Professional cycling is chaotic and edgy, thrilling and petty, and often dysfunctional. With recent reports that the erectile dysfunction treatment, Viagra, may improve performance on the mountain stages, there may be yet another drug scandal poised to hit future races.

Running from Saturday July 7th to Sunday July 29th 2007, the Tour de France is made up of a prologue and 20 stages and covers a total distance of 3,550 kilometres. All over Europe, and indeed the world, people marvel at the dedication, endurance, athleticism and pain thresholds the riders displayed over the three weeks. However, the world of professional cycling is rife with drug scandals. A sad fact that has led many to doubt whether or not the physical feats they see in a bike race are real.

Doping has been a problem in cycling for a long time (it actually dates back to the early days of the last century when cocaine was used as a stimulant). Here are just some of the scandals that have hit headlines in recent years.

• The pre-race favorite to win this year's Tour, Alexandre Vinokourov, was kicked out of the competition after testing positive for blood doping
  
  
• The race leader, Michael Rasmussen, was kicked out of the Tour de France by his Rabobank team, during the 2007 race.
  
  
• The winner of the 2006 Tour, Floyd Landis, tested positive for performance enhancers and is awaiting an arbitration decision on his case.
  
  
• The winner of the 1999-2005 Tours, Lance Armstrong, never tested positive but a recently published book nonetheless claims he took performance enhancers (an allegation Armstrong vehemently and litigiously denies).
  
  
• The winner of the 1998 Tour, Marco Pantani, is dead of a cocaine overdose.
  
  
• The winner of the 1997 Tour, Jan Ullrich, retired this year after being banned from last year's race in the Operacion Puerto doping scandal.
  
  
• The winner of the 1996 Tour, Bjarne Riis, recently confessed that he won the race while on EPO and other performance enhancers.

In a strange twist there may be one more substance that officials will have to test for. New studies suggest that a dose of viagra will help more cyclists to climb that summit with more success.

The relationship between cycling and impotence has long been a dubious one. There is plenty of anecdotal and clinical evidence to suggest that cycling causes numbness and discomfort in the genital region, but whether or not that equates to long-term impotence is unknown. As there has been no qualified or scientifically acceptable studies carried out the jury's still out on the subject. However, the relationship between impotence and cycling has taken on a somewhat ironic twist.

Following reports that Viagra may improve breathing in low oxygen situations, it seems that cyclists may opt to take erectile dysfunction treatments regardless of whether or not they suffer from ED in order to improve their performance.

Erectile Dysfunction medications work by dilating blood vessels, and this effect might be the reason for the improvements in athlete’s performance in high altitude settings. By the same method that the drug improves circulation to the penis it can also pump blood through the lungs more efficiently.

Considering the world of professional cycling has been dogged by dope scandals, whether or not this will add a new dimension to drug testing is as yet unknown.