How Fast Can a Marathon Be Run?

October 31, 2017

5-minute read

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?

259 – How Fast Can a Marathon Be Run?

Your browser doesn’t support HTML5 audio

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.

Is there a minimum time needed to run a marathon?

So will humans ever be able to do better than a two-hour marathon? Statistical models, like those developed by Dr. Mark Denny and published in the Journal of Experimental Biology, suggest that, although the precise limits may not be clear, those limits exist. In other words, there are maximum running speeds for racing species including greyhounds, thoroughbred horses, and elite human athletes.

Dr. Michael Joyner, a professor of anesthesiology at the Mayo Clinic, and his colleagues Drs. Alejandro Lucia and Jonatan Ruiz, developed a model of marathon performance to answer the question of whether or not there is a minimum time needed to run a marathon. When all parameters like runner strength, runner efficiency, and course conditions are set to their optimal values, their model predicts the fastest time to be one hour 57 minutes and 58 seconds. Joyner and his colleagues predict that the two-hour lower limit will be broken relatively soon sometime between 2025 – 2030 and by a runner of small stature that has been exposed to high altitudes and significant physical activity since childhood.

This last prediction raises an interesting question—do you have to be East African to set a world marathon record? Recent records sure do seem to suggest it! All top 10 current marathon record holders are East African, hailing from either Kenya or Ethiopia. However, historically, Eastern Europeans, Australians, and New Zealanders have also had extended periods of success in setting long distance running records. The key appears to be a combination of nature versus nurture.

A small stature helps runners to be more efficient and so does having lived extensively at high altitudes. With less available oxygen in the air at high altitudes, the body will compensate by increasing its red blood cell count which in turn can increase your VO2 max. Another key to raising your personal VO2 max ceiling is having been consistently physically active as a kid. Of course, the most important ingredient for a winning race that all current record holders have in common is training really, really hard.

How can I improve my marathon time?

Elite runners tend to have “best” marathon times that are 4.6 to 4.7 times their fastest 10k race times. So if you have a 10k race time, you can get a rough estimate of what to expect from yourself in a marathon, given the proper training of course. Once you’ve done what you can to improve your strength and your efficiency within the allowance of your genetics, your best bet to improving your time is then to pick a flat course on a cool day. If you can arrange for a tailwind, that might help too.

Of course, motivation can also help. Some experts suggest that after marathon record times were somewhat stagnant in the ‘70s and ‘80s, they began to improve again once larger sums of prize money were offered. So if the physical activity alone is not enticing enough, pick a race that also rewards you with money or perhaps a little fame.

Until next time, this is Sabrina Stierwalt with Ask Science’s Quick and Dirty Tips for helping you make sense of science. You can become a fan of Ask Science on Facebook or follow me on Twitter, where I’m @QDTeinstein. If you have a question that you’d like to see on a future episode, send me an email at everydayeinstein@quickanddirtytips.comcreate new email.

Image courtesy of shutterstock.