Max Verstappen has said medical checks show the lower part of his spine is in poor shape. On Thursday, he flagged the bumps at tracks such as this weekend's COTA at the US GP as a real long-term concern.

Looking ahead to the weekend in Austin, the Red Bull driver had initially joked about the Texas surface. Speaking after his victory in Singapore, Verstappen said COTA could leave him needing "a new spine" after noticing just how uneven the track surface appeared during a recent WEC race.

During media day ahead of the United States Grand Prix, however, Verstappen made clear that "it's not really a joke," and later revealed the extent of the damage on his spine that he believes has come as a consequence of the physical forces endured by drivers when their F1 cars hit bumps on a track.

Verstappen: 'It's not really a joke'

Photo: Race Pictures

Speaking on Thursday, Verstappen admitted his earlier remarks had been made light-heartedly, but in reality, the situation regarding F1's bumpy circuits are "getting a bit out of control."

"I was joking about that in the last race, but it's not really a joke to be honest," Verstappen said. "We mentioned this already for years, that it's actually getting a bit out of control. And I'm sure that tomorrow it's going to be quite tough to find the right compromises around this track in places where it's just extremely bumpy. I don't know how our car is gonna respond to that."

Focusing more closely on COTA, Verstappen added: "I love this track, I love this place. It's one of the best layouts ever and it's one of the best venues, best city to be at. But for me the bumps are unacceptable. Over time they've been grinding a little bit here and there but it's just putting a plaster on the big problem.

"But that of course means you need to really fully open up the track. That costs a lot of money and time but that's the only way to get rid of it because these bumps are not natural and they are out of control."

Verstappen reveals spine damage from bumpy F1 tracks

The four-time world champion also addressed the fact the circuit is built on former marshland - meaning organisers face difficulties keeping it in good condition. It is an "excuse," however, that the Dutchman is not buying.

"You can use the excuse that the soil is the problem but then you should have known that and you need to make sure that you reinforce it more," Verstappen said.

He then revealed the physical toll he has incurred as a result of F1's bumpy circuits, with the 29-year-old adding that his health concerns have increased the older he gets.

"Last year, for example, you pull around 5-6G in a corner, but I had some impacts, vertical load, which was over 9G on my spine, which I can tell you is really not fun, and especially the older you get, you think about that more and more."

"So I know that's part of racing, I know that can be part of sport, but it's of course also further damage from the cars that we had the last few years. And now if we continue with finding this acceptable to drive on, then you are going to suffer with that much more."

"People can say there are worse sports out there for damage to parts of your body. For sure, but that's why I'm not doing them. So yeah, it's not nice."