My invitation was rejected point-blank. He didn't want to watch. He wanted to compete in it. And he immediately got down to serious training.
Initially, he trained by running up and down the 12 stairs of his house, until the neighbours complained and the dogs over the road started barking.
Then, he moved his training camp from his home to a local multi-storey carpark, progressing on to the maintenance stairwell of a Thames River tunnel.
Vertical marathons do not have official Olympic recognition. But there is a growing worldwide circuit of organised runs up the staircases of some of the world's tallest and most famous buildings.
Ten events form an official World Vertical Circuit. London's Gherkin Tower, Milan's Pirelli Building, the Sofitel in Singapore, Taipei's 101 Tower, the Park Inn Hotel in Berlin, Basel's Messeturm, the 94-floor, 1504-step Sydney Tower and the Torre de Coliserole in Barcelona all host events.
Moscow, Vienna, Detroit, Toronto, Bangkok , Dubai, Auckland (Sky Tower) Kuala Lumpur and Munich have also held vertical marathons.
The world champion is 26-year-old Thomas Dold from Stuttgart, Germany. A former mountain runner, he has won the Empire State Run six times, completing his latest run in 10m 10s. The women's World Cup winner in 2010 was New Zealand's Melissa Moon.
At 101 floors and 2046 steps, the Taipei event is considered the toughest, but the Empire State Building race, organised by the New York Road Runners Club, is the most prestigious.
The Empire State Building was opened in May 1931 after taking one year and 45 days to build and was the world's tallest building.
It has 6500 windows, five entrances, 73 lifts, two banks, three coffee shops, 250 permanent staff and, every February, hundreds of upwardly mobile and perhaps mentally unbalanced athletes run up the 1576 steps to the observation deck.
Among those gathered in the lobby on 36th St and Fifth Ave for the start was my mate Martin. He wasn't aiming to break the record, just to avoid an infarction. The theme music for Chariots of Fire came into my head as I watched the athletes line up.
The professionals and elite runners with high cramp thresholds went first. Then a foghorn started the rest.
Vertical marathon is a full contact sport. No prisoners are taken. There was a lot of jostling and shoulder-barging as the runners pushed each other out of the way in a huge crush to get to the small-framed door to the staircase. Then it was stair-crazy all the way.
I talked to Martin afterwards. After I got the lift and arrived well before him.
The soundbite came after complaints of a stitch, oxygen deprivation and arthritis of the wrist: "I expected a nosebleed but I got sore hands from pulling myself around the staircase."
Remarkably, he finished 51st in a time of just over 14 minutes. That was 15 minutes quicker than the oldest man in the race.
Apart from a congratulatory cuddle from a King Kong lookalike, the only things our eldest son's godfather received for his exertions were a complimentary T-shirt, a sticky bun to replenish his blood-sugar levels, rehydration in a half-full wobbly paper cup and a ride down to ground level in one of the Empire State's elevators. After queueing.
Martin says he now views New York in an entirely different light. The view from the top of the Empire State Building took his breath away. As well as most of his stomach contents.
CHECKLIST
Further information: The Empire State Vertical Marathon is held each February. For more about the vertical running circuit, see verticalrunning.org.
Kevin Pilley watched his friend run up the Empire State Building at his own expense.
