Yes I agree that 7 to 8 hours of sleep is necessary for a busy man, but that sleep should be very healthy sleep, if we can get 4 hours of Healthy sleep, then we do not need to sleep 8 hours. Thomas Alva Edison : Edison was known to sleep very little. He worked tirelessly for days, only to crash afterward and sleep for long stretches, sometimes longer than a day. 2. Nikola Tesla He slept for less then 2 hours a day. And many more Great people's are there who slept for less then 4 hours. Come Back to me: When i go to bed for sleep i fall in sleep with in 2 minute and full of dreaming when I wake up I just realize that I sleep more hours but actually sleep for 4 hours. And feel like fresh. Research says when you are dreaming that the best sleep you taken. And when i sleep for 3 hours in night or 20 minutes nap in day dreams are there. I know my English is sh*t . sorry Bit this is my real life experience. I,m doing this for last 3 months i guess. So if u wa...