Since the 1969 Olympic Games in Mexico City the topic of altitude and performance has received a lot of attention. Mexico City is situated at 2240m or 7314 feet. It was observed that winning performances in short events 100m, 200m, 4 x 100m and long jump were faster than world records at that time (1%). In contrast the distance running events 3000m steeple, 5000 and 10,000m were al much slower (4-6%). Since then, it has become clear that distance running performance (800m and up) is impaired at altitude. Studies have suggested that altitudes as low as 580-800m (1902-2624 ft)can already affect endurance performance [1,2].
A new study by Michael Hamlin from Lincoln University in Christchurch New Zealand and colleagues will soon be published that discusses an analysis of a large number of performances at various altitudes. An abstract of this study is already available on the website of the International Journal of Sports Physiology and Performance.
The authors analysed over 132,000 performances of athletes placed in the top 16 in at least one major international competition between 2000 and 2009. Almost 1900 athletes were included at 794 venues of varying altitudes. Professor Will Hopkins from AUT University in Auckland, New Zealand, one of the authors who has specialized in statistics and analysing such datasets, transformed the data so that events could be divided into 6 levels of altitude.
The results showed that there were marginal impairments in performance in distance events at altitudes as low as 150m (492 ft), but above 1000m (3280ft) performance decreases were as large as 2-4%.
In summary
Although it is known that altitude may impair endurance performance, this study suggests for the first time that already at very low altitudes distance running performance may be impaired. These impairments may be small and the higher the altitude the greater the impairment may be. There may not be any immediate practical takehome messages here, but the findings bring to light that when we are comparing endurance performances from different competitions objectively we have to account for altitude, even when the altitudes do not seem to be that extreme!
Evaluation of the study
Strength
- This study uses REAL data with real meaning and relevance
- analyzed a range of performance (we only discuss the enurance runnings events here)
Weakness
- Even though the sample size in this study seems large, one has to be aware that the analysis may have been influenced by the fact that important competitions were more likely to take place at lower altitudes (I did not check if this is indeed the case, but it does not seem an unreasonable assumption). If this is the case it is more likely that faster times are ran at races that are more targeted by athletes and where stronger competition may be present. If this is the case the performance effects reported may be slightly exaggerated but in general the message would still be the same.
References
1. Gore CJ at al Reduced performance of male and female athletes at 580 m altitude. Eur J Appl Physiol Occup Physiol. 1997;75(2):136-43.
2. Wehrlin JP, Hallén J. Linear decrease in .VO2max and performance with increasing altitude in endurance athletes. Eur J Appl Physiol. 2006 96(4):404-12.