F1 cooling vests: What are the new FIA measures causing drivers trouble in 2025?

The FIA's all new F1 cooling vests have been introduced for the 2025 season, in a bid to help drivers keep cool during the hotter races on the calendar.

In response to the 2023 Qatar Grand Prix - where Logan Sargeant withdrew from the race because of heatstroke, Esteban Ocon threw up in his helmet and Lance Stroll briefly passed out - the FIA introduced the cooling vests to help drivers regulate their body temperature during extreme conditions.

The wearable-tech shirts were made available for this season but remain optional, with several drivers confirming the design was not quite right at the 2025 Bahrain Grand Prix.

However, with the cooling vests set to become mandatory for the hottest races in 2026, what exactly are they and how do they work?

What are F1's cooling vests and how do they work?

F1's new cooling vests combine a shirt with nearly 50 metres of tubes that pump cooled fluid around a driver's torso, with the water stored in a dedicated box in the car that houses a micro-processor and the technology to keep the temperatures down.

Teams can currently only fit it to their cars when temperatures reach a certain threshold, which has been set at 31 degrees Celsius and is based off FIA sensors around a circuit rather than the heat in the cockpit.

Drivers have been given the option of using it in 2025, as this year will also be used to test the new device to inform further tweaks for 2026.

Oscar Piastri expressed his concern with the weight of the cooling system in Bahrain, and claimed that if it was used 'it would come with a weight penalty', which would give a driver a natural disadvantage in the car - rather than an actual sporting penalty.

According to the FIA, if a driver chooses not to wear a cooling vest in 2025 they still have to carry an extra 500g in ballast within their cockpits, so they do not gain a competitive advantage for not using the cooling system.

When the regulations and cars change in 2026, the cooling systems will be powered by the electrical systems of the new car designs and will therefore be carried at all times.

However, Esteban Ocon has been critical of the current design, which he described as 'unusable' to the media at the Bahrain Grand Prix.

"The product itself, which is standard, is not usable. It's too big. You know how tight the seat is in Formula 1 everywhere. Where all the tubes linked up, it's like a knot of tubes. And that's why it's too big," he said.

Ocon continued that the cockpit seats could not be modified to accommodate the cooling system, and added: "Well, if you want a seat with a massive hole in it, no. A seat is very difficult to get right. If you do a cut-out like that, you will lose in flexibility massively."

"So the only way I see it improving is if we manage to have less of that knot, or if we come up with a solution where in some road cars, for example, there is air conditioning through the seat, which we do not have to have on the way."

The Frenchman was one of a few drivers who questioned whether the system was necessary in the first place, with Lewis Hamilton also concurring that drivers had coped without it in hot conditions before and stated that 'racing needs to be tough.'

Only time will tell if F1's new cooling vests will help or hinder performance in 2026, but if the drivers are to be believed more work needs to be done to the system before they become mandatory.

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