The science behind the world’s greatest race

Born to run: The average marathon runner takes 50,000 steps during the race. © Getty

Should you run a marathon? Yesterday, the incredible Eliud Kipchoge set a new record at the London Marathon. Around 40,000 people joined him in the gruelling 26.2 mile race around the city.

Yesterday Eliud Kipchoge smashed the London Marathon’s record for the fastest finish time. He completed the race in 2:02:37 — the second-fastest marathon ever recorded. (He also holds the world record, 2:01:39, achieved last September in Berlin.)

He and the 40,000 runners behind him must now spend a few days letting their bodies recover. Marathons are hard work, and they do strange things to the body.

For starters, the average runner finishes the race about 1.25cm shorter than when they started. Luckily, they stretch out again after 24 hours or so.

Meanwhile, runners can lose up to six litres of sweat. The body’s core temperature reaches a fever pitch of around 39C, then plummets once the race is over. The sudden drop in temperature puts people at risk of hypothermia, which is why they are often wrapped in foil blankets.

Inside, your body’s support systems go into overdrive. The heart pumps four times the usual amount of blood, mostly to the brain and muscles. This means that other organs, such as the kidneys, stop working.

After around 20 miles, the body has burned up most of its energy. This is when runners hit “the wall”: the feeling that they cannot continue. It is sheer determination that forces them on.

Yet despite the toll it takes on the body, marathons are extremely popular.

Run for it?

Why put yourself through all that? Marathons seem to be specifically designed to put your body through hell. In rare cases, they can even be deadly. Exercise may be good for you, but marathons are definitely not.

But for the converted, that is not the point. Marathons are a test of endurance. Humans were born to run. They may not be the fastest animal on the planet, but they can run farthest and longest. Marathons are a testament to that ancient skill.

You Decide

  1. Would you like to run a marathon one day?


  1. Create a poster which gives tips for staying healthy while running a marathon.

Some People Say...

“I run in a void. Or maybe I should put it the other way: I run in order to acquire a void.”

Haruki Murakami

What do you think?

Q & A

What do we know?
Marathons are 26.2 miles as a nod to Ancient Greece. The distance is based on a legendary run by the soldier Pheidippides in 490 BC. He ran from the town of Marathon to Athens in order to announce a victory in battle, a distance of about 25 miles.
What do we not know?
Whether we will ever see a two-hour marathon. Many have tried, but the barrier remains stubbornly unbroken.

Word Watch

Six litres
According to the Boston Athletic Association, the average person sweats 0.8 to 1.4 litres per hour of exercise. This equates to between 3.4 to six litres during a marathon.
When your body temperature drops below 35C. According to the NHS, early symptoms include shivering, cold skin, slurred speech and confusion. Normal body temperature is around 37C.
Four times
According to Professor Niall Moyna of Dublin City University, writing for RTÉ.