The idea of a driver-cooling system was intimated after the 2023 Qatar Grand Prix, when heat and humidity left several drivers on the brink of collapse.
A number of drivers needed medical attention after the race, Frenchman Esteban Ocon vomited in his helmet, and Williams driver Logan Sargeant retired because he could not cope with the conditions any longer.
The drivers have had a mixed response to the vests, with some feeling they are uncomfortable and not especially effective.
Sainz said: “Teams are managing to make it work better and better every time we run it. At the beginning, we had it to work more or less for half an hour. Hopefully now the whole system can work at least for an hour.
“It’s a two-hour race. I’ve done it 10 times in Singapore. If it breaks or it doesn’t work, I’m not worried. I’ll do the race and jump out fresh like I always do. But if it works, it’s better, because then you suffer a bit less.”
Sainz said he had used the system in the Saudi Arabian Grand Prix earlier this year, and it lasted about 15-20 minutes.
Mercedes’ George Russell tried it out in Bahrain, and said that it was “definitely very noticeable”.
Russell added at the time: “At the start of the race, it was about 16°C pumping around my body, which feels quite nice when you’re in a cockpit that’s 50°C-plus.”