PARIS (AFP) - Statistics have now confirmed anecdote as fact: South American teams used to playing at high altitude have a major advantage over lowland opponents, according to a study published on Friday by the British Medical Journal (BMJ).
Oxford University researcher Patrick McSharry trawled through the scores of 1,460 international matches played at different altitudes in 10 countries in South America spanning more than a century.
The lowland countries were Brazil, Argentina, Uruguay and Paraguay, all of whose national stadia are at height of 60 metres (195 feet) or less, followed by Peru (90 metres, 292 feet) and Chile, whose stadium is at 520 metres (1,690 feet).
The four highland nations were Venezuela (1,000 metres, 3,250 feet), Colombia (2,600 metres, 8450 feet), Ecuador (2,800 metres, 9100 feet) and Bolivia (3,700 metres. 12,025 feet).
Altitude difference had a major impact on performance, McSharry found.
Teams that were used to playing at altitude scored more and conceded fewer goals as the height progressively increased.
Each additional 1,000 metres (3,250 feet) increased the goal difference by half a goal.
McSharry found that in the case of two teams from the same altitude, the probability of the home side winning averages 53 percent.
But this rose to an astonishing 82 percent for an altitude difference of 3,695 metres (12,008 feet), such as when Bolivia played sea-level opponent Brazil.
But it fell to just 21 percent when the altitude difference was minus 3,695 metres (minus 12,000 feet), i.e. when Brazil played at home to Bolivia.
High altitude is known to cause lack of oxygen, cold and dehydration, leading to breathlessness, nausea, dizziness and fatigue, and strenuous sport such as football can make the symptoms worse.
Coaches can help their side by factoring in a player's individual susceptibility to altitude sickness when making their selection, says McSharry.
World football governing body FIFA on Saturday relaxed their previous ban on international matches at altitude to 2,750 metres (9,022 feet) "without acclimatisation" a move that still blows the final whistle for games at La Paz in Bolivia and in the Ecuadorean capital Quito.
In May, FIFA originally slapped an unconditional ban on matches at 2,500 metres (8,125 feet) or higher after its medical committee advised that playing at such a height was neither healthy nor fair.
It also cited home-field advantage of high-altitude teams over visiting teams from lower altitudes.
|CONCACAF Champions League Review: Giovinco inspires Toronto, Tigres held|
|Ranieri: I´ll quit Nantes if offered Italy job|
|Barcelona are great even without Neymar – Willian|
|Conte wants to see out Chelsea contract but has bags packed|
|Messi goal will give Barcelona more space at Camp Nou – Suarez|
|Conte defends ´incredible´ Christensen after Barcelona error|
|Bayern taking nothing for granted after 5-0 demolition – Heynckes|
|Valverde: Barcelona away goal not definitive for progression|
|Muller & Robben bemoan poor first half despite Bayern rout|
|Chelsea close to a perfect game against Barcelona - Conte|
|Defending for 90 minutes at Barcelona a ´suicide mission´ - Fabregas|
|Championship Review: Villa miss chance to move into promotion places|
|Messi ends his Chelsea hoodoo|
|Chelsea 1 Barcelona 1: Messi breaks Blues hoodoo to leave tie in the balance|
|Bayern Munich 5 Besiktas 0: Two-goal Muller inspires emphatic win after Vida red|
|De Vrij confirms intention to leave Lazio on free transfer|
|Sanchez move down to Champions League frustration at Arsenal - Mourinho|
|Mourinho suggests Pogba is fit to face Sevilla|
|AFC Champions League Review: Hulk & Oscar lead Shanghai, Jeonbuk Motors hit six|
|Cech expects Ospina to start for Arsenal in EFL Cup final|
|Gueye signs new Everton deal until 2022|
|FA charges Man City and Wigan for failing to control players|
|Aguero faces no action over Wigan fan incident|
|Las Palmas get green light to sign Viera replacement amid Nasri talk|
|FA issues West Ham with anti-doping charge|
|Florenzi a doubt to face Shakhtar, confirms Roma´s Di Francesco|
|Maybe we ´lock him up or tie him up´ – Montella ponders how to stop Sanchez|
|Pogba and Ibrahimovic train with Man Utd ahead of Sevilla tie|
|Zidane hints at resting Ronaldo for Real Madrid´s trip to Leganes|
|Modric adds to Real Madrid injury worries|
|Wolfsburg turn to Labbadia in fight for Bundesliga survival|
|Wigan to investigate pitch invasion after win over Manchester City|
|Drogba ´couldn´t be more proud´ as son signs for Guingamp|
|Stones making no excuses for shock Wigan defeat|
|Bellugi scathing of Inter form and transfer policy|
|Rakitic: I´ve not seen Messi in the gym this often|
|Besiktas face Bayern test, Messi seeks to end drought - Champions League in Opta numbers|
|Sevilla v Manchester United: Montella and Mourinho unified in pursuit of identity|
|Jose Morais: The Mourinho acolyte bringing Barcelona to Barnsley|
|Rakitic: More to Chelsea than just Hazard|
|Klopp tactics behind my form – Salah|
|Young: Man United can win Champions League|
|Messi is best but ´not invincible´, says Pedro|
|It´s a red card – Guardiola accepts Delph sending off amid City´s Wigan woe|
|Aguero lashes out at fan as tempers flare after Wigan stun Man City|
|Grigg revels in dousing Manchester City´s fire|
|Wigan Athletic 1 Manchester City 0: Grigg ends Guardiola´s quadruple dream|
|Messi the best but don´t forget Suarez, says Chelsea boss Conte|
|I need a great game – Hazard aiming for Messi heights|
|AFC Champions League Review: El-Arabi´s brace seals Al Wahda´s fate|
|Barcelona boss Valverde tells Chelsea: History counts|
|Schmidt departs as Wolfsburg face relegation fight|
|Madrid, Barca & PSG are Champions League favourites, says Heynckes|
|Former football coach Bennell sentenced to 31 years|
|Hummels wary of ´top European team´ as Bayern prepare for Besiktas|
|WATCH: ´Crazy´ Evra drives to West Ham training in London cab|
|Barca clash a chance for Chelsea ´to do things right´, proclaims Rudiger|
|Lucas claims Tottenham can win Champions League|
|Barcelona tie will not decide Conte´s Chelsea future, says Deco|
|Lewandowski won´t be distracted by Real Madrid rumours|
|Man Utd must not underestimate Sevilla - Navas|
|Iniesta will not be made welcome at Stamford Bridge, warns Azpilicueta|
|Ballack sees ´a big difference´ between Bundesliga and Premier League|
|Betis boss would have preferred to face Madrid´s BBC|
|Chelsea v Barcelona: Messi´s blues against the Blues|
|James leaving Madrid was the best thing, says father|
|He´s looking good – Zidane thrilled with Ronaldo|
|It needs to take 30 seconds – Matic wants quicker VAR|
|Gattuso: My job is to be the players´ nightmare until season´s end|
|I wasn´t good enough – Guardiola reveals Wigan rejection|
|Brazilian derby between Vitoria and Bahia abandoned after red-card frenzy|
|It was crazy, but I like that - Zidane revels in eight-goal Betis thriller|