How much weight do F1 drivers lose in a race?
In the hottest races as much as 3 to 4 kg, by Formula 1's own figures for Singapore. Almost all of it is water lost as sweat, and it goes back on with the drinks after the race.
The numbers from the paddock
Formula 1's race programme for Singapore says drivers can lose as much as 3 to 4 kg over a race there. ESPN puts it at as much as three kilos, about three litres of sweat, or 4 to 5 percent of a driver's body weight. After the 2024 race Nico Hulkenberg said he had lost 3 kg in sweat, and Charles Leclerc's trainer Andrea Ferrari has said drivers can lose up to 3 kg in Singapore.
And the 5 kg you hear about?
You will see five kilos quoted online. We could not find it in a source we trust: the figures from Formula 1, the teams and the reporters in the paddock stop at 3 to 4 kg, and those are for the hottest races of the year. On a cool day in Europe the loss is much smaller, and none of the sources here puts a number on it.
Why sitting in a car makes you sweat that much
The driver wears a fireproof suit, gloves and a helmet in a cockpit that Formula 1 says can go above 60 °C. The heart runs at around 150 to 170 beats a minute for the whole race, and the neck and core hold out against the G forces in every corner. In Singapore the race takes close to two hours in humidity above 75 percent, so sweat barely dries and the body keeps making more of it.
It is water, not fat
A 90 minute race burns about 935 kcal by the Compendium of Physical Activities, the table researchers use for this. A kilo of body fat holds far more energy than that, so almost all of the 3 kilos is water and salt leaving through the skin. Leclerc's trainer says the sweat also takes calcium and minerals that the muscles need to work.
How they get it back
Lando Norris said after the scorching 2023 Qatar race that it was probably the first time he had ever drunk from his bottle during a race. After every race the drivers are weighed, because since 2019 the driver counts for at least 80 kg in race kit and a lighter one carries ballast. Then comes the slow part: Alex Albon said that after Qatar he ate a lot, almost over ate, just to get some calories back.