Because of the speed of the cars, you not only need fast reflexes but also a strong body because you can reach multiple Gs. Racing in those conditions is very tiring.

Moreover, you should go look at the wheels for F1 cars. There are way too many buttons to count because nearly nothing is automatic in F1 cars. Pilots have to be able to understand situations and think fast about what they will do. Adding to this is general strategy during the race.