In 2022, Aleksandr Sorokin ran 198.6 miles in 24 hours, nearly eight marathons in a single day — a new world record.
How does anyone run that far, that fast, for that long? It turns out six factors have to be perfectly dialed in to break a distance-running world record: VO₂ max, form, footwear, fuel, environment, and the mind.
To understand each one, Business Insider met with athletes and scientists who are pushing the limits of human endurance. We tracked down Kristian Blummenfelt, the Olympic and Ironman champion whose team recorded a VO₂ max of 101.1.
We visited Stanford's biomechanics lab, where researchers built a digital model of Dean Karnazes, who holds the record for the longest distance ever run nonstop.
We tried on supershoes and looked at how much energy their foam gives back. We explored what an ultrarunner's gut can handle, and what a hot room does to the body's core temperature.
Then there's the mind. We went to Queens, New York, for the Sri Chinmoy 3100, a race where runners circle the same block for 52 days, and asked the front-runner what keeps him going.
Watch the full video to find out what it takes.