F1 drivers typically lose 2–3 kg (4–7 lb) of body weight during a race, and in the hottest, most humid events it can climb to 4–4.5 kg (9–10 lb) , almost all of it sweat and fluid loss.

How much weight do F1 drivers lose?

  • Usual range: around 2–3 kg per race in normal hot conditions.
  • Extreme races (Singapore, Malaysia, Qatar‑style heat): up to 4 kg or more reported, especially for taller drivers.
  • Individual quotes: Lewis Hamilton has said he can lose about 10 lb (≈4.5 kg) in particularly tough races.

So a good rule of thumb: several kilos every race, and up to ~4–4.5 kg on brutal hot tracks.

Why do they lose so much?

  • Intense heat in the cockpit : Temperatures can approach 50°C inside the car, especially at night races in humid climates like Singapore.
  • Heavy sweating in race suits : Fireproof overalls, gloves, balaclava and helmet trap heat; drivers can lose multiple kilos of fluid through sweat alone.
  • High G‑forces : Cornering and braking can put up to 5–6 g on the body, so muscles are working constantly just to hold posture and keep control.
  • Limited drinking : They have a drinks bottle, but they still finish the race in a dehydrated state, which shows up as rapid weight loss when they’re weighed afterward.

An easy way to picture it: it’s like doing a high‑intensity workout in a sauna, strapped into a 300 km/h machine, for up to two hours straight.

Why are drivers weighed after the race?

  • To check health and dehydration after that fluid loss.
  • To monitor how much weight they lost and adjust hydration and training plans.
  • Because total weight matters for performance : even 1 kg can cost noticeable lap time, so teams track driver weight very closely.

Mini “forum style” take

“Think of it as a 90–120 minute HIIT session in 50°C wearing a winter coat.
End result: you step off the car 2–4 kg lighter, and most of that is sweat.”

TL;DR

F1 drivers usually lose 2–3 kg in a race and can hit 4–4.5 kg in extreme heat, almost entirely from sweating in a super‑hot cockpit under massive physical strain.

Information gathered from public forums or data available on the internet and portrayed here.