How Fast Can a Marathon Be Run?

Is there an absolute minimum time to run a marathon? Will humans ever break the 2 hour mark? What does it take to set a world record marathon time? 

Sabrina Stierwalt, PhD
5-minute read
Episode #259

marathon runners

The fastest marathon ever run on record was by Dennis Kimetto of Kenya in the 2014 Berlin marathon for a time of two hours, two minutes and 57 seconds. That means he ran an average pace of four minutes 41.4 seconds per mile over the entire 26.2-mile course. Kenyan runner Eliud Kipchoge and Ethiopian runner Guye Adola came very close to breaking this record at the Berlin marathon earlier this year.

While the fastest marathon time for men has been slowly but steadily improving for the last 30 years or so, the women’s record has held firm since 2003. Paula Radcliffe of Great Britain set the time to beat at two hours 15 minutes and 25 seconds (an average pace of five minutes 9.9 seconds per mile) in London over a decade ago.

Is there an absolute minimum time to run a marathon or will runners just keep getting faster? Will humans ever break the two hour mark? What does it take to set a world record marathon time? How does someone run a faster marathon?

What do you need to run a fast marathon?

There are three categories of conditions that must be met to get the fastest marathon time possible. A runner has to be strong, a runner has to be efficient, and the course conditions have to be ideal. Some of these conditions can be created or trained for while others are up to our genetics.

Strength: The strength or power behind a runner is usually measured by the rate at which oxygen flows through the runner’s body. How fast can the body deliver the oxygen it takes in to the muscles so that they can use it to produce energy? This rate, measured in milliliters of oxygen per kilogram of body mass per minute, is known as VO2 max. Your VO2 max depends on your age, your sex, and of course how much you train, but on average, healthy adult men have a VO2 max of 35-40 mL/kg/min while healthy adult women have an average VO2 max of 27-31 mL/kg/min. Elite runners, however, have rates of more than double those values at somewhere around 85 mL/kg/min for men and 77 mL/kg/min for women.

Studies have shown that including interval training (i.e. shorter bursts of activity followed by less intense periods like a mix of running and walking) can lead to more success in increasing VO2 max. However, there appears to be a ceiling on how high we can increase our VO2 max that depends on our genetics. For example, women on average tend to have lower levels of hemoglobin, a protein tasked with carrying oxygen in the blood, than men do which contributes to their marathon times being ~10% shorter. (They also tend to have higher percentages of body fat which likely sets a lower ceiling on VO2 max.) Doping drugs that artificially raise hemoglobin levels can help increase VO2 max but are illegal in marathon running.

Efficiency: Humans are at a disadvantage compared to, say, cheetahs when it comes to running because we run on two legs instead of four. Our center of mass thus sits directly over our feet and so with each stride, we waste energy that doesn’t serve to propel us forward. Some of it pushes back vertically and the rest is dissipated into the ground. Some of this issue of stride efficiency can be addressed with footwear. Shoe companies like Nike and Adidas are researching whether the use of springs or foam can make runners’ strides more efficient.

The ability of a runner to turn the energy of each stride into power, or their mechanical efficiency, is often referred to as “running economy.” While training can obviously help to improve your stride, the composition of our muscle fibers plays an important role in our efficiency and is up to our genetics. Fast-twitch muscle fibers, which rely on glucose over oxygen to make energy, are good for providing power for short bursts of movement like sprinting, while slow-twitch muscle fibers are better suited for continuous muscle contractions over longer periods of time, like running a marathon.  

Part of being an efficient runner is also having a strong heart to pump blood to the muscles. Runners typically need to be able to sustain a heart rate of around 160 beats per minute (or nearly 80% of their maximum heart rate) for the several hours it takes to run the race without building up too much lactic acid in the muscles.

Ideal Conditions: Even with the best equipment, the best genetics, and the best training, you will still need a cooperative course in order to break a marathon record. Most of the men’s records have been broken during the Berlin marathon and that is no coincidence as the route tends to be flatter than other courses. Most records are also broken in September and April when temperatures are more moderate and thus more optimal for running.


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About the Author

Sabrina Stierwalt, PhD

Dr Sabrina Stierwalt earned a Ph.D. in Astronomy & Astrophysics from Cornell University and is now a Professor of Physics at Occidental College.