Why are Marathons almost exactly two hours?
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Why are Marathons almost exactly two hours?<br>Chasing an explanation that doesn't exist, featuring pendulums, urbanisation, physiology and Attic geography
Oliver<br>May 23, 2026
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I recently learned that the acceleration due to gravity on Earth (9.81m/s^2) being very close to π^2 (9.87) is not actually a coincidence, due to the definition of a metre being somewhat derived from the swing of a pendulum.
After seeing that the 2-hour marathon mark was finally broken by Sabastian Sawe and Yomif Kejelcha, I wondered if there was a similarly interesting reason that the record for a marathon was so close to exactly 2 hours. I was unable to find a good explanation of the two hour mark online so decided to go on a CGP Grey-inspired wild goose chase.
Sabastian Sawe breaking the record<br>Overall, it turns out it is indeed just a coincidence, but I thought it would be interesting to try to find any possible connection at all and share what I learnt.<br>Why did we decide to run 42.195 kilometres, and why are the records for this almost exactly 2 hours? There are probably two main avenues that the distance and the 2 hour time could be connected:<br>the specific history of the marathon has some relation to the 2 hour time; or
humans like running a distance that, when run optimally, corresponds to about 2 hours.
The history theory
You have probably heard the origin story of the marathon: a Greek messenger, Pheidippides, ran from the town of Marathon to Athens to pass on a message relating to the Persian invasion, was able to give his message, then immediately died from exhaustion.<br>This may not be true - Herodotus (sometimes labelled the ‘father of history’) writes that the messenger actually ran all the way from Athens to Sparta for help, which would be at least 240 kilometres.<br>Why were the Persians at Marathon at all? In 490 BC, as Sparta was incapacitated by internal turmoil, the Persians wanted to punish Athens and Eretria for their actions in a previous war. After a successful island campaign, the Persians laid siege to Eretria. After a week of the siege, some Eretrians betrayed the city and opened the gates to the Persians, and the city was destroyed. The Persians then wanted to sail on to Athens, and as you may be able to see on the maps below, the bay near Marathon made sense as a convenient landing spot.
The Brown Line shows the path of the Persian Invasion of 490 BC<br>However, the Athenians beat the Persians at the Battle of Marathon after the landing. The Persians then decided to sail on to Athens to attack the unprotected city while the Athenian army was still at Marathon. This is where the messenger comes in in some versions of the story - it was important that the Athenians knew their army had won, as otherwise they may have surrendered to the Persians.<br>As it happened, Marathon was about 40 kilometres from Athens. When the marathon was reinvented as the modern race, the first few races were indeed run from Marathon to Athens. In the 1896 Olympics, the race was about 40 kilometres, and the winning time was 2:58:50.
So, there being a decent landing spot approximately 40 kilometres from Athens does indeed seem like a coincidence unrelated to the race being 2 hours.<br>But I think there’s still an angle to explore here - why was Marathon in Athenian territory but Eretria wasn’t? Perhaps there is some travel time-based reason behind this. As an example, throughout human history, the maximum commute time which humans would generally accept to get to work was about half an hour each way. This is known as Marchetti’s Constant, and approximately held true over most of the time humans have lived in cities.
Radii around a city centre that can be traversed in 30 minutes with different forms of transport<br>There may be similar restrictions on the limits of the authority of city-states like Athens. After a certain travel time, it is unlikely that a city (as opposed to a more structured empire such as Persia) would be able to, or want to, militarily enforce its authority over nearby areas. Maybe there’s a similar distance at which a sort of urban gravity kicks in, such that no town that was as close to Athens as Marathon was could ever hope to develop to the size of Athens, because people would just go to Athens. Maybe this travel-time distance is something in the order of 8 hours (being the hours worked in a day?) - which would come to about 40/50 km at a certain walking pace. And maybe 8 hours of walking corresponds to 2 hours of running perfectly. Maybe.
Peak Athenian Territory in red<br>Overall, does this work? No.<br>It’s all far too hand-wavey and probably just pseudoscience.<br>Historically, it appears it was only an accident that the marathon came out to anywhere near 2 hours. Furthermore this theory goes nowhere to explaining why the records have been almost exactly 2 hours.<br>This is because the modern marathon distance of 42.195 km was...