Autosport has reported:

Formula 1 drivers remain split over cooling vests as the championship prepares for its fourth heat hazard race of 2026 in Singapore. Some say the equipment helps them cope with high temperatures, while others question its comfort, reliability or place in the sport. The debate intensified after Mercedes driver George Russell urged the governing body to improve the rules around the system.

The discussion follows concerns about driver comfort in hot conditions that arose after the 2023 Qatar Grand Prix, where several drivers showed symptoms of heat exhaustion. The FIA and all F1 teams then commissioned extensive research, which led to a standard vest that circulates water through a network of tubes.

The FIA declares a heat hazard when temperatures are expected to exceed 31C. Under that designation, drivers must either wear the cooling vest or have 0.5kg of corresponding ballast added to their car. The original design has been unpopular with some drivers because its cooling effect can last only a handful of laps and the equipment can be uncomfortable in the cockpit.

To support improvements, the FIA offered teams a cost cap exemption of 50,000 USD for developing a cooling system proven to work for an entire race. Teams were also offered a 75,000 USD allowance to improve the vest’s comfort and effectiveness. Mercedes chose not to pursue a bespoke system, saying the allowance was insufficient and that it preferred to direct engineering resources toward making its car faster.

Russell made the case for greater regulatory action in an interview with The Times. He said resources put into vests used only occasionally would otherwise go toward improving the performance of his W17. Mercedes is trying to stay ahead of McLaren, Red Bull and Ferrari as those teams make progress, and the current debate is centred on comfort rather than an immediate safety concern.

Several drivers have rejected the vest outright. Red Bull’s Max Verstappen and Isack Hadjar are among those who say it should not be part of the sport. Speaking in Singapore, Hadjar said: “I think it should be banned, because it's supposed to be tough.”

Verstappen objected to both the equipment’s usefulness and the cables inside the car. “For me it's not needed. Yes it's hot, but it's not a sauna, and with this cooling vest you have these stupid cables in your car, so it's just limiting your movement as well. Even if it would work for one and a half hours, like cool cool, I don't need it. But it doesn't work anyway for one and a half hours.”

Alpine driver Franco Colapinto also described the heat as a longstanding feature of the sport and said the vest was not comfortable for him. “Yes, I think it's hot, but it's been hot for the history of the sport. It's good to have it as an option. Personally, I don't like it. I don't feel it's comfortable.”

Russell’s Mercedes teammate Kimi Antonelli said he stopped using the standard system after two difficult experiences during his debut campaign last year. In one instance, it failed to work for as long as expected; in another, the pump malfunctioned and circulated water at 50 degrees throughout the session. Antonelli said he suffered heat stroke after that session.

“When I wore it last year, I had two very bad experiences,” Antonelli said. “The first time it didn't work as long as we hoped for. The second time, the pump system failed and I did the whole session with the system pumping the water at 50 degrees. I suffered a heat stroke after the session, so it wasn't very pleasant.”

He said the incidents led him to focus on heat acclimatisation through training, while leaving open the possibility of using a more dependable system in future. “Ever since, I was like: 'You know what, I'm going to train hard so I don't have to use it for the weekends. If we get to a point where it's developed and we have the confidence that it's going to work every time and for the time that we need to, I think it's very nice because it definitely keeps you cool. But now there's so much uncertainty.”

Ferrari’s Charles Leclerc said he would prefer a vest that works for part of a race to having no cooling equipment at all. He estimated that the system can help for 15 or 20 laps before the driver becomes warm again. “Ideally, if I can have an even better cooling vest, I will always take it,” he said. “Let’s say that for 15, 20 laps it works pretty well. Then after, for the rest of the race you are quite warm, just like you are with other cooling vests. At least I’m getting 15, 20 laps, and I’m already grateful for that.”

Leclerc acknowledged that drivers differ in their preferences. “Some drivers don't even want to hear about the cooling vest, but that's the preference of each single driver.”

Williams driver Carlos Sainz is among the system’s strongest supporters. He said Williams had prioritised vest development and that the equipment had made a positive difference for him and teammate Alex Albon. “If there's one thing as a team we've done well on development this year, it's the cooling vest, which has definitely given Alex and me a good time inside the car. We're very happy to have it. I see Mercedes' point. At the same time, we've prioritised it more than Mercedes, and that's why we have it going and working better.”

Haas driver Esteban Ocon also said the system had improved his physical performance, although its cooling effect did not last through a full race. Since its introduction, he said, it had run for about 40 minutes before circulating hot fluid in the heat inside the car. “I think it's been a massive performance gain for the physical aspect of things,” the Frenchman said. “Of course, it hasn't worked the whole race since we introduced the system. It lasts for like 40 minutes, and then it's just hot fluid that keeps going on because it's so hot in the car. But it's already good that we have something, because I've raced my whole career before that without.”

Ocon said athletes perform better when their body temperature is managed. “I don't think everybody realises how much better it is for an athlete to be at the right temperature to perform.”