does 4 hours sleep a day can keeps your mind active?

[KosMas]

I think it is not true that some people can be very effective with 4 hours of sleep, I have to sleep at least 7 hours be productive.

[Squishy01]

I've been sleeping for around 4 hours or less than every day for around 1 year now. I don't really know if it affects my mind as I seem to be doing well, but what it does affect is my body. I have gained a lot of weight and I believe it is because of my constant lack of sleep. Experts attribute weight gain to lack of sleep so if you don't want to get fat, sleep right! 

[VilliGano]

Nikola Tesla slept and less