Does altitude give any advantage to the 800 meter runners? This simple question does not have a simple answer. To balance the pros and cons let's look at the arguments and at the statistical evidence before reaching a tentative conclusion.

Generally, marks run at a venue located above 1000 m are considered "altitude" marks, indicated by the addition of an "A" to the mark. Just as the 2.0 m/s wind limit the altitude limit is somewhat arbitrary. It is set at such a value that most sites are below the limit. But of course any advantage not simply just starts exactly at this limit, nor does it remain constant at still higher altitudes. Just as with wind assistance, where the advantage is dependent on the exact wind, altitude advantage is bound to vary with the exact height, or rather with local atmospheric pressure. This of course means that to make the statistics as pure as possible we would have to add the local barometer reading to every mark. This is hardly practical. So statisticians use the "A" mark to indicate "serious" altitude advantage. Unlike wind advantage though, this does not disqualify a mark for any records. The IAAF does take altitude marks into consideration for national or even world records.

At high altitudes atmospheric pressure is generally lower. Therefore the athletes experience significantly less air resistance, which enables them to run faster. Since air resistance increases with the square of the velocity, the advantage is obviously more important for sprinters. Many sprinters have set their personal bests at high altitude venues. Other disciplines that might benefit from high altitudes are the long jump and the triple jump. This explains in part why Bob Beamon's famous long jump world record of 8.90, set at the 1968 Olympics in Mexico City, stood for more than 20 years.

At lower speeds the athletes gain less advantage from lower atmospheric pressure, so long distance runners should not benefit as much. But lower air pressure also means less oxygen, and this is a serious disadvantage.

Muscles contain reserves which can be used for short bursts of activity. This is called the anaerobic system. When more energy is needed oxygen is required to burn further reserves. This is called the aerobic system. Generally human beings can rely on their anaerobic system for approximately 30-40 seconds. After that the aerobic system has to take over. This makes the 400 m a predominantly anaerobic affair, and all distances beyond 1500 m are considered aerobic. It is generally thought that performances at 1500 m and beyond suffer from the lack of sufficient oxygen.

The 800 meter is roughly 50% anaerobic, 50% aerobic. So the question whether the advantages of lower air resistance outweigh the effects of lack of oxygen does not have an obvious answer. But we can take a look at the statistics to see whether they show any performances that would indicate any advantage.

Yes there would be. Unfortunately statistics on longer distances are not as straightforward as they are for shorter distances. Distances up to 400 meter are run in lanes. Unless we are dealing with heats we expect athletes to simply run as fast as they can. But at the 800 meter only the first 100 meters are run in lanes. After that tactics play an important role to the outcome of a race. For instance the Olympic final in Sydney was a tactical race, and it produced such a slow winning time it was not even among the 75 best marks of the year. On the other hand races at Grand Prix meets such as Zürich or Brussels often have pacemakers, which will usually result in fast races.

The most famous "altitude" venues are probably: Mexico City, Nairobi, Johannesburg, Sestriere and College Station (USA). The organisers of meets at the latter two venues apparently feel that 800 meter runners do not benefit from altitude: they never schedule any distances beyond 400 meter. However the other three venues have seen fast 800 meter races. If there is an important advantage to be gained we should expect at least some athletes to have set marks near their personal bests.

In 1968 the Olympic final at Mexico City was won by Ralph Doubell in 1:44.3 (manually timed). This at the time equalled the world record. Years later the performance was "corrected" by electronic reviewing to 1:44.40. So we could see this as some evidence there is an advantage. On the other hand in those years there were rather few races in which the top athletes met each other, and pacemakers had yet to be invented. So unless the race was tactical the Olympic final was almost bound to yield one of the fastest times of the year. In fact there have been many world record races at the Olympic 800 meters: three of them in the early days (1908, 1912 and 1932), another one in 1976, when Cuban Alberto Juantorena produced a winning 1:43.50. And recently when David Rudisha set his amazing world record in London 2012. Doubell's race was fast, but it was nowhere near some other extreme results at the same games, such as Bob Beamon's long jump record, or the 400 m world record which stood for 20 years. So the evidence is hardly compelling.

There are just three marks set in Johannesburg below 1:45. As early as 1973 Fiasconaro produced a 1:44.7, which still stands as its track record. Late 1999 the World Cup race was won by Kimutai in 1:44.91. In 2001 Sepeng showed early form by winning in 1:44.95. None of these is even close to the athletes personal best marks. We may argue that Kimutai was tired at the end of the 1999 season, or that Sepeng had hardly started his season in 2001. But the fact remains that none of these marks is amazingly fast.

The famous capital of Kenya has probably seen more long distance races at altitude than all other venues together. There have been many marks below 1:45 at Nairobi, which is hardly surprising given the wealth of Kenyan middle distance runners. For a long time the track record was only a moderate 1:43.71, set in 2003 by Japheth Kimutai. In 2011 the incomparable David Rudisha, in world record shape, vastly improved this time to 1:42.84. In 2012 he ran even faster, clocking 1:42.12. But as of 2013 those two marks of Rudisha are the only ones below Kimutai's old record. Only eight times in total has anyone run inside 1:44 at Nairobi.
Now we may argue that the track in Nairobi is possibly not of the quality we encounter at modern Olympic or Diamond League venues. Marks in Nairobi are frequently given as manual times, which suggests facilities could probably be improved. Also most big races in Nairobi are Championship qualifications which would not have a pacemaker. Then again many Kenyans start very fast, so their races usually do not need any pacemakers. And the fact remains that the marks, if anything, are not really spectacular. Athletes such as Kimutai, Kiprotich, Kiptoo or Bungei have all run much faster in Europe. The track record by Rudisha is a terrific mark, but Rudisha has ran faster nine times already, in several cases by more than a second.

It remains to be seen what will happen if the track in Nairobi ever gets fully modernized. Perhaps the world will be amazed by a rush of stunning 800 m records. But the current figures just say this: the track record at Nairobi is the fastest 800 m mark ever run at altitude, and it currently (after the 2011 season) only ranks as the 56^th mark on the all time list!