Double world champion Max Verstappen raised doubts on Thursday about his future in Formula One after his Red Bull contract runs out in 2028.

The 25-year-old Red Bull driver is leading Mexican team mate Sergio Perez in the championship after winning two of three races in 2023 and could clinch a third title with plenty to spare.

This weekend in Azerbaijan sees the first of six sprint races in the 23-round season, with the Saturday 100km dash now a standalone event with its own qualifying and unconnected to Sunday's main race.

Next year there will likely be a record 24 races, with China set to return after a four-year break due to COVID-19.

Verstappen is not a big fan of sprints and thought carefully when asked by reporters in Baku about the new format and expanding schedule.

"If we keep expanding the calendar and the whole weekend is that long, at one point you question yourself 'is it worth it?'," said the Dutch driver.

"I do like racing, I do like winning. I know that of course the salary and everything, you have a good life, but is it actually a good life?

"I think sometimes you get to a point in your career where maybe you want to do other stuff.

"I know that I have a contract until the end of 2028, and then we'll review again. But I do feel that if it's getting at one point too much, then it's time for a change."

Verstappen accepted it might seem odd to those on the outside, who just saw the wealth and the winning, but he was not interested in equalling or beating Michael Schumacher and Lewis Hamilton's record seven titles.

"I want to do other things, other competitions. A bit like Fernando (Alonso) did," he said.

Alonso, a double F1 world champion, is also a two-times winner of the 24 Hours of Le Mans and has taken part in the Indianapolis 500.

The Spaniard, now 41, is chasing his fourth successive podium with Aston Martin in Baku this weekend.