England's preparations for their FIFA World Cup Round of 16 match against Mexico have sparked unusual discussions: players are permitted to use the blue pill, containing sildenafil, to combat high-altitude effects at Mexico City's Azteca Stadium, which sits 2,240 metres above sea level. FIFA and the World Anti-Doping Agency (WADA) do not prohibit the drug, originally developed for high blood pressure, as it may help athletes cope with reduced oxygen levels.
Altitude Challenge at Azteca Stadium
Mexico City's Azteca Stadium, at 2,240 metres (7,220 feet), presents a severe challenge due to lower oxygen levels. Fatigue, dizziness, and shortness of breath are common. England manager Thomas Tuchel acknowledged the difficulty after a 2-1 win over DR Congo, noting insufficient time for acclimatisation, as the team travelled directly from Kansas City. Mexico has kept four consecutive clean sheets and lost only twice in 89 matches at the Azteca.
Science Behind Sildenafil in Sports
Sildenafil, known for treating erectile dysfunction, was originally developed for hypertension. It widens blood vessels, potentially improving oxygen transport at altitude. A 2015 study showed performance improvements exceeding 35% above 3,800 metres, but benefits are minimal below 4,000 metres. Mexico City's elevation is below that threshold, so the drug may offer little advantage. In 2019, Argentine club Unión de Santa Fe considered sildenafil for matches in Ecuador.
Legal Status Under FIFA and WADA
The blue pill is entirely legal under current regulations. WADA's 2026 prohibited list excludes sildenafil, concluding it provides no significant advantage at sea level or normal conditions. FIFA imposes no restrictions. Despite the option, there is no indication England players intend to use it. The discussion highlights extreme measures teams consider for unique environmental pressures.
Match Context
England face Mexico in a high-stakes Round of 16 tie. Mexico, co-hosts, are confident after a 2-0 win over Ecuador. For England, overcoming altitude may be as tough as overcoming Mexico. In a previous match, England captain Harry Kane was denied a penalty against DR Congo but led a comeback victory.
