Health: Keeping it up

Understanding how Viagra works could help your cycling (Roland Magunia/AFP/Getty Images)

While Viagra is well known as a performance-booster off the bike, understanding the way it improves blood flow – not the Viagra itself – could help cyclists gain extra speed.

In June last year, Italian police found 82 pills hidden in toothpaste tubes in the car driven by the father of Gerolsteiner rider Andrea Moletta. Moletta was later suspended by his team for suspected doping, but the police could not prosecute the rider on the basis of the pills because they were perfectly legal. They were Viagra.

It’s possible that Moletta – or his father – was using the Viagra for the reasons with which the drug is most commonly associated. But more and more evidence is starting to suggest that Viagra may be performance-enhancing when used at altitude.

Testing the science of Viagra

A team of scientists from Stanford University and the Veteran Affairs department of the Palo Alto Health Care system carried out an experiment in which cyclists completed an identical time to exhaustion test at altitude with and without Viagra, or sildenafil as it’s known in scientific circles. On average, performance was improved when taking Viagra by a whopping 15 per cent. But the average result masked what was really going on.

Some responded to the Viagra in an incredibly positive way, recording a 39 per cent average improvement, while others found no improvement or even a slight decline in performance.

Why Viagra is not recommended for sports people

One reason might be susceptibility to side effects. When taking Viagra some of the cyclists in the study said they suffered from headaches, a flushed face and blue-tinged vision. One individual had to withdraw from the trial altogether because of the severity of the headaches. Even some who improved said they felt more fatigued and less able to focus when taking the drug. Anne Friedlander, who was part of the research team, believes this could be due to the Viagra making them push too hard.

 “The improved performance could cause side effects from over exertion at altitude beyond what the body would normally be prepared to do,” she said. “There could also be side effects we don’t even know about resulting from the changes in the direction of blood flow to less optimal tissues.”

For this reason Friedlander and her co-researchers do not recommend Viagra as a performance-enhancing drug for sports people, especially given their experiments also showed it didn’t improve performance at sea level.

Blood-pumping good news

Although Viagra might not be suitable for cyclists because of its possible side effects, understanding the science behind it certainly could be.

Viagra has the effect of widening blood vessels and attacking the plaque-like patches that build up inside arteries and attract cholesterol. These cause heart disease and high blood pressure, and also prevent oxygen transferring as easily from the lungs into the arteries. Viagra was in fact originally developed as a drug to reduce blood pressure, before its other qualities were discovered.

“The hypothesis is that Viagra widens the pulmonary vessels, thus allowing more blood to leave the heart,” said Friedlander. “It also removes the ‘patchiness’ which means more oxygen can pass from the lungs into the blood. More oxygen in the blood plus more blood being pumped means more oxygen reaching the tissues and increased performance.”

In the study, the cyclists who responded well to Viagra found the drug increased the amount of blood pumped from their hearts by 25 per cent at rest and 32 per cent during exercise. Stroke volume, the amount of blood pumped with each contraction of the heart, was also significantly increased. So the Viagra partly counteracted the effects of altitude – lack of oxygen – and meant that blood flow was not reduced by nearly as much as it normally would have been.

This also explains why Viagra is not effective at sea level. It’s only when blood flow from the heart is reduced that it can help. At sea level, pulmonary constriction is not limiting to performance because oxygen is so plentiful that the red blood cells, which transport the oxygen round our bodies, get completely saturated with oxygen whether our arteries are constricted or not. It is only when the air is thin and oxygen is less abundant that widening the arteries has an effect.

Attacking the problem with natural solutions

Cyclists are better known for attacking the problem of improving blood circulation – and hence performance – from the opposite angle. Rather than widening arteries to let more oxygen be transferred and more blood to flow, they’ve found ways to get the body to produce more of the oxygen-carrying red blood cells.

To do this you need more of the hormone erythropoietin (EPO), which stimulates the production of red blood cells. This can be done naturally – and legally – by altitude training: the brain recognises that there is less oxygen available and therefore produces more EPO to compensate; or it can be done illegally, as the sport of cycling knows only too well, by simply injecting the EPO.

But that doesn’t mean cyclists can’t also look at ways to widen and clean up their arteries too. After all, it’s good for preventing heart disease as well as for cycling performance.

Garlic is often called the natural Viagra as it contains a substance called allicin which improves blood flow. It’s also an anti-oxidant meaning it attacks the patches of cholesterol that build up. A joint study by researchers from Oxford and the US found that 261 subjects who took a garlic supplement for 12 weeks reduced their cholesterol level by 12 per cent.

Other foods high in antioxidants like broccoli and berries will do likewise. Similarly, Omega 3s, those helpful unsaturated fats contained abundantly in nuts and oily fish, have many healthy properties, and one in particular is to thin the blood, making it flow more easily and meaning those plaque-like patches don’t form.

Of course, the most effective way for a cyclist to improve blood flow and performance is through training. Standard training techniques work on all the aspects of blood circulation discussed here, and in general do so far more effectively than Viagra or any other supplement is ever likely to. So, until you feel you’ve trained all that you possibly can, you can probably go on deleting those Viagra spam emails just a little while longer.  

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