You are sleeping 6 hours every day and it is enough to you?
If I do not sleep at least 8 hours then I cannot be productive to my work as I am feeling too much tired and I cannot endure the day.
The amount of sleep varies to age.
A working person can get enough sleep with the minimum of at least 4 hours. I have read something like that with an article and that's why I have understood before why I'm getting not that much sleep.
But it's advisable every day at any age to get at least 8 hours of sleep.