I heard someone say that human body doesn't require sleep time of 8-10 hours which usually people take.
Human body doesn't demand of sleep it just demands for rest which is maintenance time for body to rejuvenate itself and sleeping is just one form of rest.
If you can rest in a sitting position or even standing position you don't need to sleep but for that you need to have a stable mind.
earlier, i rarely used to sleep, like at 4 am and wake up 4 hours later
first few days, it was okay, but then i caught the habit
even if i tried sleeping earlier, i couldn't and my sleep cycle was de_stroyed