Adrian Newey has revealed he was battling health issues during his first year at Aston Martin, leading to a "difficult period" as the team also struggled to adapt to Formula 1's 2026 regulations.
Newey, who holds the joint role of team principal and managing technical partner, left Red Bull in 2024 and joined Aston Martin in March 2025.
The timing of Newey's arrival was among a number of factors that meant the Silverstone-based team delayed the early development of its 2026 car last year, which contributed to it being woefully underprepared for the start of the season in March this year.
Fernando Alonso scored the team's only point of the season during a chaotic race in Monaco, but with no upgrades due until the Hungarian Grand Prix in late July, the team has been firmly planted at the back of the grid.
Newey attended the opening round of the 2026 season in Australia, but opted against travelling to the next four rounds in China, Japan, Miami and Canada.
An article on Aston Martin's website said "a brief spell of illness" was in part responsible for his absence, although Newey confirmed he has now recovered from the unspecified health issues.
"I'm OK now, but it's been a difficult period," he said. "In truth, I was not 100 per cent last year. I had to balance health and work much more carefully.
"The team handled it incredibly well. I kept a very good relationship with the engineers and I don't feel it caused too much of a blip. That's a testament to how adaptable and supportive everyone here is."
The start of the 2026 season has exposed shortcomings for Aston Martin on both the chassis side and with Honda's power unit in the back of the car.
Vibrations stemming from the Honda engine meant the team was unable to complete the mileage it needed in preseason testing and continued to plague the car's performances at the opening rounds.
Newey admitted the team's rush to get the car ready ahead of this season's regulation change had also led to shortcomings with the car's chassis and aerodynamics.
"On the chassis side, we're quite a long way overweight," he said. "Some of that comes from integrating the power unit and dealing with vibration issues we've had to work through with Honda, but we also didn't do as good a job as we should have on our side at saving weight.
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"When you design in a rush, weight is the first thing that suffers because you don't have the time to thoroughly optimise everything.
"Aerodynamically, we also took a bold direction -- which was largely pushed by me -- without the luxury of exploring multiple concepts in depth because time was against us. I wouldn't say the direction we've taken is fundamentally wrong, but it has thrown up challenges we didn't anticipate."
Aston Martin has opted against bringing regular upgrades to its car this year and is instead working towards a significant update -- largely targeted at weight reduction -- at the Hungarian Grand Prix.
"The main structural elements remain the same -- the chassis and gearbox architecture don't fundamentally change -- but we've taken weight out of both, which required re-homologating and crash testing the forward chassis," Newey said of the upgrade.
"The front suspension is unchanged. The rear suspension is slightly revised. We've developed a new nose and substantially revised aerodynamic surfaces. So, while the core structure is similar, it's a big aerodynamic package coupled with significant weight reduction. The target is to get very close to the weight limit."