of-competition use. Prohibition comes if a substance or method satisfies two of the following three criteria:

  • It has the potential to enhance sports performance
  • It represents an actual or potential health risk to the athlete
  • It violates the spirit of the sport

Overall, this makes a safer environment for the athlete. But it also creates a grey area where some substances or methods might be deemed legal even if there’s a case for illegality.

To that end, we dig deep into completely legal methods and substances that are commonly used by professional athletes but could be banned in future.

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1. Carbon monoxide rebreathing

Over 100 people die each year in the United Kingdom from carbon monoxide poisoning, often from faulty gas boilers. So, on the face of it, it seems somewhat surprising, if not rather dangerous, that carbon monoxide ‘rebreathing’ is commonplace.

“We’ve been using it in sport science for years to measure an athlete’s haemoglobin mass,” says Dr Laura Lewis, director of science at USADA (United States Anti-Doping Agency).

“Athletes inhale a bolus of carbon monoxide – around 1.25ml per kilogramme of bodyweight – from a glass-like spirometer, which looks a little like a flute with a big bag at the end. You’re rebreathing through this closed circuit for a two-minute period. In that time, the carbon monoxide’s mixed into your system and the result is you can measure a number of blood parameters like haemoglobin mass.”

Haemoglobin mass is essentially a proxy for the body’s total amount of red blood cells – and the higher the mass, the more oxygen you have to fuel working muscles.

Conceptual illustration of red blood cells (erythrocytes) with oxygen molecules (white) in an artery.
Carbon monoxide breathing can raise the carbon monoxide levels in your blood to around 5 per cent. - Photo credit: Getty

Athletes who train at high altitudes tend to create more red blood cells in a desperate search for more oxygen. It also means that when they’re back at sea level, they can perform better for longer.

However, carbon monoxide rebreathing isn’t just the gold standard to measure the impact of altitude. If inhaled regularly, it can actually replicate the effects of attitude, too.

That’s because carbon monoxide binds to haemoglobin with 240 times the affinity of oxygen. This bond can last for several hours, reducing blood's ability to carry oxygen. In response, the body produces more red blood cells to find more oxygen. Cue increased haemoglobin mass.

WorldTour cycling teams UAE Team Emirates and Visma-Lease a Bike have confirmed they use the carbon-monoxide rebreathing method as a measuring tool and many of their riders are at the Olympics. They’ve stated they don’t use the more aggressive approach for performance purposes.

We contacted WADA for their views. A spokesman told us, “Exposure to carbon monoxide has been discussed by WADA’s Prohibited List Expert Advisory Group but there is no consensus on whether it can have a performance-enhancing effect and no sufficiently robust data currently supports that proposition. It is, however, generally acknowledged that it can be dangerous to use so it would not be recommended.”

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2. Oxygen tents

Similar to the carbon-monoxide rebreathing, many athletes replicate the oxygen-deprived environs of high altitude in an effort to boost red-blood-cell count in hypoxic chambers, also known as ‘oxygen tents’.

Many can be found in London's The Altitude Centre, whose Olympic client list includes United Kingdom Athletics, plus Premier League clubs Manchester United and Tottenham Hotspur.

Athletes can either train at the Altitude Centre or rent out portable training units ­– a mask, tube and mini-generator – that mimic altitude, or sleep in altitude tents, where a generator sucks out oxygen.

They came to prominence in the early 2000s when Canadian cyclist Genevieve Jeanson blamed the use of the tents for a failed doping test, which showed an unusually high red blood cell count. “I intend to review my use of an oxygen tent, based on appropriate professional advice,” she said in 2003. “I've used the tent for four years and I've come to believe that it does me good.”

Graham Cooper is using altitude training, also known as hypoxic training.
Former footballer Graham Cooper exercises with a training mask connected to an altitude generator for low-oxygen training. - Photo credit: Getty

This ‘artificial’ raising of blood parameters is questionable as it’s very hard for doping agencies to unpick. There’s also an argument it’s against the ‘spirit of sport’, which WADA stated in 2006 but didn’t add them to the prohibited list. “It doesn’t mean we approve them,” then WADA head Dick Pound said at the time.

Italy took it upon itself to ban altitude tents, giving their athletes a potential disadvantage. However, they lifted the ban earlier this year.

3. High-tech tri suits

Alex Yee of Team Great Britain competes during Men's Individual Triathlon on day five of the Olympic Games Paris 2024
Alex Yee overtook New Zealand's Hayden Wilde in a dramatic finale to the triathlon at the Paris 2024 Olympics - Photo credit: Getty

British triathlete Alex Yee was rightly lauded for his stunning performance at the Paris Olympics, which saw him coming back from 15 seconds behind to take the gold. But alongside his late surge, commentators also highlighted his cutting-edge trisuit developed by the UK Sports Institute.

The trisuits reportedly draw on aerodynamic technology that’s helped British Cycling to top the Olympic medal charts since 2008. However, they can also be tweaked to give triathletes extra help in the water. At this moment, we know very little. But we do know they’re pushing the regulations.

“I can’t say too much, but we’ve spent the last three or four years developing suits that have as much of the body right up to the edge of the rules covered up as you possibly can,” British Triathlon’s performance director Mike Cavendish told The Guardian.

“If you know anything about cycling, the more you can cover up the skin, the better. The sport’s rules are pretty restrictive, but we found some interesting things we can do around that, and the type of ­material we use.”

Material, seam placement and fit are big subjects in sports clothing where innovation can be the difference between victory and defeat. The surface of the material is particularly important, and we know these suits feature ridges that create a turbulence effect in the suit to cut wind resistance and drag.

The suits are also custom-made with Brit triathletes undergoing a 3D laser scan before they’re built with polyurethane derivatives. How effective the trisuits are remains to be seen.

If they are successful, could they end up the way of the Speedo LZR Racer? At the Beijing Olympics in 2008, 94 per cent of all swimming races were won by athletes wearing Speedo’s LZR racer swimsuits. After 17 world records fell at the European Short Course Championships later that year, the International Swimming Federation (FINA) effectively banned them, changing its rules regarding the length and material of swimsuits.

4. The ketone drink

To an athlete, ketones are key. Produced by the liver from fats, they serve as an energy source predominantly when the body’s in a state of starvation. A study at Oxford University observed that creating a ketone drink taps into this ‘fasted’ energy when not starved, potentially conserving precious glycogen supplies (carbohydrate stores in the body) for intense hard athletic efforts.

Later research showed that consuming a ketone drink reduces the levels of the hormone ghrelin, which is involved in appetite regulation, and so inhibits the desire to eat.

In fact, over 70 studies suggest ketones can also improve brain health and cognitive performance, boost endurance, help you sleep better and accelerate recovery between hard exercise sessions.

It’s the wonder drug that’s currently legal and is used by many athletes including Belgium’s Remco Evenepoel, who won Paris Olympic gold in the cycling time trial.

Why we say “currently legal” is that ketones aren’t used by all. The Movement for Credible Cycling (MPCC) is an organisation set up in 2007 to promote the idea of clean cycling. It’s a non-mandatory organisation that eight WorldTour teams (cycling’s first division) have signed up.

The MPCC’s stance on the ‘legal’ wonder drug is “to commit to the idea of non-use”, as, they say, the lack of research into its long-term effects one of the MPCC’s major concerns.

In other words, their members shouldn’t use it. In the short-term, they cite concern that athletes might vomit and encourage more studies to be carried out into ketones and its impact on health.

5. Caffeine

To this day, caffeine is the one of the most effective nutritional supplements.

Why is down to numerous studies showing caffeine’s ability to improve performance whether it’s increasing fat burning and speed, or lowering the perception of effort. How is through being a master of disguise.

In the brain, adenosine acts as an inhibitory neurotransmitter, meaning it promotes sleep and suppresses arousal. But when adenosine-lookalike caffeine is in town, nerve activity increases rather than slows down.

The pituitary gland in the brain senses this neuron activity, perceives it as an emergency and so releases hormones that directs the adrenal glands to produce adrenaline, which stimulates the fight or flight response of increased heart rate and blood pressure. For an Olympic footballer, say, the result is an increased ability to repeatedly sprint at near maximum for more of the 90 minutes.

How much caffeine the athlete should consume depends on the desired effect. If it’s muscular, like in preparation for a sprint, you’d need a significant amount, around 3-4mg caffeine per kilogramme of bodyweight. That’s around 200mg (two cups of coffee) for a 60kg footballer. If it’s for endurance, 110-150mg is deemed sufficient.

So proven are caffeine’s performance benefits that WADA (World Anti-Doping Agency) prohibited its use above a certain concentration until 2004, but reportedly declassified it because of its ubiquity in the food supply and difficulty in enforcing sanctions.

Why the ban arose is from evidence that caffeine is not only a performance enhancer but possibly unsafe, too, especially when used for a long time or in doses over 400mg daily. Caffeine can cause insomnia, nervousness, restlessness, nausea, increased heart rate and other side effects.

Larger doses might cause headaches, anxiety and chest pain. In short, excess caffeine consumption is deemed unhealthy.

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