I raced in the Streatham Common six-mile championship yesterday morning. After a little over 40 minutes and six up-and-down miles, it was over. I warmed down, trotting a further lap of the common. On my way home, I glanced at my watch: midday. Some 40 runners would be beginning the Sri Chinmoy Self Transcendence 24-hour race on the track at Tooting Bec now. I pitied them, then forgot all about them.

I showered, ate, wandered to Balham, went to Starbucks, went to Sainsbury’s, wandered home, ate, watched X Factor, slept for nine hours, watched the start of the Great North Run on TV and then ran to the track. As soon as I entered the gates, I remembered: the 24-hour race.

They had been going now for 22-and-a-half hours. There were about 35 left, some walking, some running. Among their number was a 78-year-old. It was a very low-key affair. A handful of people only were watching. You’d be forgiven for thinking that nothing out of the ordinary was going on. Tents had been erected around the perimeter of the track. A board displayed how far each competitor had gone. The two leaders had covered 130 miles. That is 130 miles around a 400-metre track. That is 520 laps. In the time it had taken the pair to run that distance, my life had been a blur of normality, despite me calling myself a ‘runner’. Compared to these people, I’m no runner.

I’d like to be able to use some flowery, descriptive language to describe their physical state, to write that they were bent double, that pain was etched across their drawn faces, that they were stumbling zombie-like around the track. But that wasn’t the case. They didn’t look fresh, but nor did they look like they had been running continuously for the previous 22-and-a-bit hours of their lives. The end was in touching distance though. A different sight may have greeted me at 2am or 5am. Of course, I was fast asleep.

I left with a group of others to run along the Thames, past a Craven Cottage preparing for the visit of Manchester City. As we climbed away from the river, returning to Tooting Bec, the watch of another runner pipped. ‘Midday,’ he said. The ultra-runners’ ordeal was over. They could finally stop.

The winner had completed an astonishing 141 miles. For me, that would be the product of two very good weeks of back-to-back training; he’d done it in a single day. And he hadn’t even gone anywhere. Such a distance on an A to B, I could just about conceive. But around a track? It seemed implausible. The 800 metres repetitions I do here on Tuesday nights can feel like purgatory.

I recognised one of the runners, a former training partner from my time in Peterborough. He had covered 122 miles, finishing 5th. His Achilles began hurting some six hours in. He carried on. He’s a doctor and tomorrow, he told me, he’d been in theatre. I asked him a few times, ‘why?’ – but he never seemed to offer a satisfactory response. What exactly inspires someone to run nonstop for 24 hours around a track? He joked that he’d never run again. Five minutes later he was snapping up a leaflet from the organiser of an ultra event in Crawley in April. Whatever possesses these people, whatever drives them on, these are the real heroes of our sport.