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Study finds paracetamol helps cyclists' endurance - but health and ethical questions arise

Earlier study said painkilling drug could shave 30 seconds off 10-mile time trial

A recent study suggests  paracetamol can help improve the performance of cyclists. The painkiller is not currently on the Prohibited List of the World Anti-Doping Agency (WADA) – but the academic who led the study says the agency should rethink its position. An earlier study found that taking the drug could shave 30 seconds off a 10-mile time trial.

Separately, concerns have been raised about people overdosing on paracetamol as a result of regular and excessive usage of the drug, plus the fact that in a sporting context it pushes ethical boundaries and may lead to athletes going on to take prohibited substances.

The study, carried out at the University of Kent, and published in September in the journal, Experimental Physiology, found that taking paracetamol, which also works as an anti-inflammatory, helped endurance by reducing pain and that physical exertion could be maintained on for longer in hot conditions.

It involved 11 men described as “recreationally active participants” participating in time-to-exhaustion trials on a stationary bike after taking either a placebo or paracetamol –known as acetaminophen in some countries – in temperatures of 30 degrees Celsius.

Findings that taking paracetamol improved the endurance ability of the riders who had taken it is an issue that anti-doping authorities need to address, said Dr Lex Mauger, who led the study at the University of Kent’s School of Sport and Exercise Sciences.

He urged that “consideration by the World Anti-Doping Agency (WADA) and local anti-doping authorities should be made about the use of non-steroidal anti-inflammatory drugs (NSAIDs) in sport – on both health and performance grounds. Secondly, the utility of paracetamol as a first-response drug to exertional heat illness should be investigated."

Dr Mauger added: "Whilst we have found that paracetamol improves the time someone can exercise in the heat, and that this occurs alongside a reduced body temperature, we did not measure the specific mechanisms by which this may have occurred. It is important now to try and isolate how paracetamol reduced participants' body temperature during exercise."

The earlier study, conducted by researchers at the University of Bedfordshire and published in the Journal of Applied Physiology in July 2009, analysed the performance of 13 competitive cyclists recruited from local clubs.

Following initial assessment, the participants returned to the laboratory on two separate occasions to ride a 10-mile time trial, using their own bikes on a RacerMate turbo trainer.

On each occasion they were given three capsules, either containing a placebo or paracetamol, which is known as acetaminophen in some countries and referred to by that name in the study. Total dosage was 1.5 grams on each occasion.

Besides the 30-second average improvement in time – 26 minutes 15 seconds with paracetamol compared to 26 minutes 45 seconds with the placebo – there was also a higher power output during the middle part of the time trial.

Although there was no reduction in perceived pain among those administered paracetamol, something that conflicted with researchers’ expectations, those participants did say that they found riding the time trial “easier” or “better.”

But experts have warned that if not taken as directed, paracetamol can lead to health problems including liver failure and even death through non-deliberate overdose, as well as potentially provoking severe allergic reaction.

A study led by Dr Kenneth Simpson, of Edinburgh University and the Scottish Liver Transplantation Unit in 2011, which analysed 663 patients admitted to Edinburgh Royal Infirmary for liver damage resulting from paracetamol warned of the danger of “staggered overdoses.”

That refers to patients where the hospital admission was not due to a deliberate overdose, but where instead the harm was done as a result of gradual build-up of using the drug more regularly and in greater dosage than directed.

In all, 141 of the patients analysed had taken a staggered overdose as they sought to combat the effects of conditions such as toothache or persistent headaches.

Dr Simpson said: “They haven’t taken the sort of one-off massive overdoses taken by people who try to commit suicide, but over time the damage builds up and the effect can be fatal.

“They are often taking paracetamol for pain and they don’t keep track of how much they’ve consumed over a few days.

“But on admission, these staggered overdose patients were more likely to have liver and brain problems, require kidney dialysis or help with breathing and were at greater risk of dying than people who had taken single overdoses.”

Earlier this year, a New Zealand cyclist with hopes of becoming a professional openly admitted using paracetamol during races – something that is entirely permitted under current anti-doping rules.

The rider, Alex McGregor, a 23-year-old who spent four years based in Belgium and was linekd to a US-based team until its sponsor got cold feet in the wake of the Lance Armstrong scandal last year, confessed “it’s not a good look” to be taking tablets prior to the start of a race.

"A lot of people think your taking it to work like a drug or enhance performance, but it doesn't really do that," said McGregor, quoted on

"I can see the effects of using paracetamol, for example, it stops . . . you don't feel the pain, as such. You don't feel that real heat.

"There's been times on a road race where I've found it really beneficial, like a cold, shitty day, where the legs are cold but hurting as well. You can feel the painkiller working, but you've got to have the dosage right, because when it wears off, you notice it.

"I'm looking into it with a sport scientist here in Dunedin," he added

The head of Drug Free Sport New Zealand, the national anti-doping authority, Graeme Steel, warned that even drugs that aren’t banned by WADA could give rise to concern.

He said: "Athletes begin on the road to doping by doing things that are technically permitted, but really are on the verge of unethical behaviour."

"It's something we would prefer athletes didn't do," he went on.

"We really have no jurisdiction over it in one sense, but one of the things that concerns us is that athletes begin on the road to doping by doing things that are technically permitted, but really are on the verge of unethical behaviour."

Simon joined as news editor in 2009 and is now the site’s community editor, acting as a link between the team producing the content and our readers. A law and languages graduate, published translator and former retail analyst, he has reported on issues as diverse as cycling-related court cases, anti-doping investigations, the latest developments in the bike industry and the sport’s biggest races. Now back in London full-time after 15 years living in Oxford and Cambridge, he loves cycling along the Thames but misses having his former riding buddy, Elodie the miniature schnauzer, in the basket in front of him.

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