In an out-of-this-world feat, British astronaut Tim Peake competed in his own version of the London Marathon on Sunday.

Peake completed 26.2 miles strapped into a harness attached to a treadmill aboard the International Space Station in 3:35:21. In 1999, he completed the distance on the ground in 3:18:50.

The 44-year-old astronaut's conditions were much different than the approximately 42,000 runners who ran in London.

Because there was no gravity, that means the treadmill can't have an incline. But it also meant he had a harness attached to the treadmill to feel his own weight. His trainer Patrick Jaekel said the weight on his shoulders was like running with an object of 22 to 44 pounds.

Also, there are no cooling breezes. But he had fans to help keep him warm and evaporate some sweat that can't drop down without gravity.

Peake was able to see the course and hear the crowd cheer via the RunnSocial app. The speed of the treadmill matched the speed at which he saw the course ahead, according to Jaekel.

Fellow crew members were available to give him food, water and a fresh shirt.

NASA astronaut Sunita Williams completed the Boston Marathon from space in under 4-1/2 hours in 2007.

Peake has been aboard the space station since December.

"I have certainly been putting in time on the T2 treadmill," Peake told the BBC during a broadcast from space. "I've done a few half marathons and a little longer distance as well ... I'm sure there will be a few points where I wish I had done a bit more training."

A recorded message in which Peake wished the competitors luck was played on big screens before the runners set off in London.

Kenyan long-distance runner Eliud Kipchoge won the men's race in a course-record two hours, three minutes and four seconds to triumph at the event for the second year in a row. His time was the second fastest of all time, only seven seconds outside the world best at the 2014 Berlin Marathon by fellow Kenyan Dennis Kimetto.

.@astro_timpeake's estimated #LondonMarathon times on the #Principia #blog: https://t.co/jSTMSw82Nq pic.twitter.com/WiJCbfZu4H— ESA Operations (@esaoperations) April 24, 2016