title: Effect of altitude on physiological performance: a statistical analysis using results of international football games.
abstract: OBJECTIVE
  To assess the effect of altitude on match results and physiological performance of a large and diverse population of professional athletes.
  
  
  METHODS
  Statistical analysis of international football (soccer) scores and results.
  
  
  METHODS
  FIFA extensive database of 1460 football matches in 10 countries spanning over 100 years.
  
  
  RESULTS
  Altitude had a significant (P<0.001) negative impact on physiological performance as revealed through the overall underperformance of low altitude teams when playing against high altitude teams in South America. High altitude teams score more and concede fewer goals with increasing altitude difference. Each additional 1000 m of altitude difference increases the goal difference by about half of a goal. The probability of the home team winning for two teams from the same altitude is 0.537, whereas this rises to 0.825 for a home team with an altitude difference of 3695 m (such as Bolivia v Brazil) and falls to 0.213 when the altitude difference is -3695 m (such as Brazil v Bolivia).
  
  
  CONCLUSIONS
  Altitude provides a significant advantage for high altitude teams when playing international football games at both low and high altitudes. Lowland teams are unable to acclimatise to high altitude, reducing physiological performance. As physiological performance does not protect against the effect of altitude, better predictors of individual susceptibility to altitude illness would facilitate team selection.
authors.affiliation: Systems Analysis, Modelling, and Prediction Group, Department of Engineering Science, University of Oxford, Oxford OX1 3PJ. patrick@mcsharry.net
authors.forename: Patrick E
authors.initials: PE
authors.lastname: McSharry
mesh_terms: D000531:Altitude; D054874:Athletic Performance / Q000502:physiology*; D006801:Humans; D012916:Soccer / Q000502:physiology / Q000706:statistics & numerical data*; D013020:South America