After the most dramatic offseason in recent Formula 1 history comes its longest ever season.

The season-opening Bahrain Grand Prix will be the first of 24 race weekends. Champion Max Verstappen — sixth in the first practice Thursday — is among several drivers raising concerns about the impact of a relentless schedule.

As practice got underway, the focus remained on Red Bull and team principal Christian Horner. He remains in charge after the team's parent company in Austria said a grievance made against him was dismissed after an internal investigation, but the matter continued to dog Horner Thursday after alleged evidence was made public via anonymous email.

Also this offseason, seven-time champion Lewis Hamilton stunned the series by announcing he is moving to Ferrari next year. The switch surprised his current team, Mercedes, and even his parents. Also, Netflix star Guenther Steiner was removed from his role leading the Haas team.

It's been a lot for drivers and F1 fans to follow even before a marathon season begins.

All three past and present champions on the grid — Hamilton, Verstappen and Fernando Alonso — agree 24 races push the limits of what F1 drivers and team members can take.

“When I started we had 16 races,” said two-time champion Alonso, who has a record 377 career race starts. “Now we are up to 24 and this is not sustainable for the future for anyone.”

“I feel already that we are way over the limit of races," said Verstappen, who questioned if some drivers might “start shortening their careers” over the workload.

Since Liberty Media took over F1 before the 2017 season, the number of races has risen from 20. The growth is driven by Liberty's strategy of staging races in destination cities like Las Vegas, Miami, Jeddah in Saudi Arabia and, from 2026, Madrid.

Verstappen's Red Bull teammate, Sergio Perez, voiced concern for staff on F1 teams who, he said, seemed exhausted at the final races last year.

“I remember seeing a lot of zombies in Abu Dhabi, after Vegas,” he said. “We are trying to basically put some points across that it’s not only for the drivers, to be honest. There’s a lot of mechanics, engineers and basically they travel the world weekend after weekend, a lot of hours on the planes."

This longer season means an extended goodbye for Hamilton, who is leaving Mercedes at the end to join Ferrari, and raised concerns over how the expanded calendar might worsen F1's impact on the environment.

RACE PREP

Daniel Ricciardo was a surprise leader in the first practice for Red Bull's second team, the newly renamed RB, formerly known as AlphaTauri. The two McLarens of Lando Norris and Oscar Piastri were second and third fastest.

Hamilton set the fastest time in the second session, run under lights in conditions more similar to qualifying and race day on Saturday.

“The car was feeling good, but we can't get ahead of ourselves,” the seven-time champion said. Mercedes teammate George Russell was second-fastest and Alonso third for Aston Martin.

Red Bull lagged behind as Verstappen was sixth fastest in each session and Perez was 12th in the first session and 10th in the second.

TRACK SAFETY

Testing was twice disrupted by drain covers flying off and leaving debris across the track — prompting Verstappen to voice concerns over safety — but that problem has been solved for now. Rain isn't a major concern in Bahrain so problem drains at two corners have simply been filled in with concrete.

Modern F1 cars' powerful ground-effect aerodynamics generate grip between the floor and the track surface but that force can also pull loose items away from the ground. Carlos Sainz Jr.’s Ferrari was badly damaged by a water valve cover in practice for the Las Vegas GP in November, underlining the risks to drivers.