When I asked the world decathlon champion how he got involved in his sport, this is how he replied:

"I did loads of sports – tennis, rugby, swimming - all sports.

"I always got bored training.

"When I tried athletics, and each day we tried a different event, I was immediately hooked because it was never repetitive."

It was just an answer, delivered with patience and good grace, to a deeply unoriginal question from a total stranger.

But it struck me afterwards that it might contain a pointer to one possible route to salvation for the 25-year-old Frenchman's under-fire sport.

Long-form events, it is frequently argued, are deeply out of synch with the zeitgeist of our restless, channel-hopping age.

And, as far as athletics is concerned, nothing is more long-form than decathlon: a relentless two-day slog, apt to expose any chink in its exponents' armour, it is the Test cricket of track and field.

But an event for which, in training, it is legitimate, even beneficial, at least when young, to "channel-hop" almost at will from one discipline to another - that sounds like something much more likely to appeal to the youth of today with their dramatically attenuated attention-spans.

Even today, Mayer explains, he focuses on one event, then another in training because "the hardest thing in decathlons are the transitions".

That is not to suggest that athletics, and the decathlon itself, are above improvement.

One of many proposed innovations has been to stagger the start of the decathlon's climactic - and cruel - 1,500 metres.

In this way, as in the event's multi-sports cousin, the modern pentathlon, the first athlete across the line would be the overall winner - a big step forward in terms of making it accessible to a general audience, or so one would think.

Once again, Mayer, whom I am starting to like as well as admire, offers a candid and thoughtful take.

Asked if he is for or against such a change, he answers: "I was for, now I'm against.

"Because it would be impossible on a 400m track.

"It would mean that the leader would set off with such an advance that, by the time he had done a lap, the backmarkers still would not have started.

"And no-one would understand anything; as a race it would be hard to decipher.

"It appeared to be a good idea at first, but it is not like modern pentathlon because that is...much longer.

Even so: "We will find a solution I think in the next few years.

"The decathlon is hard to understand.

"I think that reduces spectators enormously.

"If someone really wants to understand the decathlon, they are truly interested in it.

“So we have a small public, but a very passionate public, I find."

Does he wish he were a sprinter, where most of the attention is?

"No, I don't care about having all eyes on me," he retorts.

Another aspect of the decathlon - and heptathlon - that it has always seemed to me the marketeers could make more of without becoming sappy is the spirit of comradeship between competitors. You find the same sort of thing in National Hunt horse racing.

Mayer has boiled this down to four words (five in his native French): Pain brings you closer.

"What sets the decathlon apart is that you spend two days together," he says.

"As the events succeed one another and you get tired, it is true you fight against yourself much more than the others.

"I would even say that we fight against ourselves with the others…

"The decathlon is, after all, quite a difficult and long-lasting discipline.

"In the waiting around and the pain, a lot of respect and friendship is created."

Talking of pain, Mayer also has a good word for that killer final event we have already touched on - decathlon's 1,500m finale.

It is, he says, "what makes us proud to finish".

It does not take long to register that this is a smart, as well as a gifted, man.

So I am a little surprised when he explains that he did not complete his university education.

"I did not have the time."

Couldn't you do both – train and study?

"There came a time when I couldn't, no.

"I got my baccalaureate.

"I began university, but couldn’t train at the same time. It was not possible.

"It was a choice: if it hadn’t worked, I would have taken up my studies again and it would have been no big deal.

"If I wanted to be Olympic champion or world champion, I had to do only athletics."

Easily bored then, but also ambitious and hugely determined.

Mayer finished second at the Rio 2016 Olympics, after which champion Ashton Eaton retired.

Did he feel more pressure this year in London, where he became world champion, knowing that people were already seeing him as Eaton’s heir apparent?

"Yes - as I had come second in Rio and the winner was no longer there, everyone was making me world champion before I actually was.

"There was a lot of pressure because for everyone it was a done deal, but for me it was not that at all."

He says he did not prepare any differently, however.

"It was just a question of knowing how to accept the extra pressure."

And now you have done it once, will it be easier next time?

"It will be simpler because…there is nothing higher than world champion, so I think the pressure cannot get any bigger.

"Now I know how to handle it, I think it will be easier."

As he says this, I wonder whether he ought not to consider consulting Cathy Freeman.

The two-time world champion 400m runner, a prior Olympic silver medallist, went on to be the golden girl of her home Olympics in Sydney 17 years ago - and then sank to the ground, trying to take it all in.

She later told me she was "swallowed up by the moment".

Seven years is an age in Mayer's gruelling, multi-faceted event, but if he can stay fit and avoid injury, something similar just might lie in store for him at Paris 2024.

I hope I can stay fit enough to watch him try.